b737 ng gen fam

SECTION TITLE

1 Introduction

2 Structures

3 Equipment Centers

4 Flight Compartment

5 Common Display System

6 Communication and Recording

7 Navigation

8 Autoflight

9 Electrical Power

10 Fuel

11 Auxiliary Power Unit

12 Power Plant

13 Hydraulics

14 Landing Gear

15 Flight Controls

16 Environmental Systems

17 Fire Protection

18 Ice and Rain

19 Cabin Systems

20 Lights

21 Airplane Access

Abbreviations and Acronyms

Table of Contents

Introduction

November 2000 1-1

• Operating Experience

• Self-Sufficiency

• Eye-Level Maintenance

About This Book

This document presents a generaltechnical description of the Boeing737. It is based on the standardairplane, but also includes details ofsome of the most popular options.

For detailed information, orinformation on a specific customerairplane, refer to these publications:

• Airplane Flight Manual• Operations Manual• Airplane Maintenance Manual• Configuration Specification

Document• Configuration Control Document.

If the information in this book doesnot agree with the information in anyof these publications, thepublications should be used.

OVERVIEW

To understand the airplane, it isnecessary to understand the airplanesystems. This document gives anintroduction to the systems in the737.

Each system is shown from acomponent, installation, andoperational view. Flight compartmentinstruments and panel data helpshow system operation.

Principal Characteristics

The main characteristics and majorstructural differences of the 737-600,-700, -800, and -900 are shown onthe subsequent pages. Each airlineselects different options. All optionsare not shown in this manual. Most ofthe systems are similar betweenmodels; only the major differencesare covered.

1-2 November 2000

Airplane Dimensions

The wing span and horizontal tailspan is the same for all models in thenext generation family. Thedimensions are shown above.

Airplane Dimensions

112 ft 7 in

47 ft 1 in(34.4m)

(Ref)(14.3m)

117 ft 2 in(35.7m)

(With Winglets)(Unloaded)

117 ft 7 in(35.8m)

(With Winglets)(Loaded)

18 ft 9 in(5.7m)

12ft 4 in(3.8m)

Introduction

November 2000 1-3

41 ft 3 in110 ft 4 in(12.6m)(33.6m)

737-700

41 ft 2 in(12.5m)

13 ft 5 in 36 ft 10 in102 ft 6 in

41 ft 3 in

737-600

(12.5m)

(11.2m)(31.2m)

(4.0m)(Typ)

Airplane Dimensions

51 ft 2 in129 ft 6 in

737-800

(15.6m)(39.5m)

41 ft 2 in(12.5m)

737-900

56 ft 4 in(17.17m)

41 ft 2 in(12.5m)

138 ft 2 in(42.11m)

21 ft 1 in(6.4m)

(With Winglets)

21 ft 1 in(6.4m)

(With Winglets)

1-4 November 2000

Operating Experience

The 737 models now in service havea high dispatch reliability. The 737flies a large number of short lengthflights. It can also fly longer rangeflights. The airplane use rate is veryhigh. The use rates are shown thisway:

• Average daily utilization 7.6 hr• Average flight length 1.4 hr• Schedule reliability 99.3%.

The 737-600/700/800/900 designimproves on the 737/300/400/500model design. These are theimprovements:

• Larger payload• Higher service ceiling• More range• Improved fault isolation• Improved systems design• Flight compartment common

display system.

The range map above shows thelonger range of the 737-600/700/800/900 over the 737-300/400/500aircraft. The ranges are for aircraft inthese conditions:

• Normal flights• Full passenger payload• 85% annual winds.

Airplane Ranges

Seattle

San FranciscoDenver

Mexico CityMiami

Madrid

Paris

London

Oslo

Bogota

Reykjavik

New York

737-600/700

Los Angeles

737-800/900

737-300

737-400

737-500

Introduction

November 2000 1-5

12 ft 4in(3.76m)

(typ)

Principal Characteristics

667(18.9)

Fwd

737-600 737-700 737-800

Maximum Gross Weight, Pounds (Kilograms)

Taxi

Brake Release

Landing

Zero Fuel

Engine Thrust, lb

BasicOption

Fuel capacity, U.S. Gallons (liters)

PassengersMixed ClassAll Tourist, 32-in PitchAll Tourist, 30-in Pitch

Lower Hold Volume,

Speed CapacityMaximum Operating Airspeed, Knots (KCAS)Maximum Operating Mach Number

124 500(56 473)

124 000(56 246)

120 500(54 659)

113 500(51 484)

CFM56-7B18CFM56-7B20

108123130

257(7.3)

3400.82

to 144 000(65 318)

143 500(65 092)

19 50020 600

6878(26033)

745(21.1)

488(13.8)

133 500(60 555)

133 000(60 328)

128 000(58 060)

120 500(54 658)


128140148

386(10.9)

to 153 500(69 626)

153 000(69 400)

128 000(58 060)

120 500(54 658)

20 60022 700

6878(26033)

982(27.8)

596(16.9)

156 000(70 762)

155 500(70 535)

144 000(65 318)

136 000(61 690)


160175189

to 173 000(60 780)

172 500(60 550)

24 20026 300

6878(26033)

1566(44.3)

899(25.5)

144 000(65 318)

136 000(61 690)

Service Ceiling 41 000 feet12 497 meters

Option CFM56-7B22 CFM56-7B2422 700 24 200

Fwd Aft Total Fwd Aft AftTotal Total

113 500(51 484)

120 500(54 659)

CFM56-7B27

737-900

164 500(74 615)

164 000(74 380)

146 300(66 360)

138 300(62 732)

to 174 700(79 243)

174 200(78 240)

146 300(66 360)

138 300(62 732)

27 300

CFM56-7B24 24 200CFM56-7B26 26 300CFM56-7B27 27 300

6878(26033)

177189189

840

Fwd

18521012

Aft Total

(23.8) (28.7) (52.4)

ft3 (m3)

171 500(77 791)

171 000(77 564)

134 000(60 781)

126 000(57 153)

737-700C

1-6 November 2000

Dorsal

Redesigned Airfoil and

Redesigned NoseRedesigned

Tip Extension

Additional Flight Spoiler

Flap Track Fairings

Landing GearMain Landing Gear

RedesignedKrueger Flaps

Additional Slat

Increased Wing Span

Fin

Lengthened VerticalStabilizer

Increased HorizontalStabilizer Span

CFM56-7 Engine

Revised Aft

Fairing ShapeWing-Body

New APUand Firewall

Redesigned EECompartment

StrengthenedStabilizer andCenter Section

Major 737 Changes

Winglet Option

(Typical)

737 Changes

From 737-500 t0 737-600(No Difference in Fuselage Dimensions)

Introduction

November 2000 1-7

From 737-300 to 737-700(No Difference in Fuselage Dimensions)

46-inch (117-cm)

Expanded Environmental

Body Extension

Control System (ECS)

64-inch (163-cm)Body Extension

Tail Skid

From 737-400 to 737-800(Additional Changes)

737 Changes

From 737-800 to 737-900(Additional Changes)



1-8 November 2000

Self-Sufficiency

The airplane can operate atimproved and unimproved airports.These are the systems that make theairplane self sufficient:

• The APU supplies on-ground orin-flight electrical power

• The APU supplies air for enginestarting

• The APU maintains an air-conditioned cabin during groundoperations

• The APU is started from theairplane battery

• The airplane has large fuel andwater capacity

• Alternative systems allowdispatch with inoperativesystems

• Two or more systems which haveequal function but one systemoperates at a time which allowsmore rapid fault dispatching

• Self-contained airstair (option).

Eye-Level Maintenance

This design permits eye-levelmaintenance access at ground level.This permits easy access to systemsand unit modules. Many majorsystems are grouped together.

The operator benefits from minimummaintenance cost and low rampturnaround times. Less money isspent to purchase maintenanceequipment.

Engines are changed at groundlevel. Hand operated hoists attach tothe airplane engine struts to removeand install engines.

Component and System Access

The major hydraulic components,are in the main landing gearwheelwell and can be maintained atground level.

The air-conditioning units are easy toreach. They are behind two doorsunder the wing center section.

Access doors, forward and aft of thenose wheelwell, give access toelectronic equipment compartments.

Extension of forward and aft winghigh lift devices permit access toother system components.

Potable water and lavatory systemsare easy to maintain because ofground access to their servicepanels.

Built-in-Test

Built-in test (BITE) and checkoutfunction for systems simplify faultisolation. Many airframe/enginemodules and most avionics modulesinclude BITE. BITE access is at theface of the module or through theflight compartment control displayunits (CDU).

Airplane Servicing

Hydraulic ServiceBrake and

ServicePotable Water

HandlingBaggage

Fueling

Baggage Handling

Galley Service

Galley Service

Optional Airstair

Air Conditioning

Ground Air

Lavatory Service

Structures

November 2000 2-1

• Fuselage

• Wing

• Stabilizers

• Composites

Features

BASIC STRUCTURALDESCRIPTION

The airplane is a low wing twinengine design. The engines arebelow the wings on struts. It has fullcantilever wings and tail surfaces.The fuselage is a semi-monocoquedesign.

HIGH-FATIGUE DESIGN LIFE

The design service objective is75,000 flight cycles. For typicalairline operations, the aircraftreaches this objective after 25 yearsof service.

CORROSION PREVENTION

Years of extensive in-serviceexperience lead to an optimumairframe design. This knowledgealong with new material technologygives the operator an airframe thatresults in:

• Minimal corrosion• Longer in service periods• Less maintenance costs.

2-2 November 2000

Fuselage

The fuselage is a pressurized semi-monocoque structure. The primarymaterials for the fuselage arealuminum alloys.

Pressure bulkheads at the forwardand aft ends of the fuselage form apressure vessel.

These auxiliary structures attach tofuselage:

• Nose radome• Wing-to-body fairing• Tail cone.

Fuselage

Forward Pressure

Aft PressureBulkhead

Wing-To-Body Fairing

Tail Cone

NoseRadome

Floor Beams

Frames

Stringers

Bulkhead

Structures

November 2000 2-3

Wing

The wing is a cantilever structure.The basic wing structure isaluminum. The wing has thesefeatures:

• Stores fuel• Contains fuel system

components• Attach points for the engine strut,

landing gear, and flight controlsurfaces.

Fuel tank access panels on thebottom wing skin permit access tothe fuel tanks.

Wing

Slat

Flaps

Ground Spoiler

Flight Spoiler

Aileron BalanceTab

Aileron

Wing Tip

Leading Edge Flap

Engine Nacelle/Pylon

Rib

Fuel TankAccess Panel(Typical)

AccessCutout

2-4 November 2000

Stabilizers

The horizontal and vertical stabilizersare made of aluminum alloys. Theelevator and rudder are made ofgraphite.

Horizontal/Vertical Stabilizer

Vertical Stabilizer

Horizontal Stabilizer

Removable

Front SparRudder

Rear Spar

Dorsal Fin

Front Spar

Rear Spar

Center SectionTruss Structure

Elevator

Leading Edge

Structures

November 2000 2-5

Composites

Some airplane structure and partsare made from composite materials.These are some advantages ofcomposite materials:

• High strength• Corrosion resistant• Increased fatigue life• Light weight.

Composites

Aileron

Aileron Tab

Trailing Edge Panels

Dorsal Fin

Flap Track

Inboard and OutboardFixed Trailing Edge

Fairings

Rudder

Tail Cone

Elevator

Wing-To-BodyFairing

Radome

Thrust Reverser

GRAPHITE

FIBERGLASS

FIBERGLASS/GRAPHITE

Outboard FixedLeading Edge(Fiberglass)Nose

Landing Gear Door(Graphite)

Inboard Fixed Leading EdgeLower Skin Panel(Fiberglass)

Equipment Centers

November 2000 3-1

• Electronic EquipmentCompartment

Features

ACCESSIBLE LOCATION

Most electronic equipment is in acompartment below the cabin flooraft of the nose wheel well. Thiscompartment is easily accessiblefrom ground level.

TRANSVERSE RACK

The electronic equipmentcompartment includes 3 equipmentracks. The main equipment rack is atransverse rack across the aft end ofthe compartment. Equipmentremoval and installation is easy dueto the rack design. Interconnectingwiring, mounts, and accessory boxesare accessed through panels in theforward cargo compartment.

3-2 November 2000

Optional E6 Rack(Aft Cargo Compartment)

Electronic EquipmentCompartment

Electronic Equipment

E3

E2

E1

E4

E5

Optional E8-1 Shelf(Not Shown)

Equipment Centers

November 2000 3-3

Electronic EquipmentCompartment

Electronic equipment is in acompartment below the main cabinfloor aft of the nose wheel well. Onthe ground, you enter this electronicequipment (EE) compartmentthrough a door in the bottom of thefuselage.

There are five standard equipmentracks. These are the E1, E2, E3, E4,and E5 racks. More equipment racksmay be needed on airplanes withoptional systems.

Shelf assemblies have equipmentmounts, interconnected wiring, andaccessory boxes. They are easy toremove. This makes troubleshootingand modification easier. Equipmentthat installs boxes on shelves isadjustable. Access to the mostfrequently used boxes is improved.

Most equipment rack shelves arecooled with air. Air is blown throughor drawn through the equipmentracks.

There is a drip shield over the racksto protect the equipment frommoisture condensation.

Electronic Equipment Compartment

E1-1 Shelf(Blow ThroughCooling)


E1-5 Shelf(Draw ThroughCooling)


E1-4 Shelf(Draw ThroughCooling)

Flight ControlComputerChannel A

TCASComputer

AutoThrottleComp

IFSAU Flap/SlatElexMod

GndProx

Anti-SkidAutoBrakeControl

VHF

1

DME1

ATC1

VOR/MB1

MMR1

VHFComm

2

ATC2

DME2

VOR2

MMR2

Flight ControlComputerChannel B

OverheatContMod

ComPAAmp

Electronic Equipment Rack E1 (Typical Arrangement)

3-4 November 2000

E2 RackE3 RackE4 Rack

ENG

MUXAUDIO

SATCOMSATCOM

2 1

POWERDISTRIBUTION

PANEL 2

BUSPWRCONTUNIT

AUTOSPEEDBRAKE

ACCESSMOD

WINDOWCONT

T/R3

GCU2

T/R2

SEL-CAL

CDS DEU2

CDS DEU1

RADALT

1

ENGVIBSIG

COND

SYMD2

SYMD1

STATICINVERTER

APU STARTCONVERTER

APU STARTPOWER

UNIT

WINDOWCONTROL

GCU1

T/R1

BATTERY

VHF3

ACARSMU

POWERDISTRIBUTION

PANEL 1

APUGCU

BATTERYCHARGER

PRIMARYBATTERYCHARGER

CABPRESSCONT

1

FIRE&

APUDET

CONTMOD

UNIT

ADF12

ADF

RADALT2

DFDAU ACC

ENTPLAYER

AUX BATTERYCHARGER

CABPRS

CONT2

REUCAB

TEMPCONT

AIRCONRLY

4

WINDOWCONT

3

Electronic Equipment Racks E2, E3, and E4 (Typical Arrangement)GCU

J9 PANEL

Electronic Equipment Compartment

ADIRUL FMC

2 ADIRURFMC

1

Electronic Equipment Rack E5 (Typical Arrangement)

Equipment Centers

November 2000 3-5

Optional Electronic EquipmentRacks

Two optional equipment racks areavailable when more space isnecessary.

The E8-1 shelf is above the E1 rackin the EE compartment. The E8-1shelf has blow-through cooling. TheE8-1 shelf option is available whenairstairs are not installed.

The E6 rack is in the aft cargocompartment. The E6 rack is notcooled.

Airplanes that do not have theoptional E6 rack have a mount in theaft cargo compartment for the voicerecorder and the APU electroniccontrol unit (ECU). This mountlocation is the same as the E6location.

Optional Electronic Equipment Racks (Typical Arrangement)

E6 Rack(No Cooling)

(Aft Cargo Compartment)

SATCOMVoice Recorder

E8-1(Blow Through Cooling)

(EE Compartment)

HF-1 HF-2WeatherRadarTransceiver

HF 2

APUECU

HF 1

E6 Rack(No Cooling)

(Aft Cargo Compartment)

FWD

Flight Compartment

November 2000 4-1

• Flight Compartment Panels

• Glareshield Panel

• Instrument Panels

• Center Forward Panels

• Control Stand

• Aft Aisle Stand Panels

• Overhead Panels

• Other Flight CompartmentComponents

Features

DESIGN PHILOSOPHY

The flight deck maintains the sametype-rating as all previous 737s,while integrating refinements provenon the 737 with innovative 777technologies.

FLAT PANEL LIQUID CRYSTALDISPLAY UNITS

The flat panel liquid crystal displayunits need less power and have alarger display area than conventionalCRT display units.

MODE CONTROL PANEL

The mode control panel usesintegrated LED light switchassemblies to increase reliability.

4-2 November 2000

Flight Compartment Panels

The main instrument panel has threepanels. These are the panels:

• P1• P2• P3.

The P7 glareshield panel is abovethe main instrument panels.

These are the aisle stand panels:

• P8 aft electronic panel• P9 forward electronic panel• Control stand.

These are the two overhead panels:

• P5 forward overhead panel• P5 aft overhead panel.

Flight Compartment Panels

P1 Captain

P3 First Officer

P5 Forward

P5 Aft

P7 Glareshield Panel

P8 Aft Electronic

P9 ForwardElectronic Panel

P2 Center

Instrument Panel

Panel

Instrument Panel

Instrument Panel

Overhead Panel

Overhead Panel

Control Stand

Flight Compartment

November 2000 4-3

Glareshield Panel

The glareshield panel is the P7panel. The P7 panel contains thesepanels:

• Mode control panel (MCP)• EFIS control panels• Master caution annunciations• Fire warning light.

The MCP uses integrated LED lightswitch assemblies. This designimproves the reliability andmaintainability of the mode controlpanel.

The EFIS control panels are on theglareshield panel for easier accessby the pilots. These control panelsare similar to the Boeing 747-400and 777 EFIS control panels.

Glareshield Panel

P7 Glareshield Panel

COURSE

4-4 November 2000

Captain Instrument Panel

The captain instrument panel is theP1 panel. The P1 panel has thesefeatures:

• Left outboard display unit• Left inboard display unit• Display switching module• Clock• Autoflight status annunciator• Conditioned air outlet controls• Lighting controls for the captain• Master dim and test switch• Yaw damper indicator.

The display switching modules letthe pilots show different displayformats on the inboard and lowerdisplay units.

Main Instrument Panels

P1 Captain Instrument Panel

Flight Compartment

November 2000 4-5

First Officer Instrument Panel

The first officer instrument panel isthe P3 panel. The P3 panel is almostthe same as the P1. The P3 panelalso has these features:

• Ground proximity module• Brake pressure indicator.

P3 First Officer Instrument Panel

Main Instrument Panels

4-6 November 2000

Center Instrument Panel

The center instrument panel is theP2 panel. The P2 panel has theseitems:

• Engine control module• Antiskid and autobrake switches

and lights• Landing gear lever and position

indicators• Upper center display unit• Standby instruments.

Center Instrument Panel

P2 Center Instrument Panel

Flight Compartment

November 2000 4-7

Forward Electronic Panel

The forward electronic panel is theP9 panel. The P9 panel containsthese displays:

• Lower center display unit• Control display units.

Forward Electronic Panel

P9 Forward Electronic Panel

4-8 November 2000

Control Stand

The control stand has controls thatare easy to reach by either pilot.

The control stand has these controls:

• Forward thrust levers• Reverse thrust levers• Takeoff/go-around switches• Speed brake handle• Horizontal stabilizer manual trim

wheels• Parking brake lever and

indication light• Flap lever• Stabilizer trim cutout switches• Horn cutout• Engine start levers.

Control Stand

P9 ForwardElectronicPanel

ReverseThrust Levers

ForwardThrust Levers

Takeoff/Go-AroundSwitches

Flap Lever

Horn Cutout

Start Levers

P8 AftElectronic

HorizontalStabilizerManual TrimWheels

1 2

25

15

10

30

40

5

2STABTRIM

UP

21

StabilizerTrimIndicator

ParkingBrake Lever

StabilizerTrim CutoutSwitches

Panel

STABTRIM

Speed BrakeLever

Flight Compartment

November 2000 4-9

Aft Electronic Panel

The aft electronic panel is the P8panel. The P8 panel has thesefeatures:

• VHF and HF radio control panels• Nav control panels• Audio control panels• ADF control panel• ATC control panel• Cargo fire panel• ACARS interactive display unit• Aileron and rudder control• Lighting controls• Weather radar control panel.

Radio tuning panels can replaceindividual radio control panels. Theradio tuning panels tune the VHF andHF radios from one control panel.

Aft Electronic Panel

P8 Aft Electronic Panel

4-10 November 2000

Aft Overhead Panel

The P5 aft overhead panel hascontrols that are seldom used inflight.

The P5 aft overhead panel has thesecontrols and Indications:

• Leading edge devicesannunciator panel

• Inertial system display unit• IRS mode selector unit• Service interphone switch• Dome light switch• Observer’s audio control panel• Reverser fault lights• Engine control lights• Electronic engine control (EEC)

alternate mode light/switches• Passenger and crew oxygen

system• Flight recorder test panel• Mach/airspeed warning panel• Stall warning test panel• Landing gear down & locked

indicator lights.

Forward Overhead Panel

Because of its central location, eitherpilot can reach any of the systemscontrols. The panel has controls forthese systems:

• Flight controls• Instrument switching• Fuel• Electrical• Window and air data probe heat• Engine and wing anti-ice• Hydraulics• Door warning• Voice recorder• Air-conditioning• Pressurization.

The forward overhead panel hasswitches for these functions:

• Overhead panel lights• Equipment cooling• Emergency exit lights• Passenger signs• Rain removal

• Exterior lights• APU• Engine start.

The primary system control panels,fuel, electrical, hydraulic, and airconditioning, are light grey.

Aft Overhead Panel

P5 Aft Overhead Panel

GPS

Flight Compartment

November 2000 4-11


P5 Forward Overhead Panel

4-12 November 2000

Other Flight CompartmentComponents

The main circuit breaker panels arebehind the first officer and captain.The P6 and P18 have the componentload circuit breakers. Circuitbreakers are organized by airplanesystems.

Emergency equipment is placedwithin easy reach of the crew.Emergency equipment includesthese items:

• A fire extinguisher on the P6panel

• A crash axe on the P18 panel• Escape lanyards above the

sliding windows.

The data loader control panel is onthe P61 panel.

The bulkhead and sidewalls haveprovisions for stowing crew luggage,flight manuals, coats, and hats.

Other Flight Compartment Components

P6 P18

P61

Common Display System

November 2000 5-1

• Common Display System

• EFIS layout

• EFIS

• PFD/ND

• Engine Display

• System Display

• BITE

Features

INTEGRATED FUNCTIONS

The common display system showsflight and engine information to theflight crew. It does the functions ofthe electronic flight instrumentsystem (EFIS), the engineinstrument system (EIS) and most ofthe mechanical primary flightinstruments that are used on the737-300/400/500 models.

RELIABILITY

The system is designed formaximum reliability. The softwaredesign gives a high level of efficiencyand accuracy. The softwarefunctions are separated to increasesafety.

REDUNDANCY

There are two display electronic units(DEUs). Either DEU can drive all sixof the display units.

DISPLAY MANAGEMENT

The display units are inter-changeable. The displaysautomatically switch for any failure toprovide safe displays. Display selectpanels let the flight crew manuallyreconfigure the display system. Theylet the pilots change the type ofinformation that shows on theinboard, outboard and lower centerdisplay units.

BITE

Fault information shows on the flightmanagement computer controldisplay unit (FMC CDU.)

The DEU can store faults in memoryfor sixty-four flight legs.

5-2 November 2000


The common display system (CDS)shows information on six liquidcrystal displays (LCDs). Thesedisplay units (DUs) show primaryflight, navigation, and engineinformation to the flight crew.

The CDS has these components:

• Display electronic units (2)• Coax couplers (4)• Display units (6)• EFIS control panels (2)• Engine display control panel• Display select panels (2)• Display source selectors.

The CDS can show the primary flightand navigation data in two optionalformats. These are the options:

• EFIS• PFD/ND.

The EFIS format shows informationthat looks similar to the 737-300/-400/-500 flight compartment.

The PFD/ND format showsinformation that looks similar to the747 and 777 flight compartmentdisplays.

The CDS can show engineinformation in two optional formats.These are the options:

• Side-by-side display• Over/under display.

You load display electronic unit(DEU) software to change the CDSdisplay formats.

The DEU gets input from the avionicsand airframe systems. It calculatesthe graphics data in the correctdisplay format and sends theinformation to two of the coaxcouplers. Each coupler sendsinformation to all six DUs. This is forredundancy. If one DEU fails, theother can calculate all the necessarygraphics data for all the DUs. If onecoupler fails, a DU can use graphicsdata from any one of its other threeinputs.

The DUs are liquid crystal displayunits. The LCD is a sharper displayover a wide range of lightingconditions than a cathode-ray tubeunit.


DisplayElectronicUnit

DisplayElectronicUnit

CoaxCoupler

CoaxCoupler

CoaxCoupler

CoaxCoupler

ControlPanels

ControlPanels


November 2000 5-3


CONTROL PANELS

The control panels allow the pilots toselect the type of information and thelocation for the displays.

The EFIS control panel controls theprimary flight and navigationinformation. They let the pilotscontrol this information:

• Radio and barometric minimumaltitude

• Barometric reference• Metric altitude display• Weather radar• TCAS traffic display• Navigation display modes• Navigation display information• VOR/ADF display.

The engine display control panelcontrols the engine display and themach air speed indication (MASI) onthe primary EFIS or PFD display. Itlets the pilot select N1 referencebugs, see fuel flow or fuel used data,and select the speed reference bugson the MASI.

The display select panels let thepilots change the information thatshows on a particular display unit toanother display unit. For example,the pilots can select the enginedisplay to show on the lower centerdisplay unit.

The display source selectors let thepilots select the source of data for thedisplays. They can select the sourcefor inertial data and VOR. Theinstrument switching module alsohas a switch to select the DEU tosend information to the display units.An EFIS control panel switch allowsthe pilots to select the EFIS controlpanel to use.


Display Select Panels

ND

MFD

PFD

OUTBDPFD

NORMNORM

INBD

ENGENGPRI

PRI

LOWER DUMAIN PANEL DUs

ON 1

SOURCE CONTROL PANELDISPLAYS

NORMAL

NORMAL

BOTHON 2ALL

AUTO

IRSVHF NAV

NORMAL

NAVIGATION

ON 2ALL

BOTHON 1

BOTHON 1

BOTHON 2

BOTHON R

BOTHON L

Engine Control Module

AUTO AUTOSPD REFN1 SET

EXT gLE FLAPS

a

AUTO BRAKE

DISARMAUTO BRAKE

a

2

31

OFF

RTO

ANTI SKID

MAX

aINOPANTI SKID

V

V

WTV

1

R

REF

MFD

ENG SYS

USED

RATE

FUEL FLOWRESET

2

1 BOTH

L E FLAPSTRANSIT

Display Source Selectors

VOR

TERRPOSDATAARPTWPTSTAWXR

CTR TFC

RST STD

ADF 2

OFF

VOR 2

640

3205

10 1608020 40

BAROHPAIN

MTRS

PLNMAP

APP

ADF 1

OFF

RADIOMINS

BAROFPV

VOR 1

EFIS Control Panels

DEU DEU

5-4 November 2000

EFIS Layout

The outboard display units showvarious displays including attitudeand heading.

The inboard display units also showvarious displays including the NAVdisplay.

The indications on the captain andfirst officer display units are indifferent positions. They are differentto keep this information in the basic-T configuration:

• Airspeed• Altitude• Attitude• Heading.

For example, the mach airspeedindication (MASI) is on the outboarddisplay unit for the captain. TheMASI is on the inboard display unitfor the first officer.

EFIS Display

Capt Primary EFIS F/O Primary EFISF/O Secondary EFISCapt Secondary EFIS


November 2000 5-5

EFIS

The captain outboard EFIS displayhas displays of these functions:

• Mach airspeed indicator• Radio distance magnetic

indicator• Attitude direction indicator• Horizontal situation indicator, 210

degree format.

The inboard EFIS display hasdisplays of these functions:

• Vertical speed indicator• Baro altimeter indicator• Navigation display.

The first officer outboard EFISdisplay has displays of thesefunctions:

• Attitude direction indicator• Horizontal situation indicator, 210

degree format• Vertical speed indicator• Baro altimeter indicator.

The inboard EFIS display hasdisplays of these functions:

• Mach airspeed indicator• Radio distance magnetic

indicator• Navigation display.

The navigation display is one ofseven formats. These are theformats:

• Expanded VOR• Centered VOR• Expanded approach• Centered approach• Expanded map• Centered map• Plan.

EFIS Display

Capt Primary EFIS Capt Secondary EFIS

5-6 November 2000

EFIS

VOR

The VOR mode shows in a centeredor expanded display format.

The centered VOR mode shows 360degrees of the compass rose withthe airplane symbol and the lateraldeviation bar in the center.

The expanded VOR mode shows 60degrees of the compass rose withthe airplane symbol and the lateraldeviation bar at the bottom.

This VOR information shows on thedisplay:

• VOR deviation• TO/FROM annunciation• System source annunciation• Station identification and

frequency• Station bearing• Selected course• DME distance.

This additional information shows:

• Ground speed• True airspeed• Wind speed and direction• Weather radar information• TCAS information.

Centered VORExpanded VOR

VOR Display


November 2000 5-7

EFIS

APPROACH

The approach mode shows in acentered or expanded displayformat.

The centered approach mode shows360 degrees of the compass rosewith the airplane symbol and thelateral deviation bar in the center.Glide slope deviation shows on theside of the display.

The expanded approach modeshows 60 degrees of the compassrose with the airplane symbol and thelateral deviation bar at the bottom.

This ILS information shows on thedisplay:

• Localizer deviation• Glide slope deviation• System source annunciation• Station frequency• Selected runway heading• DME distance.

This additional information alsoshows:


Centered ApproachExpanded Approach

ILS Display

5-8 November 2000

EFIS

MAP

The map mode shows in a centeredor expanded display format.

The centered map mode shows 360degrees of the compass rose withthe airplane symbol in the center.

The expanded map mode shows 60degrees of the compass rose withthe airplane symbol at the bottom.

This map information shows on thedisplay:

• Airplane track and heading• Flight plan waypoints• Flight plan path lines• Active waypoints• Airports• Navigation aids• Distance to go• Estimated time of arrival• Vertical path deviation• Trend vectors• FMC/IRU position difference• FMC source.

This additional information alsoshows:


Map Display

Centered MapExpanded Map


November 2000 5-9

EFIS

PLAN

The plan mode shows in a centeredformat.

The flight crew uses the plan mode tocreate, view or change a flight plan.The display is a north up display. Theairplane symbol shows presentposition and FMC track.

Plan Display

Plan

5-10 November 2000

EFIS

COMPACTED DISPLAY

The compacted display showsautomatically when the inboard orthe outboard display unit fails. Also,you can use the display selectmodule to show the compacteddisplay.

The compacted display has:

• Mach airspeed indicator• Attitude direction indicator• Altimeter indicator• Radio distance magnetic

indicator• Horizontal situation indicator, 360

degree format• Vertical speed indicator.

Compacted Display

Compacted Display


November 2000 5-11

PFD/ND

PRIMARY FLIGHT DISPLAY

The captain and first officer have aprimary flight display (PFD). ThePFD normally shows on the outboarddisplay unit. The PFD can also showon the inboard display unit.

This shows on the PFD:

• Airspeed parameters• Attitude parameters• Barometric altitude parameters• Heading parameters• Vertical speed• Radio altitude parameters• Flight mode annunciations• Landing aids parameters.

NAVIGATION DISPLAY

The captain and the first officer havea navigation display (ND). The NDnormally shows on the inboarddisplay unit.

The ND shows flight and navigationinformation in one of several formats.There are seven formats:

• Expanded VOR• Centered VOR• Expanded APP• Centered APP• Expanded MAP• Centered MAP• Plan.

Primary Flight Display and Navigation Display

PFD ND

5-12 November 2000

PFD/ND

VOR

The VOR mode shows in a centeredor expanded display format.

The centered VOR mode shows 360degrees of the compass rose withthe airplane symbol and the VORcourse deviation bar in the center.

The expanded VOR mode shows 80degrees of the compass rose withthe airplane symbol and the VORcourse deviation bar at the bottom.

This VOR information shows on thedisplay:

• VOR course deviation• TO/FROM annunciation• System source annunciation• Station identification or frequency• Station bearing• Selected course• DME distance.


• Ground speed• True airspeed• Wind speed and direction.

VOR Display

Centered VOR Expanded VOR


November 2000 5-13

PFD/ND

The APPROACH (APP) mode showsin a centered or expanded displayformat.

The centered APP mode shows 360degrees of the compass rose withthe airplane symbol and the localizerdeviation bar in the center.Glideslope deviation shows on theside of the display.

The expanded APP mode shows 80degrees of the compass rose withthe airplane symbol and the localizerdeviation bar at the bottom.

This ILS information shows on thedisplay:

• Localizer deviation• Glide slope deviation• System source annunciation• Station identifier or frequency• Selected runway heading• DME distance.


• Ground speed• True airspeed• Wind speed and direction.

Centered APP Expanded APP

Approach Display

5-14 November 2000

PFD/ND

MAP

The map mode shows in a centeredor expanded display format.

The centered map mode shows 360degrees of the compass rose withthe airplane symbol in the center.

The expanded map mode shows 80degrees of the compass rose withthe airplane symbol at the bottom.

This map information shows on thedisplay:

• Airplane track and heading• Flight plan waypoints• Flight plan path lines• Active waypoints• Airports• Navigation aids• Distance to go• ETA• Vertical path deviation• Trend vectors.

Map Display

Centered Map Expanded Map


November 2000 5-15

PFD/ND

PLAN

The flight crew uses the plan mode tocreate, view or change a flight plan.The display is a north up display. Theairplane symbol shows presentposition and FMC track.

Plan Display

Plan Mode

5-16 November 2000

Engine Display

SIDE-BY-SIDE ENGINE DISPLAY

The side-by-side engine displaynormally shows on the upper centerdisplay unit. It can also show on thelower center display unit or theinboard display units.

This engine information shows onthe side-by-side engine display:

• N1• Thermal anti-ice indication• EGT• N2• Fuel flow/fuel used• Fuel quantity• Oil pressure• Oil temperature• Oil quantity• Engine vibration• Hydraulic pressure• Hydraulic quantity• Crew alert messages• Autothrottle limit message• Thrust mode• Total air temperature.

Side-By-Side Engine Display

Engine Display (Side-By-Side)

0

12 3.758

4

12

84

03.76

87.7 87.7

TAI TAI

START VALVEOPEN

OIL FILTERBYPASS

LOW OILPRESSURE

START VALVEOPEN

OIL FILTERBYPASS

LOW OILPRESSURE

1

OIL Q %

05

2 34

1

200

100

0

10050

0

75

05

2 34

200

100

0

10050

0

75

OIL T

OIL P

7600

1

7600

224

CTR

000

FF/FULB X 1000

N2

X-BLD STARTEGT

1N

10

8

4

0

26

HYD Q %RF RF

B

02

3 4

102

3 4

1

A

HYD P

VIB

FUEL LB

4

10

80

26

CRZA/T LIM

70 60

96.0

-12cTAT

87.787.7

663663

REV


November 2000 5-17

Engine Display

OVER/UNDER ENGINE DISPLAY

The over/under engine displaynormally shows the engineinformation on two displays. Theprimary engine display normallyshows on the upper center displayunit. The secondary engine displaynormally shows on the lower centerdisplay unit.

This engine information shows onthe primary engine display:

• N1• Thermal anti-ice indication• EGT• Fuel quantity• Crew alert messages• Autothrottle limit message• Thrust mode• Total air temperature.

This engine information shows onthe secondary engine display:

• N2• Fuel flow/fuel used• Oil pressure• Oil temperature• Oil quantity• Engine vibration.

Engine Display

Engine Primary Engine Secondary

5-18 November 2000

Engine Display

COMPACTED ENGINE DISPLAY

The over/under engine displaynormally shows the engineinformation on two displays. Thecompacted display showsautomatically when the upper centeror the lower center display unit fails.

The engine information that showson the compacted engine display areall the primary and secondary engineinformation.

Compacted Engine Display

Compacted Display


November 2000 5-19

Systems Display

The systems display shows whenyou select SYS on the engine controlmodule. The systems display canshow on the lower center display unitor either inboard display unit.

This information shows on thesystems display:

• Hydraulic quantity• Hydraulic pressure• Brake temperature (option)• Flight control surface position

(option).

Systems Display

Systems Display

5-20 November 2000

BITE

Maintenance data shows on the flightmanagement computer controldisplay unit (FMC CDU.) Themaintenance data includes:

• CDS LRU faults• Engine exceedance information• Hardware and software

configuration information.

The display electronic unit (DEU)stores sixty-four flight legs of faults.

There are several CDS tests. AnFMC CDU menu permits access tothese tests. The tests include:

• DEU self test• DU loop status test• DU optical test.

The DEU is also the interface forBITE information from the EEC andthe APU.

FMC CDU Display

Display Electronics Unit (2)

Flight ManagementComputers (2)

EEC

APU

F Q I S

UPA

E NG N

N

I

I

S

S

>

>

E

XEDI

SDC

T/A

S

CFD

CMF

1/1NI DE XETIBTNAM I

<

<

<

<

>

<

< A D RS

Communications and Recording

November 2000 6-1

• Flight Interphone

• Service Interphone

• Flight and Ground Crew Call

• Passenger Address

• Audio/Video Entertainment

• VHF Communications

• HF Communications

• SELCAL

• Aircraft CommunicationsAddressing and ReportingSystem (ACARS)

• Voice Recorder

• Flight Data Recorder

• Aural Warning

• Electronic Clocks

• SATCOM

Features

DIGITAL AUDIO CONTROL

The digital audio control is a systemthat processes all audio informationto, from, and in the airplane.

HF COMMUNICATIONS(OPTIONAL)

The HF antenna is a new designbecause of the 737-600/-700/-800vertical stabilizer redesign.

AIRCRAFT COMMUNICATIONSADDRESSING AND REPORTINGSYSTEM (ACARS) (OPTIONAL)

ACARS is a digital data link thatsupplies communication between theairplane and ground operations withthe VHF radio.

6-2 November 2000

Flight Interphone System

The flight interphone system lets thecrew members in the flightcompartment communicate witheach other. It also connects with theaudio communication system andthe ground crew members.

There are three independentsystems, one for each flight crewstation and the observer station. Thecaptain system is shown on thegraphic.

The flight crew selects a system onthe audio control panel (ACP) totransmit or receive audio. These arethe systems that the pilot can select:

• Communication radios• Navigation receivers• Cabin interphone• Passenger address• Flight and service interphone.

When the pilot selects a system onthe ACP, the remote electronics unit(REU) sends audio from the handmicrophones, boom microphones oroxygen mask microphones to thatsystem. The REU also sends theaudio from the system to theheadsets and speakers.

The REU also integrates and sendswarning audio to the headsets andspeakers. The warning audio comesfrom these systems:

• Ground proximity warning system• Traffic alert and collision

avoidance system• Digital flight control system.

The interphone/radio push-to-talk(PTT) switches are on the controlwheels for use with the oxygen maskor boom microphones. The RADIO -INT switch on the audio control paneldoes a similar function.

Flight Interphone System

Remote Electronics Unit

D[]C[]B[]A[]

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

RTCA 00-16

TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

ATTENTION

WEIGHT 7.75 LBS

DATE MFD

REMOTE ELEC

SVR INT

DME 2

FLT INT

SVR INT

AAU CAPTF/OOBSEXT

ATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

MOD

Headsets

HeadphonesOxygen Masks

Control WheelMic Switch

Flight InterphoneSpeakers

Navigation

Communication

Passenger

Service Interphone

Voice Recorder

GPWS

DFCS

Radios

Receivers

External Power Panel

Address

TCAS

Hand Mics

Audio Control Panel (3)

INTERPHONE

SERVICE

NWW LIGHT

FLIGHT

ON

NORMALNOTIN USE

EXTERNALPOWER

CONN.

PILOT CALL

BOOMI/C

MASKR/T RV

NORM

ALT

SPKRMKR1-ADF-21-NAV-2

PAINTFLT

INTSERVHF1-VHF-2-VHF-3

w wwwwww

MIC SELECTOR

B


November 2000 6-3

Service Interphone

The service interphone system is forcommunication between thesepersonnel:

• Flight crew• Cabin attendants• Maintenance personnel.

They are in different areas aroundthe airplane.

Attendants use handsets at eachattendant station to communicate onthe service interphone system. Theflight crew selects service interphoneon the audio control panel.

The handsets send audio to theremote electronics unit. The REUamplifies the audio and sends it backto the handsets.

A toggle switch in the flightcompartment connects the externalservice interphone headset jacks tothe service interphone. Serviceinterphone headset jacks are inthese areas:

• External power panel• APU• Aft service door• EE compartment• Main wheel well• Underwing fueling station.

Service Interphone System

Handset (2)Attendant

Control WheelPTT Switch (2)

APUAft Service DoorEE CompartmentMain Wheel WellFueling Station

HeadsetsHeadphones

Oxygen Masks

Service InterphoneSwitch

1 2 34 5 67 8 9

0 #*

Hand MicsExternal Power Panel

INTERPHONE

SERVICE

NWW LIGHT

FLIGHT

ON

NORMALNOTIN USE

EXTERNALPOWER

CONN.

PILOT CALL

WINDOW

CEILINGENTRY

LIGHTING

Attendant Panel

OFF

ON

SERVICEINTERPHONE


D[]C[]B[]A[]

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

RTCA 00-16

TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

ATTENTION

WEIGHT 7.75 LBS

DATE MFD

REMOTE ELEC

SVR INT

DME 2

FLT INT

SVR INT

AAU CAPTF/OOBSEXT

ATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

MODBOOMI/C

MASKR/T RV

NORM

ALT


PAINTFLT


w wwwwww

MIC SELECTOR

B


6-4 November 2000

Flight and Ground Crew CallSystem

The flight and ground crew callsystem permits call signals betweenthese areas:

• Flight compartment and cabinattendant stations

• One cabin attendant station toanother cabin attendant station

• Flight compartment and groundcrew.

The system tells personnel to use theservice interphone.

The flight compartment can call acabin attendant station with theATTEND switch on the forwardoverhead panel. A pink light at theforward and aft exit locator signs turnon and there is a two-tone chimefrom the passenger address system.A cabin attendant can call anotherattendant station with the 5 push-button on the handset. The exitlocator pink light at the called stationcomes on and there is a chime fromthe passenger address system.

A cabin attendant pushes the 2 push-button on the handset to call the flightcompartment. A call light on theforward overhead panel comes onand there is a chime from the auralwarning module.

A crew member pushes the GRDCALL switch in the flightcompartment to call the ground crew.The switch is on the forwardoverhead panel. A horn in the nosewheel well comes on when the pilotsuse this switch.

The ground crew pushes the PILOTCALL switch on the external powerpanel to call the flight compartment.A call light on the forward overheadpanel comes on and there is a chimefrom the aural warning module.

Flight and Ground Crew Call System

Attendant Panel (2)

Attendant

Passenger

Exit Locator Sign (2)

Aural Warning

Ground CrewCall HornPassenger

Sign ModuleAddressAmplifier

Handset (2)

1 2 34 5 67 8 9

0 #*

WINDOW

CEILINGENTRY

LIGHTING

External Power Panel

__________

__________ _________

_____________ INTERPHONE

SERVICE

NWW LIGHT

FLIGHT

ON

NORMALNOTIN USE

EXTERNALPOWER

CONN.

PILOT CALL

CALLb

CALLGRD

ATTEND

Module


November 2000 6-5

Passenger Address System

The passenger address (PA) systemgives announcements and music tothe passenger compartment.

The pilots or cabin attendants canmake announcements. The pilotannouncements have the highestpriority. The pilots makeannouncements with themicrophones and the PA selectionon the audio control panel.

Attendant announcements havesecond priority. An attendant pushesthe eight push-button and the PApush-to-talk switch on a handset tomake announcements.

Prerecorded announcements fromthe tape reproducer have thirdpriority. Boarding music from thetape reproducer has fourth priority.

The PA amplifier sends the highestpriority audio to all the speakers inthe passenger compartment.

The PA amplifier decreases theoutput level of the audio when theengines are on.

The PA amplifier supplies audio forthe attendant area speakers throughthe remote electronics unit. Anattendant announcement mutes thisaudio to stop microphone feedback.

The PA amplifier also supplies thechimes. Chimes are superimposedover any audio.

Passenger Address System

SpeakersAreaAttendant

SpeakersLavatory

Tape Reproducer

Either+10 db-1

CALNORM

TEST

346D-2B


Control WheelPTT Switch (2)

HeadsetsHeadphones

Oxygen Masks

Passenger AddressAmplifier

Engine On

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

ATTENTION

WEIGHT 7.75 LBSDATE MFD

SVR INT

DME 2FLT INTSVR INT

AAU CAPTF/OOBS

RTCA 00-16TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

EXTATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

Handset (2)Attendant

1 2 34 5 67 8 9

0 #*

REMOTE ELEC

NOSMOKING BELTS

CALLb

CALLGRD

ATTEND

ON

AUTO

OFF

FASTEN

PassengerSign Module

Hand Mics

PassengerService UnitSpeakers

PA ControlStand Mic


BOOMI/C

MASKR/T RV

NORM

ALT


PAINTFLT


w wwwwww

MIC SELECTOR

B

6-6 November 2000

Audio/Video Entertainment(Optional)

Audio and video entertainmentsystems are optional equipment.

A typical audio entertainment systemhas these units:

• Audio reproducer• Main multiplexer• Seat electronics boxes• Passenger control units• Headsets.

A video entertainment system maybe added to the audio entertainmentsystem. The typical video systemhas these units:

• Video tape reproducer• Video monitors.

Audio from the video entertainmentsystem goes through the audioentertainment system.

The audio reproducer sends audio tothe main multiplexer. The multiplexerchanges the analog audio signals toa digital format and sends the digitalsignals to the seat electronics units.The passenger then selects theaudio channel with the passengercontrol unit. The passenger hearsthe audio in their headset.

The passenger address systemsends audio to the main multiplexer.Passenger address audio haspriority over all the entertainmentaudio.

Audio/Video Entertainment

MainMultiplexer

Audio

Video

PassengerAddressAmplifier

A B C

Audio Reproducer

SEB BRKRCTT

Seat Electronics Unit

+10 db-1

CALNORM

TEST

346D-2B

Reproducer

PassengerControl Unit

Video MonitorVIDEO CASSETTE PLAYER EVP-90B

videoHi8


November 2000 6-7

VHF Communication System

The very high frequency (VHF)communication system supplies lineof sight voice and datacommunications from air-to-groundor air-to-air.

A dual VHF communication systemis basic. A third VHF transceiver isavailable as an option.

A radio tuning switch, on a radiocommunication panel (RCP) selectsone of the transceivers. Thefrequency selectors select thedesired frequency. This shows onthe liquid crystal display standbyfrequency window. The frequencytransfer switch moves the standbyfrequency to the active frequency.The RCP sends tuning data to theselected transceiver.

The transceiver sends and getsaudio and data from the antenna.

The remote electronics unit doesthese functions for transmissionswith inputs from the audio controlpanel:

• Microphone selection• Headphone or speaker

monitoring• PTT.

The aircraft communicationsaddressing and reporting system(ACARS) controls data to an optionalthird VHF communication system.ACARS is an optional system. Wheninstalled, ACARS uses the VHFtransceiver to get and send digitaldata to and from a ground station.

VHF Communication Systems

VHF Transceiver (3)

MIC

PHONE

CONTROL

VHF-900

ANTENNA

LRU

VHF Antenna (3)

Radio Communication Panel (3)

ACARS

Remote

ManagementUnit

Electronics Unit

HeadsetsHeadphones

Oxygen Masks

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

ATTENTION


SVR INT

DME 2FLT INTSVR INT

AAU CAPTF/OOBS

RTCA 00-16TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

REMOTE ELEC

EXTATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLTOFF TEST

HF2

VHF3VHF2

HF1 AM

STANDBY

VHF1

ACTIVE

Hand Mics


FDAU

SELCALDecoder

BOOMI/C

MASKR/T RV

NORM

ALT


PAINTFLT


w wwwwww

MIC SELECTOR

B

6-8 November 2000

HF Communication System

The high-frequency (HF)communication system is for long-range voice communications.

Each HF communication system hasthese units:

• HF transceiver• HF antenna coupler• Shared antenna.

A radio tuning switch on the radiocommunication panel (RCP) selectsone of the transceivers. Thefrequency selectors select thedesired frequency. This shows onthe liquid crystal display standbyfrequency window. The frequencytransfer switch moves the standbyfrequency to the active frequency.The RCP sends tuning data to theselected transceiver.

The transceiver sends and gets theaudio.

The remote electronics unit doesthese functions with audio controlpanel selections:

• Microphone selection• Headphone and speaker

monitoring• PTT.

The antenna and the antennacouplers are in the vertical stabilizer.

The antenna coupler matches theimpedance of the antenna to theimpedance of the transceiver. Thecoupler tunes when you first key theHF transmitter.

HF Communication Systems

HF Transceiver (2)

HF Antenna

SQL/LAMP TEST

LRU FAIL

KEY INTERLOCK

CONTROL INPUT FAIL

PHONE MICHFS-700

Remote ElectronicsHeadsets

HeadphonesOxygen Masks

Coupler (2)

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

ATTENTION


SVR INT

DME 2FLT INTSVR INT

AAU CAPTF/OOBS

RTCA 00-16TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

REMOTE ELEC

EXTATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

Hand Mics

HF Antenna

SELCAL

FDAU

Decoder

Radio Communication Panel (3)

OFF TEST

HF2

VHF3VHF2

HF1 AM

STANDBY

VHF1

ACTIVE


Unit

BOOMI/C

MASKR/T RV

NORM

ALT


PAINTFLT


w wwwwww

MIC SELECTOR

B


November 2000 6-9

SELCAL (Optional)

The selective calling (SELCAL)system monitors all communicationradios on the airplane. The systemalerts the flight crew when it gets aground call with the correct airplanecode. This reduces the flight crewworkload because they do not haveto continuously listen to the airlinecommunication frequencies.

The SELCAL decoder gets audiosignals from the VHF and HFcommunication systems. TheSELCAL decoder gives signals to theflight crew if the signal received hasthe airplane unique SELCAL code.The airplane unique SELCAL codecomes from the SELCAL codingswitch.

When the SELCAL gets a call, thesethings occur:

• Call light on the audio controlpanel

• SELCAL chime from the auralwarning module.

When the flight crew selects a PTTfor the applicable radio, the lightgoes off and the system resets.

SELCAL System

HF Transceiver (2)

SQL/LAMP TEST

LRU FAIL

KEY INTERLOCK

CONTROL INPUT FAIL

PHONE MICHFS-700

SELCALCoding Switch

VHF Transceiver (3)SELCAL

Aural Warning

Decoder

Alert/Reset

MIC

PHONE

CONTROL

VHF-900

ANTENNA

LRU

Module

D[]C[]B[]A[]

SERIAL NO.

AAZ

ENV CAT

ONICS UNIT

RTCA 00-16

TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

ATTENTION

WEIGHT 7.75 LBS

DATE MFD

REMOTE ELE

SVR INT

DME 2FLT INTSVR INT

AAU CAPTF/OOBSEXTATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

MOD

Remote Electronics

Select AuralWarningRelay


Unit

BOOMI/C

MASKR/T RV

NORM

ALT


PAINTFLT


w wwwwww

MIC SELECTOR

B

6-10 November 2000

ACARS (Optional)

The aircraft communicationaddressing and reporting system(ACARS) gives a high-speed digitaldatalink between the airplane andground facilities. ACARS reducesflight crew workload by automaticallytransmitting and receiving data.

This is the type of data the ACARStransmits and receives:

• Airplane identification• Flight identification• Out of gate, off the ground, on

the ground, into the gate (OOOI)reports

• Delay reports• Fuel reports• Weather• Airplane operating data.

ACARS also provides voicetelephone patch communicationbetween the airplane and groundtelephone circuits. It uses VHF radio,airline land lines, ARINC lines, andtelephone systems.

The main ACARS component is theACARS management unit (MU). TheMU uses program pins and aprogram switch module for airlineidentification and the proximityswitch electronics unit (PSEU) todefine the OOOI event parameters.The MU uses VHF transceiver 3 toreceive and transmit data.

The flight crew controls the systemwith an interactive display unit (IDU)or the control display unit (CDU).

The flight crew uses the multi-purpose printer to print ACARSreports stored in the MU.

A call light in the flight compartmentcomes on, and there is a chime whenACARS receives a voice requestfrom a ground station. The IDUshows the requested voicecommunication frequency to theflight crew. The flight crew can usethe IDU to tune the VHF transceiverto make a voice call to the ground.

Aircraft Communications Addressing and Reporting System (ACARS) (Optional)

Multipurpose Printer

Management UnitACARS

Interactive Display Unit

StationData LineRemote

Data

Frequency

Airline Land Lines

Telephone SystemDataLine Control

VHF 3 Antenna

Selected Voice

StationVoice

Airline DispatchCommunicationsARINCARINC ARINC

DEPDES

FLTFUEL

MENU CLEAR

YOX ENTER

A B C D E

F G H I J

K L M N O

P Q R S T

U V WX Y Z

1 2 3

4 5 6

7 8 9

0 -+ -

PAPER

EMPTY

FULL

VHF Transceiver

Program Pins

Program Switch Modules

Proximity Switch Electronics Unit

Satellite Data Unit

Flight Management Computer SystemFlight Data Acquisition UnitAirshow Digital Interactive Unit


November 2000 6-11

Voice Recorder System

The voice recorder makes acontinuous record of the last 120minutes of flight crew communi-cations. It erases automatically sothat only the last 120 minutes are inmemory.

The voice recorder records fouraudio channels. These are the fourchannels:

• Captain microphone• First officer microphone• First observer microphone• Area microphone on the voice

recorder control panel.

Microphone inputs from the captain,first officer, and first observer go tothe remote electronic unit (REU).The REU amplifies the audio andsends it to the voice recorder. Theaudio from the area microphone isamplified at the microphone andgoes directly to the voice recorder.

The test switch on the control paneldoes a functional check of thesystem.

The bulk ERASE switch on thecontrol panel erases all stored audioin the voice recorder. The switcherases the audio only when theairplane is on the ground with theparking brake on.

An underwater locator beacon is onthe front of the voice recorder.

Voice Recorder System

g

r

HEADPHONESTATUS

ERASE TEST

COCKPIT VOICE RECORDER MICROPHONE MONITOR

Voice Recorder

Voice Recorder Control Panel

Test

Erase

Audio Channel 4

Audio Channel 3

Audio Channel 1

Audio Channel 2

Parking Brake

Remote Electronic

SERIAL NO.

AAZ ENV CAT

ONICS UNIT

ATTENTION


SVR INT

DME 2FLT INTSVR INT

AAU CAPTF/OOBS

RTCA 00-16TSO C50c

BOEING P/N

B2AKXXXXFX

AVTECH P/N

REMOTE ELE

EXTATT

ADJDME 1 ADJPA SENS

PA STAUDIO POT 1

PA GAIN

AUDIO POT 2

SVR

HDPHFLT

SVR

HDPHFLT

Clock

Headphones

Oxygen Masks

Hand Mic

Set and GroundSensing Relays

Unit

6-12 November 2000

Flight Data Recorder System

The flight data recorder system(FDRS) records the last 25 hours offlight parameters in a crash proofcontainer. It records parameters thatare required by regulatory agenciesand requested by the airline.

The flight data recorder systemoperates automatically when eitherengine is operating or the airplane isin the air.

A flight recorder panel shows thestatus of the flight recorder system. Ifthere is a system fault, an amberOFF light shows. The OFF light alsocomes on if the system is off.

The flight recorder panel also has aTEST/NORMAL switch. When theTEST/NORMAL switch is in theTEST position, the recorder receivespower on the ground.

Airplane systems send digital,discrete, and analog data to the flightdata acquisition unit (FDAU). TheFDAU formats the data. The FDAUsends the data to the flight datarecorder (FDR).

The FDR records the data in a fireand crash resistant LRU. Anunderwater locator beacon is on thefront of the FDR.

An optional FDAU can also collectdata for the airplane conditionmonitoring system (ACMS). TheACMS is an optional system. TheFDAU sends the ACMS data to aquick access recorder or to a diskettein its internal disk drive.

Flight Data Recorder System

Flight Data Recorder

Flight Data Acquisition Unit (FDAU)

Printer

a

FLIGHT RECORDER

TEST NORMAL

OFF

NO 1 NO 2

MACHAIRSPEEDWARNING

TEST

Discrete Flight DataAnalog Flight DataDigital Flight Data

AccelerometerData LoaderControl Panel

115V AC

System TestPlug/Connector

DATA LOAD SELECT

DFDAU

ACMSNORM

Program Switch Module

Control Wheel Position Sensors (2)Control Column Position Sensors (2)

Rudder Pedal Position SensorRudder Position Transmitter

Aileron Position Transmitters (2)Elevator Position Transmitters (2)

Flight Recorder/Mach AirspeedWarning Test Module

FDAUStatus Relay

Quick Access Recorder


November 2000 6-13

Aural Warning System

The aural warning system tells theflight crew of incorrect airplanesystem conditions with auralindications. The system alsoprovides the aural indication forSELCAL and crew calls.

The aural warning module monitorsseveral airplane systems. Theairplane systems send a signal to theaural warning module if they detectan unsafe condition.

The aural warning module suppliesthese aural indications:

• Bell for a fire• Intermittent horn for a unsafe

takeoff configuration or cabinaltitude too high

• Steady horn for unsafe landingconfiguration

• Clacker for overspeed• Wailer for autopilot disconnect• Chimes for crew call and

SELCAL.

For an unsafe condition, there arealso visual indications. The cautionlights and the fire warning lights arethe visual indications. These lightscome on when airplane systemsdetect an unsafe condition.

There are other independent warningsystems. These systems are not partof the aural warning system:

• The ground proximity warningsystem

• The traffic collision andavoidance system

• The digital flight control system.

Aural Warning System

Takeoff Warning SystemCabin Altitude Warning SystemLanding Gear Warning System

Digital Flight Control SystemMach Warning System

Fire Warning SystemSELCAL System

Crew Call System Aural Warning

OVHT/DETFUEL

APUIRS

FLT CONT ELEC

aa

aPUSH TO RESET

CAUTIONMASTER

BELL CUTOUT

WARNFIRE

r

a

ANTI-ICE ENG

HYD OVERHEAD

DOORS AIR COND

BellHornClackerWailerChimes

a

aPUSH TO RESET

CAUTIONMASTER

BELL CUTOUT

WARNFIRE

r

Module

6-14 November 2000

Electronic Clocks

There are two clocks in the flightcompartment, one on the captainand the other on the first officerinstrument panel.

Each clock shows this information:

• Time• Date• Elapsed time in hours and

minutes• Chronograph time in minutes and

seconds.

The captain clock sends time on anARINC 429 bus to the flight dataacquisition unit (FDAU), the flightmanagement computer, and thevoice recorder.

Electronic Clocks

FDAU

Clock

ON VALIDPWR FMC

Flight ManagementComputer

Voice Recorder

50

40

SET

ETHLD

RUNET CHR

MOYRDAY

30

10

20

60UTC

MAN

TIME/DATECHR

TIME

RESET


November 2000 6-15

Satellite Communication(SATCOM) System (Optional)

The SATCOM system sends andgets data and voice messages. Thesystem uses satellites as relaystations for long distancecommunication. SATCOM is morereliable than HF communicationbecause it is not affected byatmospheric conditions.

The system is the satellite network,the ground earth station (GES), andthe aircraft earth station (AES).

The satellite network relays radiosignals between the AES and theGES. Each GES is a fixed radiostation that interfaces withcommunication networks throughground links and the aircraft earthstations through the satellite. TheAES is the SATCOM system on theairplane that interfaces with variousonboard communication systemsand the ground earth stations.

AIRCRAFT EARTH STATIONDESCRIPTION

The basic SATCOM configuration isa high-gain system with high-gainside-mounted antennas.

The satellite data unit (SDU) is theinterface between all other relatedairplane systems and the SATCOMsystem. The radio frequency unit(RFU) changes the signal from theSDU to an L-band signal for the highpower amplifier (HPA). The HPAsupplies adequate radio frequencypower to the antenna. The low noiseamplifier (LNA) and diplexer are oneunit. The diplexer couples transmitsignals from the HPA to the antenna.It also couples signals from theantenna to the LNA. The LNAamplifies the low level L-band signalfrom the antenna. The SDU sendsdirectional control signals to thebeam steering unit (BSU). The BSUelectronically steers the antenna to

point the beam at the desiredsatellite.

The AES interfaces with the ACARSMU that send and get datamessages. The AES also interfaceswith the passenger telephonesystem and the remote electronicsunit for voice call audio and controlsignals.

SATCOM System

REU

SDU

RFU High Power

BSULNA/Diplexer

LNA/Diplexer

Ground Earth Station (GES)

Aircraft Earth Station (AES)

Amplifier

SatelliteNetwork

ACARSMU

Combiner

High

Relay

HighGainAntenna

BSU

HighGainAntenna

PassengerTelephoneSystem

Power

Navigation

November 2000 7-1

• Air Data Inertial ReferenceSystem

• VHF Omnidirectional Range(VOR) System

• Marker Beacon System

• Instrument Landing System

• Distance MeasuringEquipment

• Automatic Direction FinderSystem

• Radio Altimeter System

• Air Traffic Control System

• Traffic Alert and CollisionAvoidance System

• Weather Radar System

• Ground Proximity WarningSystem

• Global Positioning System

• Head-Up Display System(HUD)

Features

NEW AVIONICS

The 737-600/700/800/900 usessome new avionics componentssuch as the air data inertial referenceunit (ADIRU). The ADIRU puts the airdata computer and the inertialreference unit together in a singleunit. This saves space and weight.

UPGRADED AVIONICS

All navigation systems now useARINC specification 429 for digitalcommunication between units andsystems. This results in increasedreliability, fewer components, andfewer wires.

SATELLITE NAVIGATION

The 737-600/700/800/900 offers thenewest in navigation systems, theglobal positioning system (GPS).GPS gives improved navigationaccuracy along the flight plan. Thissaves fuel and improves the airplaneon-time performance.

COMMON COMPONENTS

The 737-600/700/800 uses manynavigation system units that arecommon with the 777, 747-400, 767,757, and 737-300. This reduces thecost of maintenance and spares.

HEAD-UP DISPLAY SYSTEM

The head-up display system useselectronics and optics to calculateand display flight and guidancesymbols. The symbols project onto atransparent glass screen in theforward field of view of the pilot. Thesymbols overlay and opticallycombine with the outside viewthrough the windshield.

7-2 November 2000

Air Data Inertial ReferenceSystem

The air data inertial reference system(ADIRS) has two separate functionsin a single line replaceable unit(LRU). The two functions use thesame power supply. All otheroperations are separate. The air datafunction is active when electricalpower is on. The inertial referencefunction is active when the pilotsselect it on.

AIR DATA FUNCTION

The air data modules (ADMs) givepitot and static pressure data to theair data inertial reference unit(ADIRU). The ADMs convertpressure to digital data. The total airtemperature (TAT) probe gives TATto the ADIRU. The angle-of-attack(AOA) sensors give AOA data to theADIRU.

The ADIRU uses the ADM, TAT, andAOA data to calculate these values:

• Altitude• Computed Airspeed• Mach• Air temperature• Angle-of-attack• Baro-corrected altitude• Maximum allowable airspeed• True airspeed• Altitude rate• Static air temperature.

The ADIRU sends these values ondigital data buses to the systems thatuse calculated air data values.

The alternate pitot probe and thealternate static ports send thepressure to standby instruments.The cabin pressure control systemalso uses alternate static pressure.

Air Data Inertial Reference System - Air Data Function

ADM

ADM

ADM

ADM

Right

Left

F/O Pitot Probe

Capt Pitot Probe

Alt Pitot Probe

AOA SensorTAT Probe Capt

StaticPort

CaptStaticPort

F/OStaticPort

F/OStaticPort

AltStaticPort

AltStaticPort

ToStbyInst

To Stby

To User Systems andCabinPress

AOA Sensor

Airspeed

ADIRU

ADIRU

Navigation

November 2000 7-3

Air Data Inertial ReferenceSystem

INERTIAL REFERENCEFUNCTION

The ADIRS inertial referencefunction uses laser gyros andaccelerometers to measure airplanemovement. The inertial referencefunction uses the gyro andaccelerometer data to calculatethese values:

• Attitude (pitch, roll, yaw)• Position (latitude, longitude)• True heading• Magnetic heading• Inertial velocity vectors• Linear accelerations• Angular rates• Track angle• Wind speed and direction• Inertial altitude• Vertical speed• Ground speed

• Drift angle• Flight path angle.

The inertial reference function hasthese components:

• ADIRUs (2)• Mode select unit (MSU)• Inertial system display unit

(ISDU)• IRS transfer switch.

You use the MSU to select the modeof operation for the ADIRU inertialreference function. You can selectthese modes:

• Off• Align• Navigate• Attitude.

Before the ADIRUs can operate inthe navigation mode, they must doan alignment. The airplane must notmove during the alignment. You canuse the flight management computer(FMC) control display unit (CDU) or

the ISDU to put the airplane presentposition into the ADIRU.

Inertial reference data shows on thecommon display system (CDS)display units, the HUD, and on theradio magnetic indicator (RMI).Navigation, autoflight and otherairplane systems also use inertialreference data.

The IRS transfer switch selects theADIRU that gives inertial referencedata to the display system. When theswitch is in the NORMAL position,the left ADIRU gives information tothe captain displays and the rightADIRU gives information to the firstofficer displays. You move the switchto BOTH ON LEFT or BOTH ONRIGHT to cause one ADIRU to giveinformation to all displays.

Air Data Inertial Reference System - Inertial Reference Function

Mode Select Unit

ADIRU (2)

FMC CDU Ground Proximity

Weather Radar

Flight Management

Flight Control

Radio Magnetic

CDSDisplayUnits (2)

IRS DISPLAY

DSPL SEL

Transceiver

Inertial SystemDisplay Unit

IRS TransferSwitch

IRSL R

ALIGN ON DC

DC FAILFAULT

ALIGN ON DC

FAULT

OFF

NAVALIGN

DC FAIL

ATT OFF

NAVALIGN

ATT

TCASComputer

Autothrottle

Stall

Anti-Skid

Flight Data

Indicator

Warning Comp

Computer

Yaw Damper

AutobrakeControl Unit

Computer (2)

Acquisition Unit

Computer

HG2050 ADIRU

VOR

VOR

ADF ADF

HDG

CDS DisplayElectronic Unit

HUD Computer

Management

7-4 November 2000

VHF Omnidirectional Range(VOR) System

The VHF omnidirectional range(VOR) system gives bearinginformation to ground stations. Thepilots and the airplane systems usethis information.

The pilots use the navigation controlpanel to tune the VOR receiver.

The VOR system receives thesignals from the ground station andcalculates magnetic bearing to thestation.

These units use the VORinformation:

• Flight control computer (FCC)• Flight management computer

(FMC)• Common display system display

electronic unit (CDS DEU).• Radio magnetic indicator (RMI)• Flight data acquisition unit

(FDAU)• Head-up display system (HUD).

Magnetic bearing shows on the radiomagnetic indicator (RMI) and on thecommon display system (CDS)display units.

The CDS DEUs use the selectedcourse from the DFCS mode controlpanel to calculate VOR coursedeviation.

The VHF NAV transfer switch selectsthe VOR data that shows on the CDSdisplay unit. In the NORMALposition, VOR 1 data shows on thecaptain display unit and VOR 2 datashows on the first officer display unit.You move the switch to BOTH ON 1,or BOTH ON 2 to cause one VORreceiver to give data to the captainand first officer.

The VOR receivers send audio fromthe VOR station to the remoteelectronics unit (REU). The REUsends the audio to the flightcompartment speakers and pilotheadsets.

VHF Omnidirectional Range (VOR) System

NavigationControl Panel

MKR

TEST

DATA IN

VOR

VOR Receiver (2)

Flight Management

DFCS ModeControl Panel

AAU OBS F/O CAPT

ATTENTION

MOD A B C D

Flight ControlComputer

VHF NAVTransfer Switch

RemoteElectronics Unit

NORMAL

VHF NAV

ON 1

BOTH

ON 2

BOTH

VOR/LOCAntenna

Flight Data

Computer

Acquisition Unit

Radio MagneticIndicator


VOR

VOR

ADF ADF

HUD Computer

HDG

Navigation

November 2000 7-5

Marker Beacon

The marker beacon system givesaural and visual indications in theflight compartment as the airplaneflies over a marker beacontransmitter.

Marker beacon transmitters are onflight paths and runway approachpaths. The transmitter sends anarrow, vertical radio frequencybeam with an audio tone. Markerbeacon transmitters on runwayapproach paths send one of threedifferent audio tones.

As the airplane flies over the beam,the marker beacon system receivesthe audio tone. The marker beaconsystem then sends the aural andvisual indications to the commondisplay system, flight data acquisitionunit (FDAU), and the head-up display(HUD) system.

Each VOR receiver has a markerbeacon module. The marker beaconfunctions only in VOR receiver 1.

Marker Beacon System

Display

MKR

TESTDATA IN

VOR

VOR

Marker BeaconAntenna

Receiver 1


AAU OBS F/O CAPT

ATTENTION

MOD A B C D

BeaconMarker

AntennaAirway

Distance from end of runwaydifferent for each location

Intersection

CDS Display Unit (2)

Flight Data

ElectronicUnit (2)

Acquisition Unit

HUD Computer

7-6 November 2000

Instrument Landing System

The instrument landing system (ILS)gives precision approach guidanceon instrument approaches. The ILSgives position information to theglidepath and runway center line.

Two ILS systems are on the airplane.Each system operates the same.

The ILS system is active when a pilotselects an ILS frequency on thenavigation control panel. The controlpanel also sends course informationto the multi-mode receivers.

The multi-mode receivers calculateup and down glidepath deviationfrom the signal it receives from theglide slope antenna. They calculateleft and right deviation from thesignal they receive from the localizerantennas.

The multi-mode receivers use theVOR/ localizer antenna on thevertical stabilizer until the flightcontrol computer (FCC) changes themulti-mode receivers to the localizerantenna. This happens on approach.

ILS deviation shows on the CDSdisplay units, the head-up display,and on the standby attitude indicator.

These units use ILS information:

• Flight control computers (FCCs)• Standby attitude indicator• Ground proximity warning unit

(GPWS)• Flight management computer

(FMC)• Flight data acquisition unit

(FDAU)• Common display system display

electronic units (DEUs)• Head-up display (HUD)

computer.

ILS audio goes to the remoteelectronics unit (REU). The REUsends audio to the flightcompartment speakers andheadsets.

Instrument Landing System

Glide Slope

Localizer

VOR/

ILS Relay (2)

Multi- Mode

Flight Control

Ground

VALIDON

FMCPWR

Antenna

Remote

LocalizerAntenna

Antenna Electronics Unit

Flight Data

NavigationControl Panel

Computer B AcquisitionUnit

IntegratedFlight SystemsAccessory Unit

Flight ControlComputer A

StandbyAttitudeIndicator

FlightManagementComputer

ProximityWarningComputer

AAU OBS F/O CAPT

ATTENTION

MOD A B C D


MMR RECEIVER

MMR FAULTBUS IN FAILTEST ANT

TEST OK

TEST

Receiver (2)

HUD Computer

Navigation

November 2000 7-7

Distance Measuring EquipmentSystem

The distance measuring equipment(DME) system gives the pilotsdistance to a DME ground station.

Two DME systems are on theairplane. Each system operates thesame.

These units use the distanceinformation:

• Flight control computers (FCCs)• Flight data acquisition unit

(FDAU)• Display electronic units (DEUs)• Flight management computer

(FMC)• Head-up display (HUD)

computer.

The pilot can tune one DME stationwith the navigation control panel.This DME distance shows on theCDS display units. The FMC, HUDand the FCC also use this distance.

The FMC can tune up to four DMEstations at the same time. The FDAUand the FMC use these DMEdistances.

DME audio goes to the remoteelectronics unit. The pilots can hearthe audio on the flight compartmentheadsets and speakers.

Distance Measuring Equipment System

Navigation DMEInterrogator 1

Flight Control

VALIDONFMCPWR

Control Panel

Antenna

CDSDisplay Unit

Flight DataAcquisition Unit

Computer A

Flight ManagementComputer


AAU OBS F/O CAPT

ATTENTION

MOD A B C D


HUD Computer

7-8 November 2000

Automatic Direction FinderSystem

The automatic direction finder (ADF)system is a navigation aid thatreceives radio signals from a groundstation. The ADF calculates bearinginformation to a ground station. It canalso give audio to the pilots.

The audio is a station identifier or abroadcast from a radio station. SomeADF stations also supply weatherinformation.

The ADF system has thesecomponents:

• ADF receiver• Control panel• Combined loop and sense

antenna.

You can tune the ADF receiver toreceive and calculate bearing to anyradio transmitter with a frequencybetween 190 and 1750 kHz. Bearingshows on the radio magneticindicator (RMI), the HUD, and on thecommon display system displayunits. The receiver sends audio tothe remote electronics unit (REU).


Automatic Direction Finder System

ADF Control Panel

Ground

ADF Receiver

Radio Magnetic

ADF

CDS Display Unit

Antenna

Radio Station

ADF Antenna

AAU OBS F/O CAPT

MOD A B C D


IndicatorVOR

VOR

ADF ADF

HDG

HUD Computer

Navigation

November 2000 7-9

Radio Altimeter System

The radio altimeter (RA) systemgives the pilots and airplane systemsthe altitude of the airplane above theground. The RA system operatesfrom 0 to 2500 feet.

The system has two transceivers.Each transceiver has a transmitantenna and a receive antenna. Thetransmit antenna sends a signal tothe ground which comes back to thereceive antenna. The transceiveruses the time between transmissionand reception to calculate thealtitude above the ground. Radioaltitude shows on the CDS displayunits when radio altitude is 2500 feetor less.

These units use radio altitude:

• Flight control computers (FCCs)• Autothrottle computer• Display electronic units (DEUs)• Traffic alert and collision

avoidance system (TCAS)computer

• Ground proximity warningcomputer (GPWC)

• Flight data acquisition unit(FDAU)

• Head-up display (HUD)computer.

Each pilot can set a radio minimumsaltitude on the EFIS control panel.The radio minimums shows on theCDS display unit, and on the HUD.When the radio altitude is equal to orless than the radio minimums, theradio minimums and radio altitudechange color and size, andmomentarily flash.

Radio Altimeter System

Transceiver (2)Radio Altimeter TCAS Computer

Transmit

ReceiveAntenna

Flight DataGround Proximity

AntennaEFIS Control Panel (2)

Auto ThrottleComputer

AcquisitionUnit

Warning Computer

Flight ControlComputer


VOR


CTR TFC

RST STD

ADF 2

OFF

VOR 2

6403205

10 1608020

40

BAROHPAIN

MTRS

PLNMAP

APP

ADF 1

OFF

RADIOMINS

BAROFPV

VOR 1

HUD Computer

7-10 November 2000

Air Traffic Control System

The air traffic control (ATC) systemhas the airborne components thatthe TCAS computers and the groundfacilities use to track the airplanemovement.

The ATC transponder replies tointerrogation signals from the groundand from TCAS airplanes. The replyto most ground stations is airplanecode (mode A) or airplane altitude(mode C).

Selective calling (mode S) groundstations enhance the operation of theATC system because it adds adiscrete interrogation capability anda data link feature.

You use the ATC control panel to setthe airplane code, select transponder1 or 2, and start an identificationpulse. The altitude source selectswitch on the control panel selectsthe ADIRU that supplies altitude tothe transponder.

Only one ATC transponder is activeat a time. Antenna switches connectthe ATC antennas to the activetransponder.

The ATC transponder also workswith the traffic alert and collisionavoidance system (TCAS).

Air Traffic Control System

Bottom

Top ATC/Mode S

ATC Control Panel

Antenna

TCAS

ATC

Antenna Location

Computer

ADIRU (2)

ATC/Mode S

Transponders (2)

Switch

AntennaSwitch

MODE S TRANSPONDER

A

A

A

Navigation

November 2000 7-11

Traffic Alert and CollisionAvoidance System

The traffic alert and collisionavoidance system (TCAS) givesaural and visual indications to theflight crew. The indications areadvisories. The traffic display showsother airplanes and possible collisionconditions.

TCAS uses the ATC/Mode Stransponder system to send TCASdata to other TCAS airplanes.

The TCAS system has these units:

• TCAS computer• Top directional antenna• Bottom directional or omni-

directional antenna• Mode S ATC transponders (2)• ATC control panel.

TCAS gives two types of advisoriesto the pilots. One type is the trafficadvisory (TA) which tells of otherairplanes in the area. The other typeof advisory is the resolution advisory(RA). The RA gives the pilotsdirections to prevent a collision.

The TCAS computer sends data tothe DEUs and the HUD Computer.You push the traffic button on theEFIS control panel to show thelocation and track of other airplaneson the display units. The displayunits also show the pilots how tochange or maintain vertical speed toprevent a collision. TCAS sendsaural alerts to the flight compartmentthrough the remote electronics unit.

The ground proximity warningcomputer (GPWC) alerts have higherpriority than TCAS advisories. Whenboth computers give warnings at thesame time, you do not hear theTCAS indications.

The left ADIRU gives heading data tothe TCAS computer.

TCAS uses radio altitude to changethe range limits of advisories at lowaltitudes. Radio altitude also helpsTCAS to know if an airplane is on theground.

Traffic Alert and Collision Avoidance System

TEST

PASS

FAIL

LOWER ANT

ALT

CTL

UPPER ANT

TPR

MODE S TRANSPONDER

Top TCAS(Directional Antenna)

ATC Control Panel

AntennaSwitches

Bottom TCAS(Directional orOmnidirectionalAntenna)

TCASComputer

Ground Proximity

RadioAltimeter (2)

Left ADIRU


ATC Transponder (2)

AAU OBS F/O CAPT

MOD A B C D

ATTENTION

FDAU

Warning Computer

EFIS Control Panel (2)


HUD Computer

VOR


CTR TFC

RST STD

ADF 2

OFF

VOR 2

6403205

10 1608020

40

BAROHPAIN

MTRS

PLNMAP

APP

ADF 1

OFF

RADIOMINS

BAROFPV

VOR 1

7-12 November 2000

Weather Radar System

The weather radar system shows theweather conditions along the flightpath of the airplane. The pilots canchange the flight path to fly aroundbad weather conditions. The pilotscan also use the weather radarsystem as a navigational aid.

The weather radar transceiver sendsweather data to the common displaysystem display electronic units (CDSDEUs). The DEU shows weatherradar on the CDS display unit in fourcolors. The four colors define theseconditions:

• Green - light rainfall• Yellow - moderate rainfall• Red - heavy rainfall• Magenta - rainfall with

turbulence.

Push the WXR button on the EFIScontrol panel to show weather radaron the onside CDS display unit.

The pilots use the weather radarcontrol panel to set these functions:

• Mode of operation• Gain control• Antenna tilt angle.

The weather radar uses attitudesignals from the ADIRU to stabilizethe antenna scan.

The weather radar transceiver usesEFIS control panel range for displayof weather data on the display units.The pilots can set a different rangeon each EFIS control panel.

The weather radar system can showpredictive windshear (PWS)messages on the display units(DUs).

PWS uses inputs from the radioaltimeter and ADIRUs to detect a

windshear condition. PWS usesinputs from the PSEU, landing gearlever switch, and autothrottle switchpack to determine if the airplane is ina takeoff or approach mode.

PWS supplies information to theground proximity warning system(GPWS) computer for types ofmessages and message priority. TheGPWS computer supplies audioinhibit signals to the PWS function inthe weather radar transceiver.

These are the different PWSannunciations that show on the DUs:

• Windshear caution-yellow• Windshear warning-red• Windshear symbol bar-black and

red• Windshear attention bars-yellow.

Weather Radar System

TransceiverWeather Radar

Control PanelWeather Radar

CDS Display CDS Display Unit (3)Electronic Unit (2)

Weather RadarAntenna

EFIS Control Panel (2)

VOR


CTR TFC

RST STD

ADF 2

OFF

VOR 2

6403205

10 1608020

40

BAROHPAIN

MTRS

PLNMAP

APP

ADF 1

OFF

RADIOMINS

BAROFPV

VOR 1

ADIRU (2)

TEST

ANT FAILREC

STATUSLRU

ANT FAILXMIT

CONNTEST

Collins

RadioAltimeter (2)

PSEU

AUTO

GAIN

MAX

0

UP

DN

5 10

15

15

10TILT

5

MAP

WX RADARWX/TURBWX

TEST

Switch PacKAutothrottle

Lever SwitchLanding Gear Ground Proximity

Warning Computer

Navigation

November 2000 7-13

Enhanced Ground ProximityWarning System

The enhanced ground proximitywarning system (enhanced GPWS)gives the pilots aural and visualwarnings of unsafe conditions. Thewarnings continue until the pilotscorrect the condition. The systemoperates when the airplane is lessthan 2450 feet above the ground.

The enhanced GPWS displaysterrain forward of the airplane, andalso alerts the flight crew of earlydescent when landing. The groundproximity warning computer sendsterrain data to the common displaysystem to show on the navigationdisplays.

The GPWS uses inputs from theseunits to calculate warning conditions:

• Flap landing gear warning switch• Flap takeoff warning switch• Landing gear lever switch• Radio altimeter (2)• Flight management computer

(FMC)• Left air data inertial reference

unit (ADIRU)• Stall management yaw damper

(SMYD) computer• Multi-mode receiver (MMR) (2).

The FLAP, GEAR, and TERRINHIBIT switches on the groundproximity module prevent certainwarnings and displays. The FLAPINHIBIT switch sends a flaps downsignal to the GPWC. The GEARINHIBIT switch sends a landing geardown signal to the GPWC. TheTERR INHIBIT switch stops theterrain information on the navigationdisplays.

GPWS visual warnings show on thecommon display system (CDS)display units or on the belowglideslope annunciators. GPWSwindshear warning shows on theHUD.

GPWS aural warnings go throughthe remote electronics unit to thepilots headsets and speakers.

The GPWS prevents TCAS warningswhen both systems give a warning atthe same time.

Ground Proximity Warning System

Below G/SLight (2)

MMR (2)TCAS Computer

Flap Switches

SMYD

Flight Management

CDSDisplay unit

VALIDONFMCPWR

AAU OBS F/O CAPT

MOD A B C D

Radio Altimeter

Gear LeverSwitch

BELOW G/S

aP-INHIBIT

Computer

Left ADIRU

Ground ProximityWarning Computer



HUD Computer

Ground Proximity Module

NORMAL NORMAL

GEARINHIBITINHIBIT

FLAP

GROUND PROXIMITY

aINOP

SYS TEST

NORMAL

TERRINHIBIT

7-14 November 2000

Global Positioning System

The global positioning system (GPS)is a satellite radio aid for navigation.The GPS is part of a multi-sensornavigation system.

GPS uses navigation satellites togive accurate airplane position to theFMC and the flight crew.

The air data inertial reference units(ADIRUs) gives inertial referencedata to the multi-mode receiver(MMR). The MMR can use thisinformation to find the best satellitesduring system initialization. It alsouses the data for certain modes ofoperation.

The MMR calculates these values:

• Airplane latitude• Airplane longitude• Airplane altitude• Accurate time.

The FMC uses GPS data to helpcalculate airplane present position.The FMC CDU shows GPS presentposition. The pilots can turn off theuse of GPS data in FMC calculationswith the FMC CDU.

Global Positioning System

GPS

GPS Antenna (2)

VALIDONFMCPWR

FMC CDUFlight Management

DO NOT PAINT

Computer

ADIRU

MMR RECEIVER

MMR FAULTBUS IN FAILTEST ANT

TEST OK

TEST

Multi-Mode Receiver (2)

(2)

Navigation

November 2000 7-15

Head-Up Display System

OPERATION

The head-up display (HUD) systemshows flight and guidance symbols.The flight crew uses the HUD for lowvisibility takeoffs and CAT IIIaapproach and landings. They canalso use the system during normalweather conditions.

These components are in the HUDsystem:

HUD

• Computer• Drive electronics unit (DEU)• Annunciator panel• Control Panel• Overhead unit (OHU)• Combiner.

The HUD computer uses sensor datafrom other airplane systems tocalculate the symbols and theirposition on the combiner.

The DEU amplifies the symbol dataand sends it to the overhead unit.The DEU also contains the powersupplies for the DEU, OHU, andcombiner.

There is a cathode ray tube (CRT)and an optics projection assembly inthe overhead unit. Thesecomponents project the symbolsonto the combiner.

The combiner is a glass plateassembly. The assembly has twoground glass outer pieces with aspecial thin clear coating betweenthem. The special coating reflectsonly the green symbol displays fromthe CRT. The combiner opticallycombines the symbols with the viewthrough the captain windshield. Thecombiner also contains brightnesscontrols.

Status and warning annunciationsshow on the annunciator panel. Thepanel supplies the first officer withchanges in HUD status duringmanual ILS approach and landingoperations to CAT IIIa minimums.

The flight crew uses the control panelto select and show HUD modes andto enter data. Maintenancepersonnel use the panel to operatesystem BITE.

BITE

To do a system self-test, push TESTon the control panel or push the redreset switch on the front of thecomputer.

There is a fault ball indicator on thefront of the computer and the DEU.Normally, the indicator color is black.The color changes to white whenthere is a fault. The indicator resetsautomatically.


ENTER

6

32

5

1

4

7 8 9

0 TEST

SGH

DIM -BRT +CLRFAULT

G/S

RWY

STBY

MODE

Overhead Unit

AirplaneSensors

COMPUTERPATENT No.PROTECTED BY US

TESTCOMPUTERFAULT

HGS COMPUTERR

FLIGHT DYNAMICS

APCHWARN

AIII

FLARE

Control Panel

Combiner

Drive

Annunciator

HUD Computer

ElectronicsUnit

Panel

7-16 November 2000


COMBINER DISPLAY

The graphic shows an exampledisplay during approach.

The horizon line shows an artificialhorizon. When the horizon line andairplane reference symbol overlap,the airplane is in a level, zero degreepitch attitude.

Airplane reference shows theprojected centerline of the airplane.The function of this symbol isequivalent in operation to theairplane symbol on a standard EADI.

Airspeed shows on the left side of thecombiner.

Barometric altitude shows on theright side of the combiner.

A pitch scale shows above andbelow the horizon line.

The roll scale and pointer are abovethe airplane reference symbol. Thescale shows bank angle.

The flight path symbol shows theflight path vector of the airplane. Thissymbol gives an instant indication ofwhere the airplane is going. The pilotcan operate the airplane and fly aflight path to a desired point.

The guidance cue functions thesame way as an integrated cue flightdirector. For the pilot, the objective isto capture the guidance cue insidethe flight path symbol circle with pitchand roll control inputs.

Selected speed shows the airspeedthe pilot sets on the DFCS modecontrol panel (MCP). It also showsthe airspeed command set by theFMCS.

Selected altitude shows the altitudeset on the MCP.

Combiner Display

Selected Speed

Airspeed Scale and Index

Flight PathGuidance Cue

Selected Altitude

Altitude Scaleand IndexHorizon Line

Airplane ReferencePitch Scale

Roll Scale and Pointer

Autoflight

November 2000 8-1

• Flight Management ComputerSystem (FMCS)

• Dual Flight ManagementComputers

• Digital Flight Control System(DFCS)

• Autothrottle

• Built-In Test Equipment (BITE)

• Wheel to Rudder InterconnectSystem (WTRIS)

Features

FLIGHT MANAGEMENTCOMPUTER SYSTEM (FMCS)

The FMCS allows preplanned flightprofile control and guidance for bestperformance and performancemanagement.

OPTIONAL DUAL FLIGHTMANAGEMENT COMPUTERSYSTEM

A dual system permits navigationunder the primary means ofnavigation criteria.

DIGITAL FLIGHT CONTROLSYSTEM (DFCS)

The DFCS includes these functions:

• Autopilot• Flight director• Mach trim• Speed trim• Altitude alert.

AUTOTHROTTLE

The autothrottle controls the enginesindependently to get the bestperformance.

BUILT-IN TEST EQUIPMENT (BITE)

The BITE system gives fast andaccurate troubleshooting of the mainflight management system (FMS)components.

YAW DAMPER/WHEEL TORUDDER INTERCONNECTSYSTEM (WRTIS)

The yaw damper decreases the yawrates associated with dutch roll andturbulence. The WTRIS assistsmanual turns when both A and Bhydraulic systems are in standby.

8-2 November 2000

Flight Management System (FMS)

The flight management system is agroup of systems that operatetogether to decrease flight crewworkload. The design of the systempermits fast, accurate trouble-shooting and maintenance. You dothe built-in test (BITE) for most of theFMS components from a commonlocation. The BITE procedures foreach system are almost the same.

FLIGHT MANAGEMENTCOMPUTER SYSTEM (FMCS)

The central part of the flightmanagement system is the flightmanagement computer system(FMCS).

The flight crew uses the controldisplay unit (CDU) to enter the routeand performance data for the flight.The FMC calculates the lateral andvertical components of the flight. Itthen sends commands to the other

systems of the FMS to follow theflight plan. The BITE for other FMSsystems goes through the FMC andshows on the CDU.

DIGITAL FLIGHT CONTROLSYSTEM (DFCS)

The digital flight control system(DFCS) includes the autopilot, flightdirector, and other functions. For afully automatic flight, the FMCcommands the autopilot to fly theroute.

AUTOTHROTTLE (A/T) SYSTEM

The autothrottle (A/T) systemcontrols the engine thrust levers. TheFMC sends thrust and speed targetsto the autothrottle for best overallflight performance.

AIR DATA INERTIAL REFERENCESYSTEM (ADIRS)

The air data/inertial referencesystem (ADIRS) supplies attitude, airdata, and navigation information tothe other FMS systems.

COMMON DISPLAY SYSTEM(CDS)

FMS information shows on thecommon display system (CDS).

YAW DAMPER/WTRIS FUNCTION

The yaw damper and WTRISfunctions are part of the stallmanagement yaw damper (SMYD).

The yaw damper gives commands tothe rudder to decrease yaw ratesfrom dutch roll and turbulence. TheWTRIS assists manual turns whenon the standby hydraulic system.The BITE for the SMYD is on thefront of the SMYD.

Flight Management System

FMCS A/T SystemDFCS CDS

Common Yaw Damper

SMYD

ModeControlPanel

FlightControlComputers

FlightManagement

ControlDisplayUnit

AutothrottleComputerComputer

ADIRS

DisplaySystem

WTRISFunctions

Air DataInertialReferenceUnits

Autoflight

November 2000 8-3

Flight Management ComputerSystem (FMCS)

The flight management computer(FMC) is the main component of theflight management computer system.The flight crew uses the controldisplay unit (CDU) to schedule theroute and performance for the flight.With this flight plan data and inputsfrom airplane sensors, the FMC doesthese operations:

• Navigation• Performance• Guidance.

An optional connection to the aircraftcommunication and reporting system(ACARS) is available. It lets the FMCreceive flight plan data from a groundstation and send flight status to theground station.

NAVIGATION

A navigation data base stored in theFMC memory includes the

navigation data for the area ofoperation. You update the data baseevery 28 days. The pilot canpreselect the entire flight plan fromthe navigation data base withstandard air traffic control language.Also, the flight crew can have theFMC fly an offset from the route.Required time of arrival (RTA) is alsoavailable.

The FMC calculates the airplaneposition as the flight continues. Ituses the inertial reference functionand navigation aids, if available, tocalculate the position. The FMCcompares the calculated positionwith the planned position. Anydeviation shows on the commondisplay system.

PERFORMANCE

A performance data base in the FMCcontains a performance model of theairplane and the engines. The flightcrew enters gross weight, cruise

altitude, and cost index for the flight.The FMC uses this data to calculatethe economy speeds, best flightaltitude, and top of descent point.The CDU and the flight displaysshow target speeds and altitudes.

GUIDANCE

The FMC sends commands to thedigital flight control system (DFCS)and the autothrottle (A/T). The DFCSand the A/T use these signals tocontrol the airplane in the lateral(LNAV) and vertical (VNAV) parts ofthe flight plan.

BUILT-IN TEST EQUIPMENT (BITE)

The maintenance technician usesthe CDU to operate BITE for theFMC. The full self tests of the FMCand the ability to see the status of theinputs and outputs permits fasttrouble-shooting.

Flight Management Computer System

Waypoint

AlterationCourse

Waypoint

OuterMarker

DescentTop Of

GuidanceTakeoff And Altitudes

Optimized Speeds

DestinationApproach

ILS

Waypoint

Cruise

ClimbTop Of

ClimbStep

Climb

Origin

Flight Control Computer (2)

Stall Management Yaw Damper (2)

DME Interrogator(2)

Display Electronic Unit (2)

Navigation Control Panel (2)

Autothrottle Computer

Flight Data Acquisition Unit

Ground Proximity Warning Computer

Control DisplayUnit (CDU) (2)

Flight ManagementComputer (FMC)

Aircraft Communication and Reporting System

PWRON

FMCVALID

CDS


8-4 November 2000

Dual Flight ManagementComputer (FMC)

The dual FMC configuration is a flightmanagement computer system(FMCS) option. It permits navigationunder the primary means ofnavigation criteria. This lets theairplane fly a more direct route whichsaves fuel and time. The maincomponents are two flightmanagement computers and twocontrol display units (CDUs).

Each FMC makes a positioncalculation with different sets ofnavigation aids and ADIRU inputs. Ifnavigation aids are not available, theFMCs only use separate ADIRUinputs for the calculation. The FMCscombine their calculations tocalculate a best position. Both FMCstransmit this best position to the CDSand other user systems.

One FMC is the primary FMC and theother is the secondary. A transferswitch controls the systemconfiguration through transfer relays.When the transfer switch is inNORMAL or BOTH ON LEFT, FMC 1is primary and FMC 2 is secondary.When the transfer switch is in BOTHON RIGHT, FMC 2 is primary andFMC 1 is secondary.

When the transfer switch is inNORMAL, FMC 1 sends data to allsingle systems and to the number 1system of dual systems. The datafrom FMC 2 goes to the number 2system of dual systems. When thetransfer switch is in BOTH ON LEFT,FMC 1 is the source for all outputs.When the transfer switch in BOTHON RIGHT, FMC 2 is the source forall outputs.

The output of each CDU connects toboth FMCs. The primary FMCprocesses the CDU inputs and sendsthe data to the secondary FMC. Thedisplay on both of the CDUs is fromthe primary FMC.

The two FMCs compare inputs andoutputs at all times. A largedifference between the two causesthe secondary FMC to conditionallyfail and to alert the flight crew.

Dual FMC Option

ON L ON R

NORMAL

FMC

BOTH BOTH

A/PP/RST

FMCP/RST

A/TP/RST

TEST

1

2

Normal/BothOn L

OutputsDigital

P5

Autoflight Status

FMC 1

FMC 2

CDU 1

CDU 2

BothOn R

Relaysand

TransferSwitch

ON VALIDPWR FMC

ON VALIDPWR FMC

Annunciator (2)

Autoflight

November 2000 8-5

Digital Flight Control System(DFCS)

Two independent flight controlcomputers (FCCs) control thesefunctions:

• Autopilot• Flight director• Altitude alert• Mach trim• Speed trim.

To do these functions, each FCCdoes these things:

• Receives flight crew requestsand airplane sensor inputs

• Does the calculations for eachfunction

• Controls the indicators andactuators for each function.

AUTOPILOT/FLIGHT DIRECTOR

The flight crew uses the modecontrol panel to control the autopilotand the flight director. The crew

engages the autopilot, turns on theflight director, selects the modes,and selects the targets on the MCP.For the autopilot function, the FCCsends commands to the autopilotaileron and elevator actuators tocontrol the surfaces. For the flightdirector function, the FCC sendspitch and roll guidance commands tothe common display system. Thestatus and the mode of operation ofthe autopilot and the flight directorshow on the common displaysystem.

MACH TRIM AND SPEED TRIM

Mach trim and speed trim functionsoperate with no flight crew input.

For mach trim, the FCC controls themach trim actuator. It moves theelevator to increase airplane stabilityat high air speeds.

For speed trim, the FCC controls thestabilizer trim electric actuator. It

moves the stabilizer to increaseairplane stability at low air speeds.

ALTITUDE ALERT

The altitude alert function uses thealtitude selected on the mode controlpanel. The FCC alerts the flight crewwhen the airplane approaches ordeparts the selected altitude. Thereis an aural alert from the remoteelectronics unit and a visual alert onthe common display system.

DISENGAGE WARNING

There is a visual and an auralwarning to alert the flight crew if theautopilot disengages. A red light onthe autoflight status annunciator andthe wailer from the aural warningmodule give the warning.

BITE

The flight control computer givesaccurate, reliable, and fast built-intest (BITE) capability.

Digital Flight Control System

Flight Control

ModuleWarningAural

ToneAlertAltitude

UnitElectronicRemote

Sensors

Mach Trim Actuator

Electric ActuatorStabilizer Trim

Elevator ActuatorsAutopilot Aileron and


Computer (2)

Autoflight StatusAnnunciator (2)

A/PP/RST

FMCP/RST

A/TP/RST

TEST

1

2

Mode Control Panel (P7)

COURSE

F/D

OFF

N1 SPEED

OFF

ARMA/T

C/O

IAS/MACH

LVL CHG HDG SEL APP

VOR LOC

L NAVHEADINGV NAV ALTITUDE

SEL

ALT HLD V/S

UP

DN

VERT SPEEDA/P ENGAGE

CMD A CMD B

CWS BCWS A

MA

F/DDISENGAGE

OFF

COURSE

MA

8-6 November 2000

Autothrottle

The full-range autothrottle systemcan control the thrust levers fromtakeoff to touchdown. It givesmaximum fuel conservation throughsmooth, precise thrust control. Likeother flight managementsubsystems, the autothrottle designgives maximum operational and costbenefits.

There is a single autothrottle com-puter that operates the thrust leversthrough two independentservomotors. The autothrottlecontrols the engines independentlyto get the best performance fromeach engines. These are the autothrottle controls in the flightcompartment:

• Arm switch on the mode controlpanel (MCP) arms theautothrottle

• Takeoff/go-around (TO/GA)switches select the takeoff or

go-around modes• Autothrottle (A/T) disconnect

switches disconnect theautothrottle

• Mode select push-buttons on theMCP select thrust or speedcontrol.

The flight crew can select theautothrottle mode with the modeselect push-buttons on the MCP.Usually the digital flight controlsystem selects the correctautothrottle mode for the flightphase. The active autothrottle modeshows on the common displaysystem.

The autothrottle moves the thrustlevers to control thrust or airspeed.For thrust control, the FMCcalculates the correct thrust settingfor the flight phase. For airspeedcontrol, the autothrottle acceptsmach and airspeed commands fromthe FMC or MCP. The autothrottleoperates with the electronic engine

control to give improvedperformance.

A red light on the autoflight statusannunciator gives a visual warning ifthe autothrottle disengages.

The autothrottle system has built-intest. This lets you do fast accuratemaintenance. You do the tests of theautothrottle system with the CDU.From the CDU, you can select thesefunctions:

• Current status• Inflight faults• Interactive• Ident/Config.

Autothrottle System

N1 SPEED

OFF

ARMA/T

C/O

IAS/MACH

Computer (2)Flight Control

Flight

ComputerAutothrottle

Sensor

Thrust ModeAnnunciator

Engine (2)

Mode ControlPanel (P7)

EICAS Display

AutothrottleServomotor (2)

TO/GA Switches


A/PP/RST

FMCP/RST

A/TP/RST

TEST

1

2

A/T DisconnectSwitches

ManagementComputer

Annunciator (2)Autoflight Status

Autoflight

November 2000 8-7

Autoflight Modes And ModeDisplay

Mode selection and system engageswitches for the autopilot, flightdirector, and autothrottle are on themode control panel (MCP).

The TO/GA switches select takeoffand go-around modes. They are onthe thrust levers. The engage statusand mode of operation show on thedisplay units.

The takeoff mode is a combinedflight director and autothrottle mode.The autothrottle sets engine thrust tothe target value calculated by theflight management computer (FMC).The flight director gives commandsto control the rate of climb and thento control the selected airspeed seton the MCP.

Vertical navigation (VNAV) andlateral navigation (LNAV) are thenormal cruise modes. When thesemodes are selected, the FMC sendscommands to the autopilot, flightdirector, and autothrottle. Theairplane flies the FMC route at theairspeed and altitude for the selectedperformance. The autopilot, flightdirector, and autothrottle worktogether in these modes.

Other modes are available at theoption of the crew. The crew canselect modes to change and hold theairplane altitude and to fly a radiobeam or heading. The crew uses themode control panel to select thedesired autopilot and flight directormode. The autopilot or flight directorthen sets the autothrottle mode thatgives the best combinedperformance.

The approach mode (APP) is forlanding. In the approach mode, theflight director and the autopilot uselocalizer and glideslope radiosignals. When the approach mode isselected, you can engage bothautopilots for an automatic landing.The autothrottle holds the MCPselected airspeed in approach.

In go-around, the autothrottle setsthe thrust levers to go-around thrust.The flight director and, if available,the autopilot, control rate of climb,airspeed, and track.

The flight mode annunciator (FMA) ison the primary flight display.Autopilot flight director status showsin the status field of the FMA.Autothrottle, pitch, and roll modesshow in the other positions of theFMA.

Autoflight

TO/GA Switches

StatusAutothrottle Autopilot/Flight

Mode Control Panel (P7)

Primary Flight Display

COURSE

F/D

OFF

N1 SPEED

OFF

ARMA/T

C/O

IAS/MACH

LVL CHG HDG SEL APP

VOR LOC

L NAVHEADINGV NAV ALTITUDE

SEL

ALT HLD V/S

UP

DN

VERT SPEEDA/P ENGAGE

CMD A CMD B

CWS BCWS A

MA

F/DDISENGAGE

OFF

COURSE

MA

Mode Director Modes

8-8 November 2000

Built-In Test Equipment (BITE)

The CDU gives access to self-contained in-flight monitoring andground test capabilities for thesesystems or components:

• Flight management computersystem - FMCS

• Digital flight control system -DFCS

• Autothrottle - A/T• Air data inertial reference system

- ADIRS• Common display system - CDS• Electronic engine control -

ENGINES• Electronic control unit - APU• Fuel quantity indicating system -

FQIS.

Each FMS component contains testsfor itself, its sensor inputs, and otherinterfaces. Also, each componentstores in-flight fault data for analysison the ground.

A technician uses the CDU to controlthese BITE functions. All systemBITE displays are on the CDU inEnglish.

The technician selects test optionsfrom a menu and supplies interactiveoperator responses through theCDU. BITE does the tests andsupplies data to the technician to dotrouble-shooting. The technicianuses the verification tests to do a testof the interfaces after replacement ofa line replaceable unit (LRU).

The system allows fast, linemaintenance fault isolation to asingle line replaceable unit. Fast andaccurate diagnostics mean fewerdelays and smaller sparesinventories.

The ENGINES prompt gives accessto engine exceedance data forpresent and past flights. The APUprompt gives access to APU faultand system information. The FQISprompt gives access to fuel quantitysystem fault and system information.

Built-In Test Equipment

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Autoflight

November 2000 8-9

Yaw Damper/WTRIS

The yaw damper moves the rudderto decrease yaw rates that arerelated to dutch roll. The WTRISassists manual turns when thestandby hydraulic system is on.

The yaw damper system connects tothe main and standby rudder powercontrol units to do the yaw damperfunction. SMYD 1 connects to themain rudder power control unit.SMYD 2 connects to the standbyrudder power control unit. TheWTRIS function is only in SMYD 2.

These are the yaw dampercomponents in the flightcompartment:

• Yaw damper switch• Yaw damper warn light• Yaw damper indicator.

The yaw damper is available for thefull flight. You engage the yawdamper and the WTRIS with the yawdamper switch on the overheadpanel. The yaw damper warn lightgoes off when the yaw damper isengaged.

The yaw damper uses inputs fromthe inertial reference function of theADIRU to get airplane yaw rate andlateral acceleration. The yawdampers send commands to therudder power control units to movethe rudder and stop the dutch roll.The rudder pedals do not move whenthe yaw damper moves the rudder.The yaw damper indicator showsyaw damper movement of therudder.

The WTRIS senses control wheelmovement and sends commands tothe standby rudder power control unitto move the rudder.

Monitor circuitry in the computerdisengages the yaw damper/WTRISfor problems with the positionfeedback or with the servo.

You do a test of the yaw damper andWTRIS functions at the stallmanagement yaw damper. A menulets you select these BITE functions:

• Existing faults• Fault history• Ground tests• Other functions.

Yaw Damper/WTRIS System

Yaw Damper Indicator

Rudder Power

ADIRU

Command

Feedback

Control Units

Stall Management

Control WheelPosition Sensor

ON

OFF

aDAMPER

YAW

YAW DAMPER

XXXXXXXXXX

XXXXXXXXXX

XXXXXXXXXXXX

X X

X

Yaw Damper (2)

YAW DAMPER

Warning Light and EngageSwitch (P5 Flight ControlPanel)

(P2 Center Instrument Panel)

Electrical Power

November 2000 9-1

• Electrical Power System

• Power Control and Protection

• Controls and Indications

• Control, Indication, and BITE

• System Power Distribution, DCStandby Power Control

• Electrical Component Location

Features

THREE ELECTRICALGENERATORS

Two generators are engine-drivenand one is APU-driven.

AUXILIARY POWER UNIT (APU)

The APU makes the airplane self-sufficient. It supplies electrical poweron the ground and in flight.

AUTOMATIC BUS TRANSFERSYSTEM

This system increases electricalpower reliability and reduces pilotworkload.

ACCESSIBLE ELECTRONICEQUIPMENT RACKS

You have access to all electronicracks from the ground.

BATTERY FOR STANDBY DC ANDAC STANDBY POWER

The airplane battery supplies powerto the standby system when normalpower fails. The battery suppliespower to essential systems for aminimum of thirty minutes.

BUILT-IN TEST ANDTROUBLESHOOTING

Operational information shows in theflight compartment. Built-in testfeatures are in the protection andcontrol units in the electronicequipment (EE) compartment and onthe P5 panel in the flightcompartment.

9-2 November 2000

Electrical Power System

The electrical power system supplies115v ac and 28v dc electrical powerto the airplane.

AC Power Distribution

The electrical power distributionsystem normally operates as twoseparate systems. IDG 1 supplies acpower to transfer bus 1. IDG 2supplies ac power to transfer bus 2.

The APU can supply power to bothtransfer buses on the ground and inflight.

AC power sources include thesecomponents:

• Two IDG units, each driven by anengine, supply115v ac. Each IDGsupplies up to 90 KVA

• A starter-generator is a 90 KVA(to 32000 ft, 66 KVA above)generator and an electric starter

for the APU• External power receptacle rated

at 90 KVA.

External power supplies the airplanein these two ways.

• From the external powerreceptacle directly to the groundservice buses. The groundservice buses supply cabinlighting, electrical outlets, and thebattery chargers

• From the external powerreceptacle through the externalpower contactor (EPC) and bustie breakers (BTBs), whichsupply power to all buses.

Bus Transfer System

If either transfer bus loses power, thebus power control unit (BPCU) usesengine generator control units(GCUs) to close the bus tie breakers(BTB) to supply power from theopposite transfer bus. BPCU

controlled load shed relays shedloads as necessary in this condition.Bus transfer allows continuation ofnormal flight operations. The pilotstarts and uses the APU. The BTBsopen when the bus has power again.

Bus Protection

There are four AC system controlunits; three GCUs and the BPCU.The BPCU provides overall systemmanagement and protection. Inaddition to a GCU, the APU has astart converter unit (SCU) forexcitation and voltage regulation.The engine GCUs supply generatorvoltage regulation and protection.

There is protection for these faults:

• Differential current• Over/under voltage• Over/under frequency• Overcurrent• Unbalanced phase current.

Rectifier 2Transformer

Electrical Power Distribution

GCB1

External Pwr AC

GCB2

Battery ChargerBattery

115V AC GndService Bus 2

Standby Bus 1115V AC

Standby Bus28V DC Static

Inverter

Hot Battery Bus28V DC Switched

Battery Bus28V DC Hot28V DC Bus 1


28V DC Bus 2Battery Bus28V DC


Main Bus 1115V AC Galley

BTB2BTB1

EPC

BPCU

APB

115V AC GndService Bus 1

GCU

115V AC Transfer Bus 1

AGCU

SCU

Main Bus 2115V AC Galley

GCU

115V AC Transfer Bus 2

GENGEN APU

Aux

Aux

Battery

BatteryCharger

Electrical Power

November 2000 9-3

DC Power Distribution

The 28v dc system has thesecomponents:

• Three transformer rectifiers(TRs). The TRs convert 115v acto 28v dc

• One 36 ampere-hour (AH)battery or optional, two 40 AH or48 AH batteries

• Battery charger(s).

DC BUSES

The main battery or the main batterycharger supplies power to the hotbattery bus and the switched hotbattery bus. Whichever has thehigher output voltage becomes thesource.

TR 3 normally energizes the batterybus. Transfer bus 2 or transfer bus 1energizes TR 3. If TR 3 fails, thebattery charger or the batterysupplies power to the battery bus.

TR 1 and TR 2 and alternately TR 3normally supply power to dc buses 1and 2. DC bus 1 is the normal sourcefor the dc standby bus. The batterybus alternately supplies the dcstandby bus.

Standby Power

The auxiliary battery and/or the mainbattery are the standby source ofpower. The standby system suppliesac and dc power to primary flightinstruments, communication,navigation, and other equipment. Ifall ac generators fail, ac transfer bus1 does not have power. Thiscondition results in these functions:

• The batteries energize the dcstandby bus

• The static inverter energizes theac standby bus. The inverteruses battery power to createsingle phase 115v ac.

Automatic control of the standby anddc system is in the standby powercontrol unit (SPCU). The SPCU is inthe P6 panel in the flightcompartment. The SPCU controlsthe contactors in the system andmonitors the status of the buses andrelays. The SPCU also suppliesinformation to the flightcompartment.

Ground Power

The APU generator is a convenientpower source for ground operation.In addition, external 115v ac powerconnects through a receptacle on theright side above the nose gearwheelwell. A switch on the forwardoverhead panel connects this powerto the airplane system. Anotherswitch on the forward attendantpanel connects this power to cabinrelated service circuits and thebattery charger.

Power Control and Protection

Bus Power Control Unit Generator Control Unit

FAULT

FAULT

BPCU

BUS FAULT

EPC

EP DIST/

TEST

BPCU

PASS

BPCU

FAULTBTB

FAULT

FAULT

FAULT

FAULT

GCUFAULT

FEEDER

PASSGCU

GCB/APB

IDG

TEST

GCU

DIST/BUS

9-4 November 2000

Controls and Indications

These electrical power controls andindications are on the P5 forwardoverhead panel.

The DC AMPS meter shows thecurrent of TR1, TR2, TR 3, and BAT.The selector controls the indication.

The DC VOLTS meter shows thevoltage of the source selected by thedc meter selector (all positions).

The DC meter selector selects the dcsource for the dc voltmeter andammeter indications. The TESTposition connects the dc meters to aBITE in the panel.

The BAT switch switches the hotbattery bus. The switched hot batterybus connects to the battery with theswitch on and guard down. Thebattery is then available for backup tothe ac and dc standby buses.

The CPS FREQ meter shows thefrequency of the source selected bythe AC meter selector.

The AC VOLTS meter shows thevoltage of the source selected.

The AC AMPS meter shows loadcurrent (phase B) of the generatorsource selected by the ac meterselector.

The AC meter selector selects the acsource for ac volt and frequencyindications. The TEST positionconnects the AC meters to a BITE inthe panel.

The GALLEY switch supplieselectrical power to the galleys.

BITE

The ELEC light shows that there is aBITE message. This is the procedureto see a BITE message:

• Airplane on ground• Put the AC and DC meter

selectors to TEST• Push the MAINT button.

Messages show on the display.These are examples of BITEmessages:

• BAT CHGR INOP• AUX BAT CHGR INOP• SPCU INOP• PANEL FAILURE• INTERFACE FAILURE• STAT INV INOP• TR3 XFR RLY INOP.

The amber TR UNIT light comes onwhen any of the TR units fail on theground. It also comes on when TRU1or TRU2 and TRU3 fail in the air.

The amber BAT DISCHARGE lightcomes on when a large current flowoccurs in a short time.

ELEC

Control, Indication, and BITE


a a a

BAT

DC VOLTS / AC AMPS / AC VOLTS

DC AMP CPS FREQ

DISCHARGE TR UNIT

AC

BAT GALLEY

DC

BAT

TEST

BATBUS

OFF

ON

OFF

ON

GRDPWR

GEN1

APU GEN

GEN2

MAINT

INV

PWRSTBY

PWRSTBY

TR1

TR2

TR3

AUX BAT

TEST

Electrical Power

June 1998 9-5

Controls and Indications

The STANDBY PWR OFF lightcomes on amber when the standbyac or dc bus does not havepower.The light also comes on whenthe battery bus does not have powerand the battery switch is in the onposition.

The STANDBY PWR switch hasthese three positions:

• AUTO - Normal position. Thebattery or batteries automaticallyconnect to supply the dc standbyand ac standby buses with loss ofall ac power in flight

• OFF - Turns off power to thestandby power buses

• BAT - The battery or batteriessupply power to the battery bus,dc standby bus, and ac standbybus.

The amber DRIVE light comes onwhen IDG 1 or IDG 2 oil pressure islow.

The DISCONNECT switchdeenergizes IDG 1 or 2 anddisconnects the input shaft. Theengine start levers must be in the idleposition for the disconnect tooperate.

The GRD POWER AVAILABLE lightcomes on blue when ground power isconnected to the receptacle. Thequality of the ground power mustalso be good for the light to come on.

The TRANSFER BUS OFF lightscome on amber when a transfer busdoes not get power by any source.

The SOURCE OFF light comes onamber when a transfer bus does notget power by the selected engine,APU generator, or external power.

The GEN OFF BUS light comes onblue when the IDG does not supplypower to the transfer bus on thesame side.

The APU GEN OFF BUS light comeson blue when the APU is in operationbut the generator does not supplypower to one or both transfer buses.

The GEN1, APU GEN, and GEN2switches are three-position switches,momentary on/off and spring loadedto center.

The BUS TRANSFER switch hasthese two positions:

• AUTO (guard down) - Transferbus automatically transfers toopposite power source if normalsource is inoperative

• OFF - Isolates left and right sidesand prevents bus transfer.

Control and Indication


9-6 November 2000

Aircraft Installation

Two power distribution panels(PDPs) in the EE compartment andtwo circuit breaker panels in the flightcompartment contain the electricalpower buses. The main buses andindividual high power load controlsare in the two PDPs. Lower currentbuses and individual load controlsare in the PDPs and the circuitbreaker panels in the flightcompartment.

Electronic Equipment Racks

Electronic and electrical equipmentare on racks in the EE compartmentbelow the cabin floor, aft of the nosegear wheel well. You can easily getaccess from the ground through theaccess door in the lower body.

Wiring

Wire bundles have numbers for quickidentification to wiring diagrams anddrawings. They are in raceways thatrun the length of the airplane. Theraceways minimize radiointerference, reduce wire splicing,and permit wire bundle removal andreplacement.

Automatic Load Shedding

Several methods protect theelectrical system from damage.These are the methods:

• The BPCU sheds noncriticalloads when there is a loss of anac power supply

• Failure of components andassociated wiring disconnectfrom the bus by circuit breakers

• The GCU trips the generatorbreaker when there is a left orright system problem

• Automatic electrical isolation ofleft and right sides when landing.

System Power Distribution, DC Standby Power Control

WINDOWHEAT

POWER

CDS

FUEL SYSTEM

AC/DCBUS IND

AIR

FMCS

P6-3

P6-1

P6-2

COND

PRESS

P6-4

P6-11P6-12

P6-5

WXR

MASTER CAUTIONLANDING GEARENGINE FUEL

APU

EQUIPCOOLING

RADIO NAV B

ELEC

AC/DCPOWERRECP

RADIO NAV 1AUTO FLT A

AUTO THROTTLE

P18-3

P18-4

P18-2

P18-1

EQUIP COOLING

INTERIOR/EXTERIORANTI-ICE & RAIN

ACCOMPASS

COMM 1

FLT RECORDER

CDSENGINE 1

EN

G 2

FLT

CO

NT

INP

H P

WR

FIR

EP

RO

T

AU

TOF

LT B

HY

D S

YS

Flight Compartment P6, P18(Looking Aft)

STANDBYPOWER

CONTROLUNIT

LIGHTING

OXYGENLAVATORIES

SMYD 1

L ADIRU

COMM 2

R ADIRU

SMYD 2

First ObserverSeat (Stowed)

Second ObserverSeat (Optional)

WINDOWHEAT

POWER

Electrical Power

June 1998 9-7

EE Compartment ElectricalEquipment

ELECTRICAL SYSTEM BITE

The GCUs collect and showmaintenance data from the GCU,GCB, IDG, and power feeders. Afront panel display on each GCUshows any failures.

The BPCU collects and showsmaintenance data from the BPCU,EPC, and ground power feeders. Afront panel display on the BPCUshows failures.

The APU start converter unit (SCU)collects maintenance data from thestart power unit (SPU) and voltageregulator (VR). Fault data goes to theAPU electronic control unit (ECU).This information and other APU datagoes to the control display units(CDUs) in the flight compartment.

COMPONENT LOCATION

The E2 equipment rack has thesecomponents:

• APU SCU• AGCU• GCU 1• TRU 1• Main battery charger• Static inverter.

Power distribution panel 1 (PDP 1),P91, below the E2 rack, has thesecomponents in it:

• BTB 1• GCB 1• AGB 1• Transfer bus 1• Main bus 1.

The J9 junction box has thesecomponents in it:

• Static inverter RCCB• Auxiliary battery RCCB.

The E3 equipment rack has theauxiliary battery charger. Theauxiliary battery, and/or the mainbattery are below the E3 equipmentrack.

The E4 equipment rack has thesecomponents:

• BPCU• GCU 2• TRU 2• TRU 3.

Power distribution panel 2 (PDP 2),P92, below the E4 rack, has thesecomponents in it:

• BTB 2• GCB 2• EPC• Transfer bus 2• Main bus 2.

Electrical Component Location

GCU 2TRU 3 TRU 2

TRU 1

GCU 1AGCU

J9 Junction Box

Batteries

EE Access Door

StaticInverter

Auxiliary BatteryCharger

APU StartConverterUnit

Bus PowerControl Unit

E2, E3, E4 Equipment Racks

PDP 2(P92)

PDP 1(P91)

Main BatteryCharger

Fuel

November 2000 10-1

• Fuel Tanks and Vent System

• Pressure Refuel System

• Defuel System

• Engine and APU Fuel FeedSystem

• Fuel and Water ScavengeSystem

• Fuel Quantity IndicatingSystem

• Fuel System Control

Features

FUEL CAPACITY

Each of the two main tanks holds8,630 pounds (3,915 kg) of fuel. Thecenter tank holds 28,803 pounds(13,066 kg) of fuel.

UNDERWING REFUEL STATION

The refuel station is in the right wing.The maximum refuel rate is 2025pounds (918 kg) per minute. Themaximum refuel pressure is 55 psi.

FUEL TANK COMPONENTREPLACEMENT WITHOUTDEFUELING

Defueling is not necessary forremoval of many fuel systemcomponents that are on the front andrear spar.

AUTOMATIC WATER SCAVENGESYSTEM

An automatic water scavengesystem decreases wateraccumulation in the center and maintanks.

AUTOMATIC CENTER TANKSCAVENGE

The automatic center tank scavengesystem transfers residual center tankfuel to main tank 1. This increasesthe quantity of usable fuel.

FUEL QUANTITY INDICATINGSYSTEM (FQIS)

The FQIS uses a variablecapacitance principle and anadvanced microprocessor tomeasure fuel quantity.

JETTISON SYSTEM NOTNECESSARY

Because the maximum take offweight is not substantially higherthan the maximum landing weight, afuel jettison system is not necessary.

10-2 November 2000

Fuel Tanks

The fuel system has these fuel tanks:

• Main tank 1• Main tank 2• Center tank.

There is a surge tank at the outer endof main tank 1 and 2. The surgetanks are part of the wing structure.

Most fuel system components areinside the tanks. The boost pumpsand scavenge pumps are on the frontand the rear spar. You can removethese components without defueling.

Fuel Vent System

The fuel vent system keeps the fueltanks at near ambient pressureduring all phases of airplaneoperation. Each tank vents to thesurge tanks through channels in thewing.

The vent channels also permit fueloverflow into the surge tank ifnecessary.

Fuel Tanks and Vent System

Surge Tank

Main Tank 21,288 US Gal(4,876 Liters)

Main Tank 11,288 US Gal(4,876 Liters)

Center Tank4,299 US Gal(16,273 Liters)

Total Volume =6,875 US Gallons(26,025 Liters)

Surge Tank

Note:

8,630 Lbs(3,915 Kgs)

8,630 Lbs(3,915 Kgs)

28,803 Lbs(13,066 Kgs)

46,063 Lbs(20,896 Kgs)

Fuel

November 2000 10-3

Pressure Refuel System

The refuel station is on the right wing.It has a single refuel receptacle.

The refuel station has thesecomponents:

• Single refuel receptacle• Individual fuel quantity indicators• Fueling valve control switches• Fueling valve open lights• Fueling power control switch.

There is one fueling valve for eachtank. The fueling valve controlswitches on the refuel panel controlthe fueling valves. A fueling floatswitch in each tank closes the fuelingvalves when the fuel quantity in eachtank is at capacity. The fueling valvesalso operate manually.

Fueling can occur for each tankindividually or for all tanks at thesame time.

Power for the refuel system comesfrom the battery bus, the hot batterybus, and external power through thebus power control unit (BPCU)transformer rectifier.

Pressure Refuel System

P15 Refuel Panel

Main Tank 1

Center Tank

Main Tank 2

Refuel Manifold

RefuelManifold

Refuel Manifold

Float Switch(3)

SWITCHBYPASS

FUELDOOR

GAUGESTEST

TANK 2 CENTER TANK TANK 1

FUEL QTYFUEL QTY FUEL QTY

OFF

OPEN

CLOSED

VALVE POSITION LIGHTS

OPEN

CLOSED

OPEN

CLOSED

LB LB LB

10-4 November 2000

Defuel System

The defuel system permits theremoval of fuel from each tank. It alsopermits the transfer of fuel betweentanks on the ground.

Use the fuel boost pumps to get fuelout of the tanks and into the fuel feedmanifold. When the defuel valve isopen, fuel transfers to the refuelstation.

The defuel valve operates manually.It is on the right front spar near therefuel station.

Use these components to transferfuel between tanks:

• Boost pumps• Defuel valve• Fueling valves.

A bypass valve in main tank 1 andmain tank 2 permits suction defuelingfrom those tanks.

Defuel System

Center Tank Boost Pumps

Forward Boost Pump Tank 1 Forward Boost Pump Tank 2

Refuel

Defuel Valve

Fuel Spar Valve Fuel Spar Valve

Bypass Valve Bypass Valve

Station

Aft Boost Pump Tank 1 Aft Boost Pump Tank 2

Crossfeed Valve

Fuel

November 2000 10-5

Engine Fuel Feed System

There are two boost pumps each formain tank 1, main tank 2, and thecenter tank. The boost pumps supplyfuel from the fuel tanks to theengines.

A crossfeed valve connects the leftand right fuel feed manifold. This letsany tank supply fuel to any enginewith the use of the applicable boostpumps.

The center tank boost pumps have ahigher output pressure than theboost pumps in the main tanks.Because of this, the engines receivecenter tank fuel first. With onlyresidual fuel in the center tank, theboost pumps in the main tankssupply fuel to the engines.

APU Fuel Feed System

The APU can receive fuel from anytank with the use of the applicableboost pump and crossfeed valve.

When the boost pumps are off, theAPU gets fuel from main tank 1.

An APU fuel shutoff valve lets fuelflow from the engine fuel feedmanifold to the APU fuel manifold.The APU master switch, on theforward overhead panel, controls theAPU fuel shutoff valve.

An optional APU DC fuel pumpsupplies fuel from main tank 1.

Engine and APU Fuel Feed System

Center Tank Boost Pumps

Forward Boost Pump Tank 1 Forward Boost Pump Tank 2

Refuel

Defuel Valve

Fuel Spar Valve

Bypass Valve

Station

Aft Boost Pump Tank 1

Aft Boost Pump Tank 2

Crossfeed Valve

To Engine

APU Fuel Shutoff Valve

To APUBypass Valve

Fuel Spar Valve

To Engine

10-6 November 2000

Fuel Scavenge System

The fuel scavenge system removesremaining fuel in the center tank andtransfers it to main tank 1. Thisincreases the usable fuel quantity inthe center tank.

The forward boost pump in main tank1 supplies motive flow to a jet pump.The jet pump removes fuel from thecenter tank and transfers it to maintank 1. A float valve controls fuel sentto main tank 1.

Water Scavenge System

The water scavenge systemremoves water from the low points ineach tank to help prevent corrosion.

There is a jet pump in the main tanks.There are two jet pumps in the centertank. The jet pumps in the main tanksuse motive flow from the aft boostpumps. The jet pumps in the centertank use motive flow from bothcenter tank boost pumps.

Each jet pump removes fuel andwater from its related tank anddischarges it to the boost pump inlet.The water mixes with the fuel andvaporizes during combustion.

Fuel and Water Scavenge System

Motive FlowDischarge

Motive FlowInlet

Fuel Scavenge System

Water Scavenge System

Boost Pump Inlet

Motive Flow Discharge

Motive Flow Inlet

Motive Flow Pump

Forward Boost PumpTank 1

Motive Flow Inlet

Float Valve

MotiveFlow Pump

Aft BoostPump (2)Boost Pump

InletMotiveFlow Pump

Center TankBoost Pump (2)

Fuel

November 2000 10-7

Fuel Quantity Indicating System

The fuel quantity indicating system(FQIS) measures fuel quantity,calculates fuel weight, and showsfuel weight. FQIS componentsinclude these components:

• Tank units• Compensators• Fuel quantity processor unit• Densitometer (optional).

The tank units supply a capacitancesignal that is equal to fuel depth. Thissignal goes to the FQIS processor.The processor uses the ARINC 429data bus to send a fuel weight signalto the common display system(CDS), the refuel panel, and the flightmanagement computer system(FMCS). There are 32 variablecapacitance tank units in the threetanks.

The compensators supply acapacitance signal that is equal tofuel quality and fuel temperature.This signal goes to the processor tocalculate fuel density. There is onecompensator in each tank.

The fuel quantity processor unit doesthese functions:

• Calculates total fuel weight• Calculates fuel weight in each

tank• Monitors the fuel system for faults• Sends fault data to the control

display units.

The fuel quantity processor alsosends fuel weight information to thecommon display system and the P15refuel panel. Fuel weight can show ineither pounds or kilograms.

An optional densitometer supplies asignal that is equal to fuel density.There is one densitometer in eachtank.

Fuel measuring sticks in each fueltank supply a direct indication of fuelquantity. The measuring stick is acalibrated, flat, bendable stick that isattached to the bottom surface of thewing.

The fuel quantity indicators on thedisplay units (DUs) in the flightcompartment can show thesemessages:

• LOW - when fuel quantity in amain tank is less than 2000lbs(907 kg)

• IMBAL - when the fuel quantitybetween the two main tanks isdifferent by more than 1000lbs(453 kg)

• CONFIG - when there is morethan 1600 lbs (725 kg) in thecenter tank, both center tankboost pumps are off, and eitheror both engines are on.

Fuel Quantity Indicating System

To Flight ManagementComputer System

Tank Unit (32)

Compensator (3)

Fuel Measuring Sticks (16)

Upper Display Unit

429 Data Bus

C

1

R

PUMPSFUEL

FUEL PUMPS

CROSS FEED

FWDAFT FWD AFT

2

L

CTR

50081

CTR

FUEL LB

2800050082

Fuel Control Panel (P5)

FuelTemperatureSensor

FQIS

P15 Refuel Panel

LOW

CONFIG

IMBAL

SWITCHBYPASS

FUELDOOR

GAUGESTEST

TANK 2 CENTER TANK TANK 1

FUEL QTYFUEL QTY FUEL QTY

OFF

OPEN

CLOSED

VALVE POSITION LIGHTS

OPEN

CLOSED

OPEN

CLOSED

LB LB LB

10-8 November 2000

Fuel System Control

The fuel system control is from theforward overhead panel.

Forward and aft fuel pump switchescontrol boost pump operation in maintank 1 and main tank 2. Amber LOWPRESSURE lights come on whenthe output pressure of the boostpump is low.

Center tank fuel pump switchescontrol boost pump operation in thecenter tank. LOW PRESSURE lightscome on when the output pressure ofthe pump is low and the fuel pumpswitch is ON.

A crossfeed selector controlscrossfeed valve operation. The blueVALVE OPEN light comes onbrightly when the valve is in transit.The VALVE OPEN light comes ondimly when the valve is open. TheVALVE OPEN light is off when the

crossfeed valve is closed and theselector is in the OFF position.

The blue SPAR VALVE CLOSEDlight comes on bright when the valveis in transit. The SPAR VALVECLOSED light is on dim when thevalve is closed. The SPAR VALVECLOSED light is off when the valve isclosed and the fuel pump switch isOFF.

The amber FILTER BYPASS lightscome on when the filter is going toclog. The fuel filter is on the enginefuel pump housing.

The fuel temperature indicator showsthe fuel temperature in main tank 1.

Fuel System Control

Fuel Control Panel


PRESSURELOW

PRESSURELOW

BYPASSFILTERVALVE

OPENBYPASSFILTER

aa

a

b

a

aaaa

b

b

b

b

LOWPRESSURE PRESSURE

LOWPRESSURE

LOWPRESSURE

LOW

CLOSEDCLOSED

SPAR VALVE SPAR VALVECLOSED CLOSED

ENG VALVE ENG VALVE

0FUELTEMP

C

-20 20

-40 40

OFF

ONON

ON

OFF

OFF

1

R

PUMPSFUEL

FUEL PUMPS

CROSS FEED

FWDAFT FWD AFT

2

L

CTR

Auxiliary Power Unit

November 2000 11-1

• Auxiliary Power System

• APU Fuel System

• APU Pneumatic System

• APU Lubrication System

• APU Ignition and StartingSystem

• APU Control and Indication

• APU BITE and MaintenanceIndications

Features

OPERATES ON THE GROUNDAND IN FLIGHT

The auxiliary power unit (APU) is anelectrical and pneumatic powersource for aircraft systems on theground and in flight.

ELECTRICAL POWER

A 90 KVA starter generator supplieselectrical power up to 32,000 feetaltitude. Above 32,000 feet to 41,000feet, the generator rating decreasesto approximately 66 KVA.

PNUEMATIC POWER

The load compressor suppliespneumatic power up to 17,000 feet.

APU STARTING

A starter-generator can start the APUat altitudes up to 41,000 feet.

EDUCTOR COOLING SYSTEM

An eductor cooling system cools theAPU compartment and the APU oil. Itis highly reliable and its parts do notmove.

OPERABLE DURING REFUELING

The APU can supply electrical andpneumatic power during refueling.

FULL AUTHORITY DIGITALELECTRONIC CONTROL

The electronic control unit (ECU) is afull authority, digital electronic controlunit that controls APU operation.

ENHANCED HISTORICALRECORDING

A data memory module records andkeeps APU operational data.

11-2 November 2000

Auxiliary Power System

The auxiliary power unit (APU)supplies electrical and pneumaticpower to the airplane. The APU canstart at all altitudes up to 41,000 feet.Electrical power is available up to41,000 feet. Pneumatic power isavailable up to 17,000 feet.

The APU is an AlliedSignal 131-9(B).The APU has these features:

• Single-stage centrifugalcompressor

• Two-stage axial turbine• Separate single-stage

centrifugal load compressor• Modular design.

The APU is in the aft section of thefuselage.

ELECTRONIC CONTROL UNIT

The electronic control unit (ECU)controls and monitors all phases ofAPU operation. It also stores systemand fault information. System andfault information shows on thecaptain and first officer controldisplay units (CDUs).

The ECU also causes an APUprotective shut down to preventdamage to the APU.

The ECU is in the aft cargocompartment, on the right side aft ofthe cargo door.

DATA MEMORY MODULE

A data memory module (DMM)records APU hours and starts. TheDMM also keeps various APUcomponent part and serial numbers.Programmed and recordedinformation shows on the captainand first officer CDUs.

The DMM is on the left side of theAPU compressor inlet plenum.

Auxiliary Power System

Electronic Control Data Memory ModuleUnit


November 2000 11-3

CompressorInlet Plenum

Starter/Generator

Oil Cooler

Bleed Control Valve

Oil Fill Port

Fuel Control Unit

Fuel Manifold

APU - Right Side

Accessory Gearbox

APU Components

Oil Cooler

Data Memory Module

Oil Fill Port

Starter/Generator

Igniter

Compressor Inlet Plenum

Fuel Control UnitLubrication Module

APU - Left Side

Oil Cooler TemperatureControl Valve

Accessory Gearbox

11-4 November 2000

APU Engine - Introduction

PURPOSE

The APU engine supplies power tooperate the load compressor and theAPU starter-generator.

GENERAL DESCRIPTION

The APU engine has these mainsections:

• Accessory gearbox• Single-stage load compressor• Single-stage engine compressor• Combustor chamber• Two-stage axial flow turbine.

All the components in the engine thatturn are on a common shaft.

The shaft turns the accessorygearbox and the load compressor.The accessory gearbox turns theAPU generator and othercomponents.

The engine operates at a constantspeed to provide 400 Hz generatoroutput. The APU engine alsosupplies air for airplane systems.

An inlet screen prevents foreignobject damage (FOD) to the APUcompressors.

APU Engine - Introduction

EngineCompressor Turbine Exhaust

GearboxLoadCompressor Air Inlet Combustor

SCV AirExit Duct

FWD


November 2000 11-5

APU Fuel System

The APU fuel system receives fuelfrom any fuel tank. The APU fuelsystem has these majorcomponents:

• Fuel control unit• Fuel flow divider• Primary and secondary fuel

manifolds.

FUEL CONTROL UNIT

The fuel control unit pressurizes,filters, and meters fuel. Theelectronic control unit sends fuelcontrol signals to the fuel control unit.The fuel control unit uses thesesignals to meter fuel. The electroniccontrol unit controls fuel flow fromstart to shutdown.

FUEL FLOW DIVIDER

The flow divider separates meteredfuel to the primary and secondaryfuel manifolds. The primary fuelmanifold always supplies fuel whenthe APU is in operation. The flowdivider supplies fuel to the secondarymanifold when metered fuel flowpressures increases to a certainlevel. The ECU controls a solenoidon the flow divider to change thesecondary manifold fuel supply withreference to altitude and APU speed.

The primary and secondary fuelmanifolds supply fuel to the fuelinjector nozzles.

INTERFACE

Regulated fuel pressure, from thefuel control unit, operates the inletguide vanes and the surge controlvalve actuator.

APU Fuel System

Fuel Manifold

Fuel Control Unit

APU

Fuel Feed

Fuel Flow Divider

Electronic ControlUnit

11-6 November 2000

APU Pneumatic System

The APU supplies pneumatic powerfor the environmental control systemand for main engine start.

The air inlet door directs air into theinlet plenum. The APU takes inletplenum air for use in two APUsections.

The APU has two separatecompressors, a power compressorand a load compressor. The powercompressor supplies compressed airto the combustor. The loadcompressor supplies compressed airto the airplane pneumatic system.The engine section operates the loadcompressor.

Inlet guide vanes control the amountof air that enters the loadcompressor. The ECU controls theinlet guide vanes with the inlet guidevane actuator. The inlet guide vaneactuator uses fuel pressure tooperate the inlet guide vanes.

A surge control valve lets enough airgo through to the load compressor toprevent a compressor surge. Thesurge control valve sends excesspressurized air to the APU exhaust.This protects the load compressorfrom a surge. The ECU controls thesurge control valve. Regulated servofuel pressure, from the fuel controlunit, operates the surge control valveactuator.

The ECU senses the APU bleedswitch position on the P5 panel in theflight deck. When the bleed switch isin the ON position, the ECUenergizes a solenoid on the bleed airvalve. When the solenoid energizes,APU bleed air duct pressure causesthe bleed air valve to move from theclosed to the open position.

The ECU monitors the position ofthese components:

• Inlet guide vane actuator• Surge control valve actuator• Bleed air valve.

The position of these componentscan be seen in the APU maintenancepages on the control display unit(CDU).

APU Pneumatic System

Surge

Inlet Guide

Load Compressor

Surge

Electronic Control

Transducer

Total PressureTransducer

Inlet Plenum

Delta P

FWD

Unit

Bleed Air

FWD

Bleed Air

Vane Actuator

Control Valve

Valve

ValveControl Valve


November 2000 11-7

APU Lubrication System

The lubrication system lubricatesand cools the gears, bearings, andshafts of these major components:

• Power compressor• Load compressor• Gearbox.

The lubrication system alsolubricates the APU starter-generator.

The lubrication module pressurizes,filters, and scavenges the oil. Thelubrication module contains thesecomponents:

• Pressure and scavenge pumps• Pressure and scavenge filters• High oil temperature sensor.

These are other lubrication systemcomponents:

• Low oil pressure switch• Starter-generator scavenge oil

filter differential pressure switch• Oil cooler• Temperature control valve• Magnetic chip detector• Air/oil separator.

The gearbox sump is the oilreservoir. An oil fill port supplies oil tothe reservoir. A sight glass shows oilquantity.

The gearbox vents to the APUexhaust.

From the reservoir, the oil ispressurized, filtered, and cooledbefore it goes to the majorcomponents and the starter-generator.

Scavenge pumps send oil to thescavenge filter before the oil returnsto the reservoir.

The APU exhaust gas operates aneductor. The eductor pulls APUcompartment air through the oilcooler to cool the oil and APUcompartment. A temperature controlvalve regulates oil flow to and fromthe oil cooler.

If the starter-generator scavenge oilfilter clogs, the differential pressureswitch operates. If the airplane is onthe ground and the engines are shutdown at the time of the clog, the ECUcauses an APU protective shutdown.

APU Lubrication System

CoolerOil

Oil Fill Port and Sight GlassLubrication Assembly

LubeModule

Magnetic ChipDetector/Drain Plug

TurbineBearingCompt

Starter-Generator

Scavenge

Pressure

CompressorLoad

CompressorEngine

Gearbox

Legend:

Oil Cooler

TemperatureControl Valve

Air/Oil Separator

Vent

Oil Level Sight Gageand Oil Level Sensor

TemperatureControlValve

DifferentialPressureSwitch

11-8 November 2000

APU Ignition and Start System

The ignition and start systemsupplies the combustion spark andstarts the APU acceleration. Thesystem includes these components:

• Starter-generator• Start power unit• Start converter unit• Ignition unit• Igniter.

The APU generator is also the APUstarter.

The start power unit (SPU) changesAC and low voltage DC to highvoltage DC power. The SPU thensends this high voltage DC power tothe start converter unit (SCU).

The start converter unit receives thehigh voltage DC electricity andchanges it to AC. The SCU thenmatches phases and sends the ACpower to the starter-generator. TheSCU increases the frequency of the

AC power supply to increase thespeed of the starter motor.

The starter-generator uses ACpower from the start converter unit toturn the APU gearbox and APU.

The ignition unit supplies electricalpower to the igniter unit. The ignitersupplies spark to the combustionchamber. The ECU controls thepower to the ignition unit.

APU Ignition and Start System

Start Converter Unit

APU

FAULT

OFF

ON

START

0

8

6

4 2

EGT

c x 100

10

MAINT

APU Start Switch

Start Power Unit

LOW OILPRESSURE

OVERSPEEDb a a a

and Indicators

Ignition Unitand Igniter Plug

ElectronicControl Unit

Starter-Generator


November 2000 11-9

Airborne Auxiliary Power -Operation - Start

GENERAL

You can start the APU up to analtitude of 41,000 feet (12,500meters).

The APU electronic control unit(ECU) controls these components:

• APU inlet door• APU fuel shutoff valve• APU fuel• Ignition• APU start system.

PRESTART

The battery switch must be ONbefore you can start and operate theAPU. If AC power is available,operate one or more of the fuel boostpumps. This gives pressurized fuel tothe APU. Pressurized fuel makes theAPU start better.

APU START

Move the APU switch to the STARTposition and release it. This sends asignal to the electronic control unit(ECU). The ECU then opens theAPU fuel shutoff valve and the APUair inlet door. The ECU also causesthe low oil pressure light to come on.When the air inlet door is fully open,the door switch sends a door fullyopen signal to the ECU.

APU SEQUENCE

The ECU controls this APU startsequence:

• At 0 percent speed and beforethe start system is energized, theECU energizes the ignition unit

• At 0 percent speed for start or 7percent speed for restart, theECU energizes the starter-generator

• At 7 percent speed, the fuelsolenoid valve opens

• At approximately 30 percentspeed, the low oil pressure light(P5) goes out.

• At 60 percent speed, the ignitionunit deenergizes

• At 70 percent speed, the starter-generator deenergizes

• At 95 percent speed, the APUcan supply electrical power andair

• The APU accelerates to, andstays at 100 percent speed.

Note: The inlet guide vanes (IGVs)close to 15 degrees with the APUbleed air valve closed. This keepsthe load compressor cool when itdoes not have a load.

The BAT DISCHARGE light on theelectrical meters, battery, and galleypower module comes on when theAPU start uses DC power. The BATDISCHARGE light does not come onwhen the APU uses AC power tostart.

APU Engine - Operation - Start

100% 100% Governed Speed

Electric and PneumaticLoads are Available

Starter-Generator Deenergizes

Ignition Unit Deenergizes

Fuel Solenoid Valve Opens

APU

FAULTb a a

OFF

ON

START

0

8

6

4 2

EGT

oc x 100

10

MAINTa

LOW OILPRESSURE

OVERSPEED

APU Switch (P5)

• Battery Switch On

60 Seconds (Std Day)When you put the APU switch to ON

Low Oil Pressure Light (P5) Goes Out

• Ignition Unit Energizes

• APU Switch to the START

95%

70%

60%

30%

7%

• APU Fuel Shutoff Valve Open

• Air Inlet Door Open

• Starter-Generator Energizes

or START, the APU fuel shutoff valveand air inlet door opens.

Position & Release to ON

1

1

11-10 November 2000

APU Control and Indication

CONTROL

The ECU controls these APUfunctions:

• Start and ignition• Fuel control• Surge control• Inlet guide vane control• Normal shutdown• Protective shutdown• APU indications• BITE/fault recording• Data storage.

The APU switch on the P5 panelcontrols normal APU start andshutdown.

INDICATION

The indicator on the P5 panel showsexhaust gas temperature.

The MAINT light comes on whenthere is an APU maintenanceproblem. Maintenance problems donot always require immediate action.

The LOW OIL PRESSURE lightcomes on when the APU oil pressureis low. Low oil pressure causes aprotective shutdown.

The FAULT light comes on when theAPU has a fault that causes aprotective shutdown.

The OVERSPEED light comes onwhen the APU speed is too high anda protective shutdown occurs. Thelight also comes on when theoverspeed protection test fails andoverspeed protection is lost.

APU Control and Indication


APU Switch and APU Indicators

10

OVERSPEEDFAULTMAINT

APU

OFF

START

ON

0 C X 100

EGT8

6

4 2

a aabPRESSURE

LOW OIL


November 2000 11-11

Airborne Auxiliary Power -Protective Shutdown

GENERAL

A protective shutdown preventsdamage to the APU or the airplane.

The ECU controls the automaticprotective shutdown of the APU.If the ECU finds a fault, it does aprotective shutdown.

There are three different protectiveshutdown indications in the flightdeck. These are the flightcompartment protective shutdownindications:

• Fault light• Overspeed light• Low oil pressure light.

The cause for the shutdown showson the control display unit (CDU) onthe P9 panel.

PROTECTIVE SHUTDOWN

These are the conditions that causea protective shutdown and a faultlight:

• Fuel shutoff valve not incommanded position

• Loss of dc power• ECU failure• APU fire• Inlet door not in commanded

position• APU inlet overheat• Loss of both EGT signals• No speed signal• No acceleration• No APU rotation• No flame (no ignition)• Generator filter clogged• High oil temperature• Overtemperature (EGT)• Reverse flow (load compressor)• Oil temperature or inlet air

temperature sensor failure• Underspeed.

These are the conditions that causea protective shutdown and anoverspeed light:

• Fuel control unit solenoid failure• Loss of overspeed protection• Overspeed.

Low oil pressure for 20 secondscauses a protective shutdown and alow oil pressure light.

When a protective shutdown occurs,the ECU removes electrical powerfrom these components:

• Fuel solenoid• Ignitor• SCU start signal• Bleed air valve (BAV)• Fuel control unit (FCU)• Surge control valve (SCV).

APU - Protective Shutdown

- FIRE SHUTDOWN

- APU FUEL VALVE SHUTDOWN

- ECU SHUTDOWN

- FUEL CONTROL UNIT SOLENOID FAILURE

- OIL TEMPERATURE SHUTDOWN

- INLET DOOR SHUTDOWN

- DC POWERLOSS SHUTDOWN

- LOSS OF EGT SHUTDOWN

- OVERSPEED PROTECTION

- OIL PRESSURE SHUTDOWN

- NO ACCELERATION SHUTDOWN

- NO FLAME SHUTDOWN

- LOSS OF SPEED SHUTDOWN

- OVERSPEED SHUTDOWN

- OVERTEMPERATURE SHUTDOWN - REVERSE FLOW SHUTDOWN

- UNDERSPEED SHUTDOWN

- INLET OVERHEAT SHUTDOWN

ECU

CDU Display (P9)

PROTECTIVE SHUTDOWN CONDITIONS

- OIL FILTER SHUTDOWN

FAULT LIGHT

OVERSPEED LIGHT

LOW OIL PRESSURE LIGHT

FAULT

0

8

64 2

EGT

ocx100

10

MAINTLOW OIL

PRESSUREOVER

SPEED

APU Indicator Panel (P5)

>

<

<

<

<

<

>

1/1 - SENSOR FAILURE

- NO APU ROTATION SHUTDOWN

APU BITE TESTMAIN MENU

CURRENT STATUS

FAULT HISTORY

MAINTENANCE HISTORY

IDENT / CONFIG

INPUT MONITORING

INDEX OIL QUANTITY

11-12 November 2000

APU BITE and MaintenanceIndications

The ECU sends real time andrecorded fault information to thecaptain and first officer controldisplay unit (CDU).

APU BITE and Maintenance Indications

NT STATUS

MAIN MENU

GIFNC

GNIROTIT NOMUPNI

OIL

>

FAUL T HI STORY

IDENT / O

<

<

<

<

CURRE<

I DEXN

APU BITE TEST

>YTITNAUQ

MAINTENANCE HISTORY

1/1

BITE Test Main Menu

SEE FAULT ISOLATION

MANUAL

MAINT MESS# 49 - X X X XX

SHUT DOWNACCELERATIONNO

61 /

11031

CYCLES OLDGMTATED

AULT HISTORYF

>< I DEXN C TNERRU S SAT TU

Fault History Display

/

A

A

DISP

ISP

ISP

C

AM

P4 9 HP29315.028.31605 .2.60.09

1.08

C056

%0.001

NOITISOP

NOITISOP

LEUF

LEUF

SSERP

SSERP

SSERP

TELNI

TELNI

WOLF

CMT

PMET

LATOT

ATLED

VCS

VGI

TGE

DEEPS

41SRETEMARAPEMITLAER

TSETETIBUPA

N XEDI<

GED

GED

BITE REAL TIME DISPLAY

CYCLE

CONFIRM REPAIR

ECU OTOTPOWER

QUANTITYOILLOW

CURRENT STATUS

APU BITE TEST

<

/1 3

Current Status Display

< I DEXN

PU B ITE TESTA61 /

103140TCO

DLOSELCYCTMGETAD

YROTSIH

M A I N T M E S S # 4 9 - X X X XX

0

M A I N T E N A N C E

B L E E D A I R P O S I T I O N

D I S A G R E E S HTW I

V A L V E

S SUTAT >

O M M A N DC

Maintenance History

A TSETETIBUP

N XEDI<

/1 2I D E N T / H O U R S / O I L

A P U S / N

C Y C L E S

1 0 1

1 1 6 5

H O U R SA P U

A P U

8 3 6

O L E V E L F U L LLI

Ident/Config Display Input Monitoring Display

APU BITE TEST

MAINT MESS# 49 - X X X XX

( LATCHED )

INDEX

OCT 04

CURRENT

Power Plant

November 2000 12-1

• CFM56-7B Engines

• Engine Buildup

• Engine Installation

• Engine Control System

• Fuel System

• Oil System

• Air System

• Common Display System(CDS)

• Engine Start System

• BITE

• Reverse Thrust

Features

THRUST

The CFM56-7B high bypass turbofanengine produces 18,500 to 27,300pounds of thrust.

HIGH RELIABILITY

High reliability is built into this engine.The CFM56-7 engine is a derivativeof and has years of on-wingexperience from the CFM56-3 andCFM56-5 engines.

MAINTENANCE

Engine mechanics benefit from the737 eye-level maintenance design.The cowls move easily outward andsupply access for maintenance. Thisgives quick access to meet short turnaround times.

Engine buildup is identical for left andright engines. Engine change iseasier with these features:

• On wing hoist attachments• Step-by-step manual• Improved access.

QUIET CABIN

A quiet cabin is made possible bythese features:

• An advanced broadbandacoustical liner

• No inlet guide vanes• Fully lined fan duct• Shroudless wide-chord fan

blades• High-bypass-ratio design.

COMMON DISPLAY SYSTEM

New liquid crystal display units (DUs)supply flight and maintenance crewswith highly reliable and easy-to-readindications and messages.

BUILT-IN TEST EQUIPMENT

Engine component and exceedancedata are easy to access. The controldisplay unit (CDU) shows theelectronic engine control (EEC) built-in test equipment (BITE).

NEW TECHNOLOGY

An electronic engine control for eachengine increases fuel efficiency andengine response. New wide-chordfan blades provide theseadvantages:

• Higher thrust• Improved aerodynamics• Improved strength• Improved bird-strike protection• Less vibration.

12-2 November 2000

CFM56-7 Engines

The 737 airplane uses two CFM56-7high bypass-ratio turbofan enginesthat attach to the wing. The engineshave several thrust ratings. Theengine is an axial flow turbofan withtwo spools.

The engine has a low and highpressure section. The low pressuresection has these features:

• A single-stage fan• A three-stage low pressure

compressor• Titanium wide-chord fan blades• Four-stage low pressure turbine.

The high pressure section has thesefeatures:

• Nin- stage high pressurecompressor

• Single-stage high pressureturbine.

The engine core uses a provendesign with improvements based onnew technology and customer input.

The main gearbox supplies power foraircraft and engine accessories. Themain gearbox attaches to the side ofthe fan case. The high pressuresection drives the gearbox.

Engine Installation

There are improvements which makeengine removal and installationeasier. Fan cowl panels are hingedto the strut. They are quicklyremoved to give ground level accessto the engine. The thrust reversercowls also have hinges to the strutthat stay with the airplane. Theengine attaches to the strut with eighttension bolts and two thrust links.Electrical, pneumatic, and hydraulicsystems quickly connect anddisconnect.

Engine Buildup

These components are on theengine:

• Starter• Integrated drive generator (IDG)• Hydraulic pump• Cowling• Thrust reverser• Fire/overheat detectors• Common display and CDU data

links• Pneumatic ducts and valves• Engine mounts and thrust links• Nozzle/plug• Inlet.

The buildup for both engines is thesame except for the vortex controldevice (VCD) on the fan cowl, andthrust reversers.

CFM56-7 Engine Characteristics Summary

CFM56-7B18 CFM56-7B24CFM56-7B20 CFM56-7B22 CFM56-7B26

Airplane Rating

Airplane

18,500

-600 -600/700

20,000 22,000

-700

24,000

-700/800

26,000

-800

CFM56-7B27

27,000

-800/900

Bypass Ratio 5.6 5.5 5.4 5.3 5.1 5.0

Thrust, lb

Power Plant

November 2000 12-3

Fuel Pump

Hydromechanical Unit

Fuel Flow Transmitter

Wide ChordFan Blades

Accessory Gearbox

EEC Alternator

Starter

Integrated Drive Generator

Hydraulic Pump

Fuel Nozzles

Low Pressure Turbine

In-line Fuel Filter

Active ClearanceControl

Transfer Gearbox

Left Side

Integrated Drive Generator (ref)

CFM56-7 Engine

PrecoolerControl Valve

Inlet TAI Valveand Duct

Electronic Engine

Oil Tank

LPTACC Duct

HPTACC Duct

Ignition Exciters

Right Spark Igniter

Fuel Nozzles

LPTACC Valve

HPTACC Valve

Electronic EngineControl Cooling

Right Side

Control

Forward EngineMount

Aft EngineMount

12-4 November 2000

Engine - General Description

GENERAL

The CFM56-7 is a high bypass, dualrotor, axial flow turbofan engine. Theengine fan diameter is 61 inches(1.55 meters). The bare engineweight is 5257 pounds (2385kilograms).

The engine has these sections:

• Fan and booster or low pressurecompressor (LPC)

• High pressure compressor (HCP)• Combustor• High pressure turbine• Low pressure turbine (LPT)• Accessory drive.

The fan and booster rotor and theLPC rotor are on the same lowpressure shaft (N1).

The HPC rotor and the HPT rotor areon the same high pressure shaft(N2).

FAN AND BOOSTER (N1)

The fan and booster is a four-stagecompressor. A splitter fairing dividesthe air into primary and secondary airflows. The primary air flow goes intothe core of the engine. The boosterincreases the pressure of this air andsends it to the HPC. The secondaryair flow goes in the fan duct. Itsupplies approximately 80 percent ofthe thrust during take-off.

HIGH PRESSURE COMPRESSOR(N2)

The HPC is a nine-stagecompressor. It increases thepressure of the air from the LPC andsends it to the combustor. The HPCalso supplies bleed air for thepneumatic system and the engine airsystem.

COMBUSTOR

The combustor mixes air from thecompressors and fuel from the fuel

nozzles. This mixture of air and fuelburns in the combustion chamber tomake hot gases. The hot gases go tothe HPT.

HIGH PRESSURE TURBINE (HPT)

The HPT is a single-stage turbine. Itchanges the energy of the hot gasesinto a mechanical energy. The HPTturns the HPC rotor and theaccessory drive.

LOW PRESSURE TURBINE (LPT)

The LPT is a four-stage turbine. Itchanges the energy of the hot gasesinto a mechanical energy. The LPTturns the fan and booster rotor.

ACCESSORY DRIVE

The engine HPC shaft drives theaccessory gearbox (AGB). The AGBholds and operates the airplaneaccessories and the engineaccessories.

General Description

N1 Shaft

N2 Shaft

Inlet Gearbox

Radial

Transfer

Horizontal

Accessory

Secondary Air Flow

Primary Air Flow

High PressureCompressor

Combustor High PressureTurbine

Low PressureTurbine

Fan and Booster

Fuel

FanDuct

DriveShaft

Nozzles(20)

Gearbox

Drive Shaft

Gearbox

Splitter Fairing

Power Plant

November 2000 12-5

Engine Control System

The electronic engine control (EEC)controls these engine functions:

• Thrust management• Engine systems• Engine fault detection, storage,

and recall• Engine communication with other

airplane systems.

The EEC is a two-channel, digitalelectronic device. Each channel isfunctionally divided. If one channel isunable to maintain a control function;the EEC uses that part of the otherchannel to supply the control.

The EEC has normal and alternatemodes of operation. If air dataparameters become unavailable, theEEC goes to a soft alternate mode.When the flight crew moves thethrust lever to idle, the EEC goes tohard alternate mode. You push aswitch on the aft P5 overhead panel

to put the EEC in the hard alternatemode before dispatch.

The engine-driven EEC alternatorsupplies power to the EEC. Theairplane electrical system suppliesalternate power to the EEC.

Engine sensors supply engine statusinformation to the EEC. Thesesensors and airplane control inputsdetermine EEC response.

The EEC controls and monitors thehydromechanical unit (HMU). TheHMU uses fuel with pressure (servo)to control compressor airflow.Control of compressor airflow is bythese devices:

• Variable stator vanes (VSVs)• Variable bleed valves (VBVs)• Transient bleed valve (TBV).

High pressure and low pressureturbine active clearance control(HPTACC, LPTACC) supply variableamounts of cool air to the hot turbinesections of the engine. The HMUuses servo fuel to control HPTACCand LPTACC.

The HMU uses servo fuel to controlfuel flow to the nozzles and theburner staging valve (BSV). The BSVsupplies fuel to additional fuelnozzles for higher engine speeds.

The EEC also controls and monitorsthe thrust reversers, starting, andignition.

Engine Control System

737-6/7/800

VSV

VBV

HPTACC

LPTACC

TBV

BSV

Fuel Nozzles

Start Lever

Alt Electric Power

Status ReportingMaint Reporting

Engine Reporting

Thrust ResolverBleed DataFlight Data

Auto Thrust DataStart/Ignition Data

UnitHydromechanical

Electronic Engine Control (EEC) IgnitionExciters

and ValveFeedback

ActuatorAlternatorEEC Engine

RPMEngineTemperatures

EnginePressures

FuelFlow(N1,N2)

Air FlowControl

ClearanceControl

FuelControl

Turbine

Fuel InServo

12-6 November 2000

Fuel System

The engine fuel system has thesefunctions:

• Supplies fuel to the engine forcombustion

• Cools the engine oil and IDG oil• Supplies servo fuel to the

hydromechanical unit (HMU) andengine system actuators andvalves.

Fuel tank boost pumps take fuel fromthe tanks and supply the engine. Thefuel goes through a shutoff valve inthe front spar. The fuel then goes tothe engine.

The main gearbox on the enginedrives a two-stage fuel pump. Thefuel pump supplies high pressurefuel to the HMU. The EEC controlsthe HMU fuel metering valve fromthrust lever position, engine systemstatus, and airplane operation. Themetered fuel goes to the combustion

chamber. Unused fuel goes back tothe fuel pump.

The engine start lever and engine fireswitch control the fuel shutoff valve inthe HMU. The engine start lever andfire switch also control the spar valvein the front spar of the wing. Whenthe engine fuel shutoff valve closes,the ENG VALVE CLOSED light onthe P5 forward overhead panelcomes on dim blue. When the sparvalve closes, the SPAR VALVECLOSED light comes on dim blue.

Fuel moves from the first stage of thefuel pump through two fuel/oil heatexchangers to a filter. Fuel canbypass the heat exchangers or thefilter if there is a failure or blockage.The amber FILTER BYPASS light onthe P5 panel comes on amber beforefuel bypass happens at the filter.

The second stage of the fuel pumpsupplies high pressure fuel to theHMU. As the fuel leaves the secondstage fuel pump, some of it goesthrough a servo wash filter. This fuelthen goes through a servo fuelheater before it goes to the HMU forservo operation. Most of the fuel notcleaned by the servo wash filter alsogoes to the HMU. This fuel becomesa metered supply for the combustionchamber.

A fuel flow transmitter measures therate of fuel flow from the HMU. Fuelflow shows on the CDS fuel flowindicator.

Engine Fuel and Oil System Schematic

IDG

Fuel Pump

PumpLow Press

ValveShutoffFuel

PumpsScavenge

BSV

Fuel Filter

ExchangerFuel HeatMain Oil/

HP Pump

Oil PumpOil FilterOil Qty

To Bearings/GearboxOil Return

Fuel FlowTransmitter

OilPress

OilTank

Fan Air

Oil Cooler

Bypass

Spar

FilterBypass 10 fuel

Nozzles

EEC

OilTemp

Filter

B

B

Spar ValveClosed

Eng

10 fuelNozzles

Fuel In

FuelFlow

StartLeverInput

VSV

VBV

TBV

HPTACC

LPTACC

Hydro-mechanicalUnit

Servo WashFilter

Servo FuelHeater

A

A

ValveClosed

Power Plant

November 2000 12-7

Oil System

The oil system lubricates and coolsthe engine.

Oil is kept in the engine oil tank. Theoil quantity in the oil tank shows onthe engine display.

The oil system gets pressure fromthe engine-driven supply oil pump.The system measures oil pressurejust after the pump. Oil pressureshows on the engine display. LOWOIL PRESS indication shows on theengine display. The indication is anamber message.

The oil goes through a supply oilfilter. If the filter clogs, oil bypassesthe filter. Oil filter bypass indicationshows on the bypass valve housing.The indication is a red pop-outindicator.

The three-element, engine-drivenscavenge pump sends the oilthrough a scavenge filter. If the filterclogs, the oil goes around the filter.Before the oil goes around the filter,an OIL FILTER BYP caution showson the engine display. The indicationis an amber message.

An oil temperature sensor is in the oilsupply line. Oil temperature showson the engine display.

Oil goes through the fuel/oil heatexchanger. This cools the oil before itgoes to the oil tank.

Oil circulates under pressure throughthe engine to lubricate the enginebearings, accessory gearbox, andtransfer gearbox.

The oil quantity shows as apercentage of quantity on the enginedisplay.

Fuel and Oil Indication

Fuel ValveP5 Forward

FILTERBY PASS

VALVEOPEN

FILTERBY PASS

CROSS FEED

FUEL PUMPS

FUEL

PUMPS

FWDAFT

OFF

RLON

CTRLOW

PRESSURELOW

PRESSURELOW

PRESSURELOW

PRESSURE

LOWPRESSURE

LOWPRESSURE

ON ON

AFTFWDOFFOFF

1 2

ENG VALVECLOSED

SPAR VALVECLOSED

ENG VALVECLOSED

SPAR VALVECLOSED

Fuel Panel

Fuel Filter

OverheadPanel

Engine Display

P2 CenterInstrumentPanel

Fuel Flow/Fuel Used

- Oil Filter Bypass Warning- Low Oil Pressure Warning- Oil Pressure- Oil Temperature

Closed Lights

Bypass Valve

12-8 November 2000

Air System

BLEED AIR

Bleed air supply comes from the highpressure compressor for thesesystems:

• Air conditioning• Cabin pressurization• Wing and engine inlet cowl anti-

ice.

Air comes from the fifth stage of thecompressor at high power settings.Air comes from ninth stage at lowpower settings.

Fan air cools the bleed air in theprecooler. Fan air also cools theintegrated drive generator (IDG).

TURBINE CLEARANCE CONTROL

High pressure turbine activeclearance control (HPTACC) usesfourth and ninth stage air to cool andcontrol expansion of the highpressure turbine shroud assembly.Fan air supplies the low pressureturbine active clearance control(LPTACC) to control low pressureturbine clearances. Fifth stage aircools turbine components.

COMPRESSOR AIRFLOWCONTROL SYSTEM

Compressor airflow control includesthese systems:

• Variable stator vanes (VSVs)• Transient bleed valve (TBV)• Variable bleed valves (VBVs).

The VSVs control the flow of air thatgoes through the high pressurecompressor.

The TBV releases 9th stage highpressure compressor (HPC) airduring start. This permits thecompressor to rotate easier. Thisvalve also releases HPC air duringtransient mode operation to helpmake the engine more stable.

The VBVs prevent low pressurecompressor stalls. Stalls may occurwhen the engine RPM changes. TheVBVs discharge booster air into thefan air flow to unload the lowpressure compressor. The VBVsalso control the amount of air thatgoes to the HPC, relative to enginespeed.

Air Bleed System

Fan Air

Fourth Stage Bleed Air

Ninth Stage Bleed Air- Air Conditioning and Wing Anti-ice- Inlet Cowl Anti-Ice

- HPTACC

- HPTACC

Fifth Stage Bleed Air- Inlet Cowl Anti-Ice

- IDG Oil Cooling- Bleed Air Precooler- LPTACC

- Air Conditioning and Wing Anti-Ice

- Low Pressure Turbine Nozzle Cooling

- Transient Bleed Valve Vent

Power Plant

November 2000 12-9

Common Display System (CDS)

Engine and hydraulic informationshow on a single liquid crystal display(LCD) engine display.

Primary and secondary engine dataand controls for the engine displayinclude these features:

• N1 shows the fan and lowpressure compressor (LPC)speed in percent RPM

• The N1 display becomes redwhen the LPC speed exceedsthe limits

• N2 shows the high pressurecompressor (HPC) speed inpercent RPM

• The N2 display becomes redwhen the HPC speed exceedsthe limits

• Exhaust gas temperature (EGT)shows in degrees C

• The box around EGT digitaldisplay flashes twice per secondif a hot start occurs. The sides of

the box also get thicker• The EGT display becomes red

when the start and maximumtemperature exceeds the limits.The display is amber whentemperature goes to themaximum takeoff power range

• A red box around each digitalindication stays on after engineshutdown.

• Fuel flow indication shows fuelflow in weight of fuel per hour andalso total fuel used per engine.

• The FUEL FLOW/FUEL USEDswitch changes the indicationfrom FUEL FLOW to FUELUSED. After 10 seconds, theFUEL USED display goes backto FUEL FLOW.

• The FUEL USED RESET switchresets the fuel used counter tozero

• Engine oil pressure in PSI• Engine oil temperature in

degrees C• The oil pressure and oil

temperature displays become

amber or red when there is anexceedance

• Engine oil quantity is a digitaldisplay that shows in percent offull. The display becomes reversevideo and a low message showswhen the quantity is low

• Engine vibration shows in scalarunits

• Hydraulic pressure shows inpounds per square inch (PSI)

• Hydraulic quantity showshydraulic system reservoirquantity in percent of full. Moreinformation about hydraulicsystem pressure and quantity isin the CDS and hydraulic systemchapters of this book.

FUEL FLOW

SPD REFN1 SET

SYSENG

MFD

AUTOBOTH

SET R

REFV

AUTO

RESET

1

2

RATE

USED

WT

V

V1

Engine Display

Engine Display

Engine Display Control Panel

P2 Center Instrument Panel

12-10 November 2000

Engine Start System

The engine start system uses airpressure and electric power forstarter operation. The engines canstart with air from any one of thesesources:

• APU• Ground source• Engine cross bleed.

The start lever for each engine is onthe control stand. In the IDLEposition, the start lever energizes theignition system and permits fuel flow.

The engine start switch in the GRDposition opens the start valve.Compressed air from the pneumaticmanifold turns the starter. When thestart valve is open, the START VLVOPEN message on the enginedisplay comes on amber. The starteris a turbine motor that turns the highpressure compressor through theaccessory drive-gear system. Whenthe engine accelerates to 25 percentN2 RPM and the engine start lever isin the IDLE position, these eventsoccur:

• Spar and engine fuel shutoffvalves open

• HMU supplies fuel to thecombustor

• Igniters energize• Start switch goes to OFF at 55%

N2 and ignition stops• Start valve closes and the START

VLV OPEN message goes out• Engine stabilizes at idle.

IGNITION

Each engine has two high energyignition systems. Both systems useac power. The ignition select switchlets the operator use either the LEFT,RIGHT or BOTH igniters for eachengine. The FLT position of theengine start switch bypasses theignition select switch and usesBOTH. You use the FLT position forrain and icing conditions. You usethe CONT position for takeoff,landing, and in turbulence. Thishelps to prevent flameout if a bird,ice, or water goes into the engineduring a critical flight phase.

Engine Controls

ENGINE START

Fuel

Bleed Air

From

SystemPneumatic

HMUStartValve

StarterAir-driven

GRDOFF CONT

FLTBOTH

IGNL

IGNR

Idle

Cutoff

Start Lever

DEU

Ignition Exciter (2)

Spark Igniter (2)

Thrust Lever

Engine Displays

EEC

EngData

FromFuelSystem

P5 ForwardEngine Start Panel

Legend:

Overhead Panel

Power Plant

November 2000 12-11

From APU

TAI - Thermal Anti-ice

RegulatorHP Bleed

9th

Stage5th

Stage

Cowl TAIInlet

Start Valve

Starter

ValveHigh Stage

9thStage

Stage5th

Cowl TAIInlet

Start Valve

Starter

Bleed AirIsolationValve

DuctPressureTransmitter

DuctPressureTransmitter

PneumaticGroundConnectionWing TAI

ValveWing TAIValve

PackValve

PackValve

ReliefValve

APUReliefValve

AccessoryGearbox

AccessoryGearbox

PressureRegulatorandShutoffValve

FanFan

Note:

PressureRegulatorandShutoffValve

Pneumatic Starting System

Engine Controls

Engine

Forward thrustLevers

Start Levers

Reverse ThrustLevers

Control Stand

12-12 November 2000

SYSTEM FAULTS AND BITE

CONTROL DISPLAY UNIT

The CDU shows exceedance datafor each engine. A red exceedancebox on the engine display tellsmaintenance personnel to get BITEdata from the CDU. BITE data showsthe most current exceedance eventand the flight leg. Historical datashows on other CDU pages.

In addition to exceedance data,engine fault data is available on theCDU. All fault messages have anumber that is in the fault isolationmanual (FIM). Past and present flightfault data may be recalled. The CDUalso supplies this data:

• Engine configuration• Functional test data on engine

control components and theignition system.

ENGINE PANEL

An ENGINE CONTROL Indicationlight comes on for a major enginefault. This light, on the aft P5 panel, isamber. The airplane must be on theground for the light to come on. Theengine may or may not be running.

Air data faults cause the ALTNamber light to come on. For airplanedispatch, both EEC switches are putto off. This makes both engines run inthe hard-alternate mode. Thisprocedure prevents unequal thrustand throttle stagger. The crew mustbe careful to not exceed the ratedengine thrust in this mode.

Fault Isolation

RTE

LEGS

FIX

PREVPAGE

N1LIMIT

DIRINTC

NEXTPAGE

HOLD

CRZ

DEPARR

CLB

PROG

DES

EXEC

BRT

A B C D E

F G H I J

K L M N O

P Q R S T

V W X Y

1

0

8 9

654

7

2 3

+/ -

LIAF

YPSD

a

w

U

Z DEL CLR/

TSFO

GSM

w

w

INITREF

UPA

XEDNI

SDC

T/A

S

SCFD

CMF

1/1NI DEXETIBTNAM I

<

<

<

<

>

>

<

< AD I RU

Engine Panel (P5)

Control Display Unit

ENGINE

>FQIS

aREVERSER

EEC

aCONTROLENGINE

aALTN

wON

1 ENGINE 2

aREVERSER

EEC

wON

aALTN

ENGINEaCONTROL

Power Plant

November 2000 12-13

Thrust Reversers

The thrust reversers (TRs) useelectrical control. The TRs operatewith hydraulic power. Both TRs areinterchangeable between the twoengines except for the cascades.

Reverse thrust occurs with a changeof fan air direction. When the thrustreversers deploy, the blocker doorsclose and fan air goes out radiallyand forward.

When the translating sleeves extend,these events occur:

• Cascades uncover• Blocker doors deploy• Blocked fan air goes out through

the cascades• Cascades direct the fan air

forward.

Thrust Reverser Operation

Deployed

Drag Link

(10)Blocker Door

Drag Link

Stowed

Reverse Thrust

Forward Thrust

(10)Blocker Door

Translating SleeveTranslating Sleeve Cascades

12-14 November 2000

Thrust Reverser Operation

The TR system may be armed onlyduring these conditions:

• Airplane on the ground or lessthan 10 feet from the ground

• The fire warning switches are inthe normal position.

DEPLOY

The TR system arms whenmovement of the reverse thrustlevers sends power to the controlvalve modules. This energizessolenoids which open valves. Thevalve modules are in the mainlanding gear wheel wells. The valvessend pressurized hydraulic fluid tothe TR actuators. The actuatorsmove the sleeves to the deployposition. When the sleeves deploy,the electronic engine controlreleases an interlock that permitsfurther movement of the reverse

thrust lever. This movementincreases reverse thrust power.

STOW

Movement of the reverse thrust leverto the stow position changes thedirection of hydraulic fluid. Theactuators move the sleeves to thestow position.

The TR hydraulic system pressurizeswhen you select reverse thrust. Italso pressurizes when the automaticrestow system energizes.

Each engine TR system gets powerfrom separate hydraulic systems.Hydraulic system A supplies powerto the left engine TR. System Bsupplies power to the right engineTR. The standby hydraulic systemsupplies power to the left, right, orboth engine TRs if loss of the normalhydraulic system pressure occurs.The standby system reduces the TRdeployment and stow rate.

An automatic restow systemactivates when the engine accessoryunit (EAU) senses a sleeve out of thestow position.

Thrust Reverser Actuation System Schematic

System A Hydraulics STBY Hydraulics

Stow Deploy

Deploy

Ground

Stow

Deploy

Stow

Fire WarningSwitch

Thrust Lever

AirControlValveModule

Reverser DeployedEngine 1

Interlock

Eng Accy

Actuator

Angle Resolver

Electronic EngineControl

Unit

28V DC

T/R Sleeve Position

Power Plant

November 2000 12-15

Thrust Reverser Indication

The EEC must be on to sense thrustreverser sleeve position. The EECsends a signal to the DEUs for thrustreverser sleeve position.

A REV indication shows above theN1 indication on the engine displaywhen the thrust reverser operates.The indication is amber if the thrustreverser is not in the commandedposition. The indication is greenwhen the thrust reverser is in the full-deploy position. The indicator is offwhen the reverser is in the stowposition.

The engine accessory unit (EAU)operates a REVERSER fault light.The lights are on the engine panel onthe P5 aft overhead panel. When thisfault light comes on, the mastercaution light also comes on after 15seconds delay. When the lightcomes on, do a test of the system.

BITE is on the EAU in the EEcompartment for fault isolation.

Thrust Reverser Indication

Engine Display

P2 CenterInstrumentPanel


aREVERSER

EEC

aCONTROLENGINE

aALTN

wON

1 ENGINE 2

aREVERSER

EEC

wON

aALTN

ENGINEaCONTROL

Engine Panel

Hydraulics

November 2000 13-1

• Hydraulic Systems

• System Distribution

• System Controls

• Servicing

• Maintenance

• Pressure Module

Features

TRIPLE REDUNDANCY

System A has one engine-drivenpump (EDP) and one electric motor-driven pump (EMDP) for thesesystems:

• Flight controls• Flight spoilers• Landing gear• Nose gear steering• Alternate brakes• Left thrust reverser• Ground spoilers.

System B has one engine-drivenpump and one electric motor-drivenpump for these systems:

• Flight controls• Flight spoilers• Normal brakes• Trailing edge flaps• Leading edge devices• Right thrust reverser.

The standby system has one electricmotor-driven pump that supplies thethird power source for the ruddercontrol system. The standby systemalso supplies the second powersource for these systems:

• Thrust reversers• Leading edge devices.

FLIGHT CONTROLS

Hydraulic systems A and B supplypower for all three axes of the flightcontrol system.

MULTIPLE FILTRATION

The hydraulic fluid goes throughfilters while servicing and duringoperation of the system to increasereliability.

MODULAR COMPONENTS

Modules reduce the number ofcomponents, connections, andfittings. This makes the system morereliable and easier to service.

SINGLE-POINT SERVICE

CONNECTION

A hydraulic service connection in themain landing gear wheel well makesit possible to service all threereservoirs from one location.

LEAK CONTROL FUSES

The system pressure lines havefuses to protect the hydraulic systemfrom fluid loss if a major componentfails or if a line leaks.

13-2 November 2000

Hydraulic Systems

The three hydraulic systems operateindependently at 3000 psi nominalpressure. The three systems aresystem A, system B, and the standbysystem. Each system has areservoir, pumps, and filters.

The hydraulic fluid is fire resistant.

SYSTEM A

System A uses one engine-drivenpump (EDP) and one electric motor-driven pump (EMDP). The systemsupplies hydraulic power to thesesystems:

• Flight controls• Landing gear• Nose gear steering• Alternate brakes• Flight and ground spoilers• Left thrust reverser• Power transfer unit (PTU).

SYSTEM B

System B uses one EDP and oneEMDP. System B supplies hydraulicpower to these systems:

• Flight controls• Normal brakes• Trailing edge flaps• Leading edge flaps and slats• Right thrust reverser• Flight spoilers• Alternate nose gear steering• Alternate gear retraction.

Regulated air from the environmentalcontrol system pressurizes system Aand system B reservoirs. The airgives a positive supply of hydraulicfluid to each pump. The standbysystem reservoir gets pressure fromfluid in the system B reservoir.

STANDBY SYSTEM

The standby system, which has aseparate electric motor-driven pump,is an auxiliary source of hydraulicpower. To operate the standbysystem, move either of the FLTCONTROL switches to STBY RUDor the ALTERNATE FLAPS switch toARM. The switches are on theoverhead panel. The standby systemalso operates automatically. Standbyhydraulic power supplies pressure tothese systems:

• Rudder control system• Either or both thrust reversers• Leading edge flaps and slats (full

extend only) in the alternate flapmode.

For normal operation, system A andsystem B are on and the standbysystem is off.

Hydraulic System

Ground Spoilers

Rudder

Elevator

Thrust Reversers

LE Slats and Flaps

Aileron Autopilot

Landing Gear

Brakes

TE Flaps

Flight Spoilers

Elevator Feel

Elevator Autopilot

Ailerons

Rudder

Thrust Reversers

Normal

No. 3, 5, 8 & 10

Normal

Normal

Normal

Normal

Normal

Normal

Normal

Normal

ReservoirB

System B

Normal

Normal

Normal

Normal

Normal

Normal

No. 2, 4, 9 & 11

No. 1, 6, 7 &12

Left Engine

PTU

Alternate

Reservoir

System A

A

M

M

E

A

M

M

Right Engine

LE Devices(Extension Only)

NG, MG ActuationNG Steering

StandbyReservoir

Standby System

EDP EMDPElectrical Backup

EDP (Engine-Driven Pump)

Manual Backup

Legend:

EMDP (Electric Motor-

PTU (Power Transfer Unit)

Accumulator Backup

T

E

M

Landing Gear SystemTransfer Valve(For Landing GearRetraction And NG Steering)

Manual Extension

A

EDP EMDP EMDP

T

Driven Pump)

Main Deck CargoDoor (737-700C)

Hydraulics

November 2000 13-3

System Distribution

FLIGHT CONTROLS

Although system A and system Bsupply hydraulic power for theprimary flight controls, either systemalone will operate the ailerons,elevators, and rudder. As a thirdbackup, the ailerons and elevatorscan operate by manual reversion andthe rudder operates by the standbyhydraulic system.

Trailing edge flaps normally receivepower from system B. They alsoreceive power from an electricalbackup system for extension orretraction. The standby systemsupplies a secondary means to fullyextend the leading edge flaps andslats.

The power transfer unit (PTU)supplies a backup source ofhydraulic power for normal and/orautoslat operation. The PTU has ahydraulic motor and pump on acommon shaft. The PTU receivespressure from system A to turn themotor. The pump of the PTUreceives fluid from the system Breservoir. The PTU operatesautomatically when these conditionsare true:

• Airplane in the air• Trailing edge flap position

between up and 15• Engine-driven pump in system B

has low pressure.

Some of the flight spoilers continueto function if either system A orsystem B pressure is not available.

LANDING GEAR AND BRAKES

System A normally supplies pressurefor operation (extension andretraction) of the landing gear.

If engine 1 does not operate fortakeoff, system B supplies pressureto retract the landing gear. Thelanding gear transfer valve changesthe pressure supply for the landinggear from system A to system B. Allof these conditions are necessary forthe landing gear transfer valve toautomatically move to the alternate,system B position:

• Airplane in the air• Landing gear lever not down• One or both main landing gear

not up and locked• Left engine N2 speed less than

50%.

The nose wheel steering systemreceives pressure through the nosegear and main gear actuation.System A normally supplies pressurefor nose wheel steering. The landinggear transfer valve moves manuallyto the alternate (system B) positionwhen these conditions are true:

• Alternate nose wheel steeringswitch to the alternate position

• Airplane on the ground• Normal quantity in the system B

reservoir.

If system A hydraulic pressure is notavailable for extension, the landinggear can be extended manually. Themanual release, in the flightcompartment, lets the landing gearfree-fall to the down and lockedposition.

The normal brake system gets powerfrom hydraulic system B and thealternate is system A. Brakingautomatically transfers to thealternate system if hydraulic systemB pressure is not available.

The normal brake system has abrake accumulator with fluid capacityfor braking when system B andsystem A do not have pressure.

THRUST REVERSERS

System A supplies power to the leftthrust reverser and system Bsupplies power to the right thrustreverser. If there is no primarysystem (A or B) pressure, thestandby system supplies hydraulicpower to operate one or both of thethrust reversers.

13-4 November 2000

System Controls

Controls and indicators for thehydraulic system are on the forwardoverhead panel and the center mainpanel.

ENGINE-DRIVEN PUMPSWITCHES

The ON position is the normalposition for each engine pumpswitch. The depressurizing valvesolenoid does not operate and thevalve closes.

ELECTRIC MOTOR-DRIVEN PUMPSWITCHES

The ON position sends power to theelectric motor-driven pump (EMDP).

PUMP LOW PRESSURE LIGHTS

Amber low pressure lights come onwhen the pump pressure is less thannormal. All low pressure lightsoperate at the same pressure value.

ELECTRIC MOTOR-DRIVEN PUMPOVERHEAT LIGHTS

The amber lights come on for systemA and B EMDPs to show an overheatcondition.

FLT CONTROL SWITCHES

The flight control switches controlhydraulic system pressure toailerons, elevators, rudder, andelevator feel system.

STBY RUD

Either switch A or B in this positionturns on these components:

• The standby pump• Pressurizes the standby rudder

power control unit• Closes the system A or B flight

control shutoff valve.

ON—Normal pressure for eithersystem A or B to flight controls.

OFF—Hydraulic system pressurefor either system A or B stops tothese components:

• Ailerons• Elevators• Rudder• Elevator feel system.

SPOILER SHUTOFF VALVESWITCHES

These valves control hydraulicsystem pressure to the flight spoilers.

• ON—System A or B will supplypower to the flight spoilers

• OFF—No system pressure fromA or B is available to the flightspoilers.

ALTERNATE FLAPS SWITCH

The ARM position operates thesefunctions:

• Turns on the standby pump• Trailing edge flap bypass valve

moves to the bypass position• Arms the alternate flaps control

switch.

STANDBY HYD LOW QUANTITYLIGHT

This light comes on amber when thestandby hydraulic reservoir fluidquantity is less than 50% full.

STANDBY HYD LOW PRESSURELIGHT

This light comes on amber when thestandby pump pressure is too low.The light arms when any one of theseconditions are true:

• Either FLT CONTROL switch inthe STBY RUD position

• The ALTERNATE FLAPS switchin the ARM position

• The standby system operatesautomatically.

HYDRAULIC SYSTEM PRESSUREINDICATORS

These pressure indicators showhydraulic system A and system Bpressure. When both pumps for asystem are off, the indicator showszero pressure. These are the gagepressure ranges:

• Low pressure: 2000 psi• Normal pressure: 3000 psi• Maximum pressure: 3500 psi.

HYDRAULIC BRAKE PRESSUREINDICATOR

The indicator shows brakeaccumulator pressure. It also showsthe accumulator precharge pressurewhen the accumulator completelybleeds off.

• Normal pressure: 3000 psi• Normal precharge pressure:

1000 psi.

SYSTEM RESERVOIR QUANTITYINDICATION

The reservoir quantity for system Aand system B show digitally inpercent of full. The refill level is 76%.When the quantity is 76% or less, anRF message shows adjacent to thequantity indication.

System A (center main panel):

• 100%-Full: 5.7 U.S. gallons (21.6liters)

• 76%-Refill: 4.7 U.S. gallons (16.4liters).

System B (center main panel):

• 100%-Full: 8.2 U.S. gallons (31.1liters)

• 76%-Refill: 6.9 U.S. gallons (23.6liters).

The standby system reservoir has acapacity of 3.5 U.S. gallons (13.3liters). The standby hydraulic lowquantity light (P5 overhead panel)comes on when the quantity is 1.8gallons or less (50% of full).

Hydraulics

November 2000 13-5

LOWPRESSURE

LOWPRESSURE

LOWLOWPRESSURE

OVERHEATOVERHEAT

ON

AON

OFFOFF

HYD PUMPS

ENG 2ELEC 1ENG 1 ELEC 2

B

PRESSURE

ALTERNATE FLAPS

LOWPRESSURE

LOWPRESSURE

FEEL DIFF

B

RUD

OFF

A ON

STBYRUD

OFF

B ON

STANDBY

LOWQUANTITY

HYDFLT CONTROLA

STBY

OFF

ARM

UP

DOWN

OFF

LOWPRESSURE

A BSPOILER

OFFOFF

PRESS

YAW

DAMPER

SPEED TRIM

ON

YAW DAMPER

ON ON

OFF

FAIL

AUTO SLATFAIL

MACH TRIM

FAIL

a

a

a

a

a

Alternate FlapsMaster Switch

StandbyHydraulic LowPressure Light

StandbyHydraulic LowQuantity Light

Flight ControlSwitches

Flight ControlLow PressureLights

Flight SpoilerShutoff ValveSwitches

HydraulicSystem APump Low

System B HydraulicPump Switches

System BOverheat Light

System AHydraulic Pump

System A

HydraulicSystem BPump LowPressure

a

a a

a

a a

aaaa

Overheat Light

Flight Control Panel

Hydraulic Panel

Switches

Pressure Lights

Lights

P5 ForwardOverhead Panel

Hydraulic Systems Controls and Indications

Hydraulic BrakePressure Indicator

PRESSBRAKE

0

4

3

2

1

Hydraulic System AQuantity

Hydraulic System BQuantity

Hydraulic System APressure

RefillMessage

Hydraulic System BPressure

Systems Display

13-6 November 2000

Servicing

All three hydraulic reservoirs fill froma convenient single-point serviceconnection in the right wheel well.These are the main components:

• Hand pump with suction hose• Connection for ground cart

pressure fill• Selector valve.

Electrical power is not necessary toread reservoir fluid quantity. SystemA and B reservoirs have mechanicalquantity gauges that are visible fromthe servicing location.

To fill the hydraulic reservoir,maintenance personnel use either aground cart that connects to thepressure fill connection or the handpump and suction hose.

The system B reservoir fills throughthe standby reservoir. When thesystem B quantity indicator showsfull, both system B and standbyreservoirs are full.

Hydraulic system reliability is betterbecause of filtration. System A and Bhave a pressure, return, and casedrain filters. Individual filters in thesystem supply additional filtration forcritical areas such as flight controlpower units. The standby system haspressure and case drain filters.

Maintenance

Hydraulic system supply and powercomponents are easy to reach. Mostof the hydraulic components are inthe main wheel well. These are thecomponents in the wheel well:

• System A and B EMDP• Three reservoirs• Standby pressure module• Filters• Hydraulic servicing station.

High reliability comes from modularunits which help fluid flow and reducethe number of necessary fittings. Thesystem A pressure module shows asan example. The pressure moduleincludes these components:

• Two pressure filters• Two check valves• Two pressure switches• Pressure relief valve.

Use of this modular assemblyremoves many extra tubes andhydraulic connections.

You can replace the entire pressuremodule or replace individualcomponents without removal of themodule.

Hydraulics

November 2000 13-7

Manual Fill Hand

System A

System A

System B

Reservoir FillSelector Valve

Pump (and Hose)

System B

System BReturn Filter

Reservoir FillPressure Filter

Power TransferUnit (PTU)

PTU Pressure

EDP SupplyShutoff Valve (2)

Reservoir

Module

EMDP

FilterEMDP

System APressureModule System A

Return FilterModule

Reservoir

Main Landing Gear Wheel Well(Looking Forward)

ReservoirPressurizationModule

System BPressureModule

Hydraulic Power Systems Component Locations

Standby PressureModule

Standby

Standby SystemReservoir

System EMDP

Main Landing Gear Wheel WellAft Wing-to-Body Fairing

FWDFWD

Engine Accessory Gearbox

Engine-DrivenPump

13-8 November 2000

Pressure Module

The pressure module supplies andfilters EDP and EMDP pumppressure to user systems. Themodule is on the forward bulkhead ofthe left main gear wheel well. Thepressure module includes thesefeatures:

• Pressure filters• Pump low pressure switches• System pressure transmitter• Pressure relief valve• Check valves.

A non-bypass cartridge type filter inthe pressure line from each pumpfilters the fluid before it goes to theuser systems. The filter has a non-cleanable filter element inside ametal bowl.

A check valve downstream of eachpressure filter and each low pressureswitch isolates them from thepressure output of the oppositepump. The system pressuretransmitter connects to the systempressure module downstream ofboth one-way check valves. Becauseof this, the pressure transmittershows system pressure and notindividual pump pressure. The signalfrom the pressure transmitter goes tothe display electronics unit. You canreplace each component on themodule without module removal.

System A Pressure Module (System B Similar)

EMP Pressure Filter

To Landing GearTransfer Valve

To Alternate BrakeSource SelectorValve and SpoilerControl Valve

System Pressure Transmitter(To Upper Center Display Unit)

EDP Check Valve

To PTU

EDPEMDPPTU

Note:

EDP LowPressure Switch

EMDP LowPressure Switch

EMDP Check ValvePressure LineFrom EMDP 2

System Relief Valve(Engine-Driven Pump)(Electric Motor-Driven Pump)(Power Transfer Unit)

FWD

Landing Gear

November 2000 14-1

• Main Landing Gear

• Nose Landing Gear

• Tires, Wheels, and Brakes

• Brake System

• Antiskid System

• Autobrake System

• Air/Ground System

• Indication and Warning

• Landing Gear Controls

• Brake Controls

Features

MAIN GEAR WHEEL DOORS ARENOT NECESSARY

A blade seal fits around the outboardwheel. The only doors are smallsegment doors attached to the shockstrut. Complicated linkages andactuators are not necessary.

DUAL INDEPENDENT HYDRAULICBRAKE SYSTEMS

Hydraulic system B operates thenormal brake system. Hydraulicsystem A is the primary alternative,and the brake accumulator is thesecondary alternative.

PRESSURE-MODULATEDANTISKID SYSTEM

Provides maximum brake force fordifferent runway conditions.

AUTOBRAKE SYSTEM

The autobrake system applies thebrakes on landing or for a refusedtakeoff (RTO).

NOSE WHEEL STEERING

The pilot’s steering wheel and rudderpedals control the nose wheelsteering.

14-2 November 2000

Main Landing Gear

The main landing gear is a dual-wheel, conventional landing gear. Ithas high operational reliability and alow maintenance design.

The main gear absorbs landingimpacts with a nitrogen-oil strut. Italso absorbs vibrations while theairplane moves on the ground. Theshock and side struts transmit loadsfrom the gear to the airplanestructure.

The only doors on the main gearinstallation are small segmenteddoors attached to the shock strut andhinged to the wing. The doors closewhen the struts retract. The outersurface of the outboard tire alignswith the contour of the airplane toform the aerodynamic fairing for thewheel well opening.

Wheel well blade seals reduce noiseand drag.

The main gear design offers theoperator these advantages:

• Minimum spare inventory• Mechanical gear doors eliminate

sequencing valves and actuators• Easy access to strut servicing

valves.

NORMAL OPERATION

The main landing gear operateshydraulically. Extension uses systemA. Retraction uses system A, orsystem B if necessary.

Overcenter mechanical andhydraulic locks hold the gear in thesepositions:

• Full extension• Full retraction.

MANUAL EXTENSION

The manual extension systempermits landing gear extension ifhydraulic system A has no pressure.A manual gear release from the flightcompartment starts gear free fall tothe down and locked position.

The forces that pull down the gearare gravity and wind loads.

Main Gear Components

Side Strut

Walking

DownlockSprings

Reaction link

Downlock

Uplock Roller

Axle

FWD Jacking Points

Torsion

Main GearActuator

Downlock

Side Strut

Center Door

Inner Door

INBD

Link

Main Gear

Outer Door

Center Door

Inner Door

Link

Main Gear

UplockAssembly

in RetractedPosition

Beam

(Not Shown)

Actuator

Links

BeamHanger

Outer Door

Shock Strut

Gas Charging

Oil Charging Valve(Aft Side Not Shown)

INBD

Valve

Landing Gear

November 2000 14-3

Nose Landing Gear

The nose gear is a dual-wheel typewhich retracts forward and up intothe wheel well.

The nose gear uses a nitrogen-oilstrut. A folding drag brace transmitsloads from the strut to the airplanestructure. At full extension orretraction of the nose gear, the over-center mechanism of the lock linkslocks the drag braces.

The nose wheel well doors operateby mechanical linkages that connectto lugs on the trunnion. The doorsstay open while the gear is down.

NORMAL OPERATION

The nose gear is hydraulicallyactuated. Extension uses system A.Retraction uses system A, or systemB if required.

MANUAL EXTENSION

The nose gear manual extensionoperates by manual release from theflight compartment. The nose gearfree falls to the down and lockedposition when you pull the release.

NOSE WHEEL STEERING

The captain steering wheel controlsthe nose wheel movement to amaximum of 78 degrees in eachdirection. A first officer steeringwheel is optional. The rudder pedalscontrol the nose wheel movement toa maximum of 7 degrees in eachdirection.

Nose gear steering operateshydraulically by system A throughthe landing gear hydraulic extendline.

The steering wheel overrides therudder pedal input. Rudder pedalsteering is not available after thenose gear strut becomes extended.

Centering cams inside the nose gearstrut center the gear beforeretraction.

A dynamic load damper (DLD) in thesteering system reduces vibration.

A towing lever on the steeringmetering valve permits the airplaneto tow throughout the full steeringrange.

ALTERNATE NOSE WHEELSTEERING

If hydraulic system A has nopressure, a switch in the flightcompartment operates the landinggear transfer valve and permitssteering with hydraulic system B.

Nose Gear Components

Jacking Point

Trunnion

Upper DragBrace Link

Nose Gear

Up/Down LockActuator

Door Mechanism

Lock Link

Nose WheelWell Door (2)

Lower DragBrace Link

SteeringActuator (2)

Nose GearActuator

SteeringActuator

Trunnion

Upper DragBrace Link

Nose Gear DoorMechanism

TowingLever

Lower

UpperTorsion Link

TowFitting

Nose WheelWell Door (2)

Gear Extended

ShockStrut

Gas Charging

Lower

Up/DownLock Actuator

Lock Link

Oil ChargingValve

Torsion Link

Valve

Torsion Link

DynamicLoad Damper

14-4 November 2000

Tires, Wheels, and Brakes

The 737-600/700 main gear wheelsuse a standard tire size with anoptional larger tire. The 737-800 isonly available with the larger tire.

The nose gear tire is the same sizefor all models.

The brakes are steel and availablefrom the two wheel suppliers. The737-600/700 use a standard brakeand the 737-800 uses a highcapacity brake.

Fuse plugs in the main gear wheelsact as safety valves if the wheeltemperature becomes too high.Excessive heat caused by unusualheavy use of brakes can causeabove normal wheel temperature.

A pressure relief valve in all wheelsreleases tire pressure if it becomestoo much.

Brake System

The brake system includes multi-discbrakes for each main gear wheel.Hydraulic system B operates thenormal brake system. Hydraulicsystem A is the primary backup andselected by the alternate brakeselector valve if system B fails. If boththe A and B systems fail, theaccumulator isolation valve selectsthe accumulator as the secondarybackup. The brakesystem has thesefeatures:

• Full antiskid protection• Autobrakes for landing or RTO• Easy brake service and

maintenance requirements• Identical brake control from either

pilot station• Directional control through

differential braking

• Hydraulic brake line fuses limitfluid loss if there is a failure(external leak such as a brokenhose to a brake) downstream ofthe fuse. A fuse closes when thevolume of hydraulic fluid throughthe fuse increases more thannormal.

When the gear retracts, the brakesare applied to stop the main gearwheel rotation. Spin brakes in thenose wheel well stop nose wheelrotation when the gear retracts.

Main Gear and Brake Components

Indicator PinBrake Wear

(2)

Pressure Port

AutomaticAdjusterAssembly(6)

Piston/

Rotors &Stators

Brake RetentionCable Attachment

TorqueTakeout Slot

WheelTie Bolts

Outer WheelHalf

Inner WheelHalf

Rotor DriveKeys

WheelBearing (2)

Main Landing Gear Brake Main Landing Gear Wheel

FWD

TorquePin (2)

Main LandingGear Brake

Heat Shield(9)

Shear Bolt(4)

Brake Temperature Sensor(Optional)

Landing Gear

November 2000 14-5

Antiskid System

The antiskid system supplies safebrake control for all runwayconditions. The system protects theairplane from a skid condition causedby a stop of wheel rotation.

The system has a speed transducerin each main wheel. A control unit inthe EE compartment controls boththe antiskid and autobrake systems.The system also has four normalantiskid valves and two alternateantiskid valves.

The antiskid system gets input fromeach wheel speed transducer whenthe wheels roll on the ground. Thesystem automatically controls brakepressure to each main wheel.

If the pilot or autobrake systemapplies sufficient pressure to stopwheel rotation, the control unit readswheel sensor speed inputs andsends applicable signals to the

antiskid valves. The brake pressurereduces to prevent a skid, thenreapplies to an optimum pressure.This operation repeats if skidconditions continue as brakes areapplied.

There is antiskid protection for eachwheel when the normal brake systemoperates. When the alternate brakesystem operates, antiskid protectionis for a pair of wheels.

The ANTISKID INOP amber lightcomes on when a fault in the systemoccurs during these conditions:

• Normal flight operation• BITE test.

The light tells the pilots that antiskidmay not operate when the aircraftlands and brakes are applied.

Ground test features are in theantiskid/autobrake control unit formaintenance.

Autobrake System

The autobrake system automaticallyapplies the brakes to stop theairplane after it lands or if a refusedtakeoff occurs.

The system has a pressure controlmodule in the main landing gearwheel well. The autobrake selectorlets the pilots arm the system andselect the level of auto brake. Acontrol unit in the EE compartmentcontrols the pressure control module.

The AUTO BRAKE DISARM amberlight comes on when the pilot selectsautobrakes and the system has beenmanually disarmed or a malfunctionexists in the autobrake or antiskidsystems.

Brake and Antiskid Systems

Legend:

System B ReturnSystem A ReturnSystem A PressureGear Up Pressure

System B Pressure

ReturnAntiskidValve andMeteringBrakeAlternateFrom Left

Alternate

MeteringValve

BrakeMeteringValve

Brake

Alternate System A PressureSystem B Return

NormalBrakeMeteringValve

PressureGear “Up”

ValveSelectorSourceAlternateAccumulator

IsolationValve

Accumulator

Metering

Alternate

Valve

Brake

FuseHydraulic

ShuttleValve

AntiskidNormal

To System (A)

Normal System B Pressure

Parking BrakeShutoff Valve

(System A)

Return

Normal

BrakePressureSwitch

Right Wheel Brakes

AutobrakeShuttle Valve

BrakePressureSwitch

FuseHydraulic

Left Wheel Brakes

ValveAnti-SkidNormal

ValveAntiskidAlternate

Valve

Return LineFrom RightNormal BrakeMetering Line

ToSystem BReturn

ToSystem AReturn

AutobrakeShuttle Valve

AntiskidNormal

Valve

AutobrakePressureModule

FuseHydraulic

ShuttleValve

FuseHydraulic

FuseHydraulic

FuseHydraulic

AntiskidAlternate

ValveAntiskidNormal

ValveAntiskidNormal

Valve

ShuttleValve

ShuttleValve

14-6 November 2000

Air/Ground System

The air/ground system supplies airand ground mode signals to airplanesystems.

Two air/ground sensors on eachlanding gear monitor thecompression of the shock struts.Sensor signals go to the proximityswitch electronics unit.

The system processes signals fromthe air/ground sensors and sendsair/ground discretes and signals tooperate air/ground relays.

Indication

Position sensors monitor the up andlocked or down and locked positionsof the nose and main landing gears.

Dual sensors at each location on thelanding gear improves dispatchreliability. If one sensor does not

operate, the system will still givecorrect indication.

The proximity switch electronics unitprocesses all position sensor inputsand sends outputs to the landinggear position lights in the flightcompartment.

When the landing gear extends tothe down and locked position, threeprimary and three auxiliary greenlanding gear position lights come on.

Warning

There are two types of warnings forthe landing gear, visual and aural.

VISUAL WARNING

Three red landing gear position lightscome on when the landing gearmoves during extension andretraction and during the gear notdown warning.

The red lights come on for a gear notdown warning when these conditionsare true:

• Landing gear not down andlocked

• Either thrust lever at idle• Altitude below 800 feet or trailing

edge flaps at more than 10 unitsposition.

AURAL WARNING

The proximity switch electronics unitsends a signal to the aural warningunit when any landing gear is notdown and locked and theseconditions are true:

• Either thrust lever at idle• Altitude below 800 feet• Trailing edge flaps extended.

The horn reset switch permits resetof the horn unless the flaps are in thelanding position and landing thrust isselected.

Air/Ground, Indication, and Warning Systems

GEARNOSE

gg

g

RIGHTGEARGEAR

LEFT

AuralWarningUnit

AuralWarningHorn

GEARNOSE

rr

r

RIGHTGEARGEAR

LEFT

GEARNOSE

g

ggRIGHTGEARGEAR

LEFT

Landing Gear Panel (P2)

Landing Gear Indicator

Air/Ground DiscretesAir/Ground Relays

Air-Ground Sensors (6)Position Sensors (12)

Landing GearControl Lever

Position Switch

Flight Control Computers

Trailing Edge Flaps

Position Switches

Horn Reset Switch

Autothrottle Switch Pack

BITEPanel

Proximity Switch Electronics Unit

PSEUa

PSEU Light (P5)

Lights (P5)

Landing Gear

November 2000 14-7

Landing Gear Controls andIndication

There are the landing gear controlsand indications in the flightcompartment:

LANDING GEAR INDICATORLIGHTS

There are one red and two greenindicator lights for each gear.

The red light comes on for theseconditions:

• The gear is not down and lockedand either throttle is not at theidle position

• Gear position does not agreewith the landing gear leverposition.

The green indicator lights come onwhen the related gear is down andlocked.

PSEU LIGHT

When the proximity switchelectronics unit finds a fault, theamber PSEU light comes on.

LANDING GEAR WARNING HORN

The landing gear warning hornoperates when the airplane is in alanding configuration and the mainlanding gear is not down and locked.

The sound from the horn stops whenthe main landing gear is down andlocked.

LANDING GEAR WARNING HORNRESET SWITCH

This switch, on the control stand,stops the warning horn with trailingedge flaps and thrust lever(s) incertain positions. The horn stopsautomatically when the landing gearmoves to the down and lockedposition.

MANUAL RELEASE HANDLES

Three separate handles manuallyrelease all landing gear. Thesehandles are in the flight compartmentfloor behind the first officer.

LANDING GEAR LEVER

This lever has three positions; up,off, and down.

The override trigger overrides theground lockout in the landing gearcontrol lever assembly. The groundlockout prevents the placement ofthe lever to the UP position while theairplane is on the ground.

Landing Gear Controls and Indication

Nose Gear

Landing Gear Panel (P2)

Access

Landing

Landing GearSpeed LimitPlacard

Down and Locked

Indicator Lights (Red)Landing Gear

Right MainGear

Left MainGear

Landing GearIndicator Lights (Green)

In Transit

Gear

Door

Note:

OverrideTrigger

Landing GearWarning HornReset Switch

Lever

Landing Gear Warning Horn

GEARNOSE

gg

g

RIGHTGEARGEAR

LEFT

PSEU Light and Landing Gear

PSEU a

Manual release handlesare on the flight compartmentfloor behind the first officer.

FWD

25-170K

EXTENDALT FLAP40-156K30-165K

15-195K

230K10-210K

5-250K

1-250K

EXTENDED 320K-.82MRETRACT 235K

OPERATING

LEFTGEAR

GEARLEFT

g

r

gGEARRIGHT

rGEARRIGHT

rNOSEGEAR

NOSE

g

GEAR

EXTEND 270K-.82M

2-250K

GEAR

NG

LA

I

N

LANDING GEARLIMIT (IAS)

UP

OFF

D

DN

FLAPS LIMIT (IAS)

Indicator Lights (P5)

14-8 November 2000

Landing Gear Controls andIndication (continued)

These are the controls for nosewheel steering in the flightcompartment.

STEERING WHEEL

The captain steering wheel controlsthe nose wheel steering movementto a maximum of 78 degrees in eachdirection. A first officer steeringwheel is optional. The steering wheeloverrides the rudder pedal input.

A pointer on the steering wheel and aplacard on the sidewall panel showthe amount of steering movement.

RUDDER PEDALS

The rudder pedals control the nosewheel steering movement to amaximum of 7 degrees in eachdirection. Rudder pedal steeringinput backdrives the steering wheel.Rudder pedal steering is not

available after the nose gear strutbecomes extended (the airplane inthe air).

NOSE WHEEL STEERING SWITCH

Nose wheel steering normallyreceives pressure from hydraulicsystem A through landing gearextension. If hydraulic system A hasno pressure, this switch in the flightcompartment operates the landinggear transfer valve and permitssteering with hydraulic system B.

Landing Gear Controls and Indication

RON

MTLA

NOSE WHEEL STEERING

SteeringWheel

Nose Wheel Steering Switch (P1)

Rudder Pedals

Landing Gear

November 2000 14-9

Brake Controls and Indication

HYDRAULIC BRAKE PRESSUREINDICATOR

The indicator shows the pressure ofthe brake accumulator. Normaloperating pressure is 3000 psi.

ANTISKID INOPERATIVE LIGHT

When the antiskid monitoring systemfinds a fault, the amber ANTISKIDINOP light comes on.

PARKING BRAKE LEVER

To set the parking brake, push on thebrake pedals then pull the parkingbrake lever. The parking brakelinkage latches the brake pedallinkage in the pushed down position.The parking brake warning lightcomes on with the brake set.

PARKING BRAKE WARNINGLIGHT

This light comes on red when theparking brake shutoff valve is in theclosed position.

AUTOBRAKE SYSTEM

The autobrake system appliespressure to all the brakes to slow theairplane at the rate selected by thepilot.

The pilot can select one of fourdeceleration levels before landing.The antiskid system operatesnormally during autobrake operation.Manual braking by the pilot willoverride and disarm the autobrakesystem.

The autobrake system also has arefused takeoff (RTO) mode. Thepilot selects RTO prior to takeoff. Thesystem applies maximum brakepressure when the pilot refuses atakeoff.

As in the landing mode, manualbraking overrides RTO. RTOautobrakes disarm at lift-off.

AUTOBRAKE DISARM LIGHT

The amber light comes on when thepilot selects autobrakes and any ofthese are true:

• There is a malfunction in theautomatic brake system

• There is a malfunction in theantiskid system

• The system has been manuallydisarmed.

AUTOBRAKE SELECTOR SWITCH

This switch permits selection of thenecessary level of auto brake andarms the system.

Brake Controls and Indication

Auto Brake/Antiskid

Hydraulic Brake Pressure

Hydraulic Brake

Autobrake

AutobrakeSelector Switch

Pressure Indicator

Antiskid

P10 Control Stand

LandingGearWarningHornCutout

ParkingBrakeLever

Parking Brake

ButtonInoperativeLight

Disarm Light

STABTRIM

TH

RU

ST

INC

RE

AS

E

FLAPT

HR

US

T

INC

RE

AS

E

Light (Red)

PULL

AUTO BRAKE

3

2

1

AUTO BRAKEDISARM a

ANTI SKIDINOP

a

MAXOFF

RTO

ANTI SKID

FLAPDOWN

FLAPUP

PRESSBRAKE

0

4

3

2

1

Panel (P2)

Indicator (P3)

Flight Controls

November 2000 15-1

• Flight Controls

• Lateral (Roll) Control

• Spoiler System andSpeedbrakes

• Directional (Yaw) Control

• Longitudinal (Pitch) Control

• Longitudinal Trim

• High Lift Devices (T.E. Flapsand L.E. Devices)

• Flight Control Switches andIndicators

• Control Stand

Features

The flight control system has controlsurfaces to allow the airplanemovement about all three axes.

HIGH-LIFT DEVICES

High-lift devices supply an increasein lift at slower speeds for takeoff andlanding.

HYDRAULICALLY POWEREDAILERONS AND ELEVATORS

Hydraulic systems A and B operatethe ailerons and elevators. Ifhydraulic power is lost, manualreversion (manual operation of flightcontrols) is available.

HYDRAULICALLY POWEREDRUDDER

Hydraulic systems A and B operatethe rudder. Backup power comesfrom the standby hydraulic system.

ELECTRIC STABILIZER TRIMWITH MANUAL BACKUP

The horizontal stabilizer trim comesfrom an electric motor. Manual trimwheels, on the control stand, arebackup.

HYDRAULIC HIGH LIFT SYSTEMWITH ELECTRIC AND STANDBYSYSTEM BACKUP

The trailing edge flap system and theleading edge flap/slat system usuallyoperate from hydraulic system B.The trailing edge flaps have anelectric motor backup. The standbyhydraulic system is the backup forthe leading edge flap/slat system.

HYDRAULICALLY POWEREDSPOILERS

Hydraulic systems A and B operatethe spoilers.

WHEEL TO RUDDERINTERCONNECT SYSTEM(WTRIS)

The rudder moves automatically forroll coordination during manualreversion of the ailerons (standbyhydraulic system supplies power tothe rudder).

15-2 November 2000

Flight Controls

The flight control system controlsairplane movement around the roll,pitch, and yaw axes.

These are the primary flight controls:

• Ailerons• Elevators• Rudder.

The ailerons control airplanemovement around the roll axis. Theelevators control airplane movementaround the pitch axis. The ruddercontrols airplane movement aroundthe yaw axis.

These are the secondary flightcontrols:

• Spoilers• Horizontal stabilizer• Leading-edge slats and flaps• Trailing-edge flaps.

Primary flight controls usually getpower form hydraulic system A andB. Either hydraulic system cansupply power to all primary controlsurfaces. If A and B systems losehydraulic pressure, aileron andelevator control changes to amechanical backup system (manualreversion). The backup for the rudderis the standby hydraulic system.

Flight Controls

Aileron Balance Tab

Aileron (Typical)

Elevator

Rudder

Stabilizer

Inboard Flap (Typical)

Flight Spoilers (Typical)

Ground Spoiler (Typical)

Leading Edge Flap

Elevator Tab(Typical)

Leading Edge Slats

Outboard Flap (Typical)

Ground Spoiler (Typical)

Roll AxisPitch Axis

Yaw Axis

(Typical)

(Typical)

(Typical)

(Typical) (Not Shown)

Flight Controls

November 2000 15-3

Flight Control Switches andIndicators

LEADING EDGE DEVICESANNUNCIATOR PANEL

An annunciator panel, on the aftoverhead panel, shows the leadingedge flaps and slats position.

The lights come on when the leadingedge devices are in these positions:

• TRANSIT (amber)—Leadingedge devices are in transit, or notin the selected position

• EXT (green)—Leading edge slatsand flaps in extend position

• FULL EXT (green)—Leadingedge slats are in the full extendposition.

All lights go off when the leadingedge devices are in the retractposition.

All leading edge lights come on whenyou push the test switch.

SPEEDBRAKES EXTENDEDLIGHT

This amber light comes on when thespoilers deploy and all of theseconditions occur:

• Airplane in the air• Speedbrake lever is more than

arm position• Trailing edge flaps at or more

than 15 units or altitude is below800 feet.

The amber light also comes on whenthe speedbrake lever is in the downposition when the airplane is on theground and the ground spoilers gethydraulic pressure.

TRAILING EDGE FLAP POSITIONINDICATOR

The indicator is on the P2 centerinstrument panel. Separate pointersshow position of left (L) and right (R)wing trailing edge flaps.

LE FLAPS EXT LIGHT

The green light comes on when theleading edge devices extend to theposition selected by the flap lever.

LE FLAPS TRANSIT LIGHT

When the flap lever moves, thisamber light comes on if the leadingedge devices are in transit or one ormore is not in the selected position.

SPEEDBRAKE DO NOT ARMLIGHT

The amber light comes on when thespeedbrake lever is in the armedposition and there is a malfunction inthe auto speedbrake system.

SPEEDBRAKE ARMED

The green light tells the pilot the autospeedbrake system is ready tooperate.

Flight Control Switches and Indicators

Trailing Edge FlapPosition Indicator

Leading EdgeLeading Edge

Leading EdgeSlat Extend Light

Leading EdgeDevices Transit

Test Switch

Leading Edge SlatFull Extend Light

Leading EdgeFlap Extend Light

DevicesExtended Light

DevicesTransit Light

g

SPEEDBRAKEARMED

aDO NOT ARMSPEEDBRAKE

SpeedbrakeArmed Light

SpeedbrakeDo Not Arm Light

Lights

Flap Position Indicator (P2)

Alert/Annunciator

a

SpeedbrakesExtended

Alert/Annunciator

Light

34

a

g

56

87

SLATS

gg

gg

gg

gg

g

aa

aa

a

EXTFULL

12

TRANSIT

a

EXT

g

SLATS

12

34 g

gg

gg

gg

gg

aa

aa

a

LE DEVICES

TEST

FLAPS

Lights (P3)

Lights (P1)

Leading Edge Devices Annunciator Panel (P5)

SPEEDBRAKESEXTENDED

aTRANSITLE FLAPS LE FLAPS

gEXT

UP

1

5

10

15

25

3040FLAPS

2

15-4 November 2000

Flight Control Switches andIndicators (continued)

The flight control panel on theforward overhead panel has theselights and switches:

• Flight control switches• Standby hydraulic lights• Spoiler switches• Alternat flaps switches• Feel differential pressure light• Speed trim fail light• Mach trim fail light• Auto slat fail light• Yaw damper switch• Yaw damper light.

FLT CONTROL SWITCHES

These switches control hydraulicsystem pressure to the primary flightcontrols. These are the switchpositions for system A and B:

• STBY RUD - Move either switchto this position to turn on thestandby pump and open the

standby rudder valve. Thispressurizes the standby rudderpower control unit.

• ON - In this position there isnormal hydraulic systempressure to the primary flightcontrols.

• OFF - In this position hydraulicsystem pressure is shut off to theailerons, the elevators, therudder, and the feel computer.

STANDBY HYD LIGHTS

The LOW PRESSURE light comeson amber when the standby systempressure is low. The light arms whenthe standby system operates.

The LOW QUANTITY light comes onamber when the standby systemhydraulic fluid quantity is half full orless.

FLIGHT CONTROL HYDRAULICSYSTEM LOW PRESSURE LIGHTS

A LOW PRESSURE light comes onamber when hydraulic pressure tothe primary flight controls is low.

SPOILER SWITCHES

These switches control the positionof the spoiler shutoff valves:

• ON - In this position the spoilershutoff valve opens to supplyhydraulic pressure to the flightspoilers.

• OFF - In this position the spoilershutoff valve closes.


B

RUD

OFF

A ON

STBYRUD

OFF

B ON

STANDBYHYD

FLT CONTROL

ALTERNATE FLAPS

A

STBY

OFF

ARM

UP

DOWN

OFF

A B

YAW DAMPER

SPOILER

OFFOFF

ON ON

YAWDAMPER

OFF

ON

PRESSFEEL DIFF

FAILSPEED TRIM

MACH TRIMFAIL

AUTO SLATFAIL

a

LOWPRESSURE

LOWQUANTITY

LOWPRESSURE

a

Yaw Damper Switch

System B FlightSpoiler Switch

System A FlightSpoiler Switch

Mach Trim Fail Light

Feel DifferentialPressure Light

Control SwitchAlternate Flaps

Alternate FlapsArm Switch

Standby SystemLow Pressure Light

Standby SystemLow Quantity Light

Flight ControlSwitches

Flight ControlHydraulic SystemLow Pressure Lights

Yaw Damper Light

Speed Trim Fail Light

Auto Slat Fail Light


Flight Control Panel

a

a

a

a

aa

a

LOWPRESSURE

Flight Controls

November 2000 15-5

ALTERNATE FLAPS SWITCHES

When the alternate flap arm switch isin the ARM position, these functionsoccur:

• The standby pump suppliespressure

• The TE flap bypass valve movesto bypass

• The alternate flaps control switcharms

• The standby system low pressurelight arms.

If the alternate flaps arm switch is inthe ARM position and you move thealternate flaps control switch, thesefunctions occur:

• DOWN - Electric motor extendsthe trailing edge flaps andhydraulic power extends theleading edge devices.

• OFF - Stops the movement of thetrailing edge flaps but not theleading edge devices. The switchspring loads to OFF from theDOWN position. It remains in theUP position until you put it backto OFF.

• UP - Electric motor retracts thetrailing edge flaps. The leadingedge devices do not retract withalternate operation.

FEEL DIFF PRESS LIGHT

The FEEL DIFF PRESS light comeson amber when the feel computerpressure for system A and system Bare different by more than a givenamount. When the flaps extend, thislight does not come on.

SPEED TRIM FAIL LIGHT

The amber SPEED TRIM FAIL lightcomes on to show a fault of thespeed trim function. See theautoflight chapter for moreinformation about the speed trimfunction.

MACH TRIM FAIL LIGHT

The amber MACH TRIM FAIL lightcomes on to show a fault of the machtrim function. See the autoflightchapter for more information aboutthe mach trim function.

AUTO SLAT FAIL LIGHT

The AUTO SLAT FAIL light comeson to show a fault in the autoslatsystem.

YAW DAMPER SWITCH

The YAW DAMPER switch controlsthe yaw damper. A solenoid holdsthe switch on. The switch springloads to OFF.

When you move the switch to ONafter loss of hydraulic system A andB, the wheel to rudder interconnectsystem (WTRIS) operates.

YAW DAMPER LIGHT

The amber YAW DAMPER lightcomes on when the yaw damper isnot engaged.

15-6 November 2000

Control Stand

These are the controls for the flightcontrols on the control stand.

SPEEDBRAKE LEVER

The speedbrake lever moves flightspoilers up in air or on ground andground spoilers up on ground.

• ARMED - Arms the speedbrakecontrol system for landing

• FLIGHT DETENT - Maximumposition of flight spoilers in air

• UP - Maximum position of flightspoilers on ground

• DOWN - All spoilers stow.

MANUAL STABILIZER TRIMWHEELS

Foldout cranks on each trim wheelpermit either pilot to manually movethe stabilizer.

STABILIZER POSITIONINDICATOR

This shows the position of thehorizontal stabilizer. The green bandshows the permitted takeoff stabilizertrim positions. If you start a takeoffwith the stabilizer out of the greenband range, a takeoff warning hornoperates.

STABILIZER TRIM CUTOUTSWITCHES

These switches are on the controlstand.

• NORMAL - The main electrictrim motor has power available

• CUTOUT - Removes power tothe main electric trim motor.

FLAP LEVER

The flap lever controls the position ofthe leading edge devices and trailingedge flaps. It has nine detentpositions.

RUDDER TRIM SWITCH

The rudder trim switch moves therudder neutral position.

AILERON TRIM SWITCHES

The aileron trim switches move theaileron neutral position. You can seethe amount of trim input on the top ofthe control column.

STABILIZER TRIM COLUMNOVERRIDE SWITCH

This switch is on the control stand.

• NORMAL - Permits stabilizer trimthrough the column switchingmodule

• OVERRIDE - Permits stabilizertrim in both direction if thecolumn switching module fails.

Control Stand

Cutout SwitchesStabilizer Trim

Trim Wheel (2)Manual Stabilizer

Lever (With Indicator)Speedbrake

Top ViewAileron and Rudder

Flap Position Lever(Detented Positionswith Indicator)

Trim ModuleStabilizer Trim Switching ModuleOverride Switch (Column)

StabilizerPositionIndicator (2)

RUDDER TRIM

LEFT RIGHT

NOSERIGHT

NOSELEFT R

UDDER

AILERON

LEFTWINGDOWN

RIGHTWINGDOWN

OVERRIDE

NORMAL

STAB TRIM CAB DOOR

a

CAB DOORUNLOCKED

SwitchesAileron Trim

SwitchRudder Trim

Flight Controls

November 2000 15-7

Roll Control

An aileron on each wing suppliesprimary control around the airplaneroll axis. Two independent hydraulicpower control units (PCUs) move theailerons through cables. One PCUreceives hydraulic power fromsystem A and the other receiveshydraulic power from system B.Either PCU can operate bothailerons to supply roll control. Thereis manual reversion for aileroncontrol with both hydraulic system Aand B off. Aileron balance tabs andbalance panels keep the controlforces to a minimum during manualreversion.

These are the inputs that move theailerons:

• Pilot command• Autopilot command• Aileron trim.

Pilot input to the power control unitsis from the control wheels through acable system. The captain cablesystem is the normal input path.Movement of the power control unitsoperates a wing cable system whichsets the position of the ailerons. Amechanical feel and centering unitwith a centering cam, roller, andspring supplies control wheel feelforce for the pilots.

The autopilot, when engaged,controls the ailerons throughautopilot actuators. These actuatorssupply input to the power controlunits and backdrive the controlwheels.

The aileron trim switches on the aft ofthe P8 aft electronic panel control theaileron trim. The trim switchescommand an electrical linearactuator which moves the feel andcentering unit.

Four flight spoilers on each wingoperate with the ailerons. When thecontrol wheel turns, the spoilersoperate to help the roll movement ofthe airplane. Hydraulic system Aoperates flight spoilers 2, 4, 9, and11. System B operates flight spoilers3, 5, 8, and 10.

The flight spoilers also supply lateralcontrol if there is a malfunction in theaileron system. If a malfunctionoccurs, the first officer spoiler cablesystem controls the flight spoilersthrough an transfer mechanism.

The flight spoilers can also operateas speed brakes. This function is inthe spoiler system description.

Aileron and Flight Spoilers (Roll) Control System

Control Unit (2)Aileron Power

System AActuatorAutopilot

System BActuatorAutopilotAileron

Spoiler Mixer &

Flight Spoilers

TransferMechanism

Trim Indicator(Top of Both

Normal Lateral Control Input(Captain Cable Only)

Flight Spoilers

Balance Tab

Aileron cableQuadrants (2)

Aileron TrimActuator

(Typical)

(Typical)

Columns)

ControlWheel (2)

Ratio Changer

Aileron Feel andCentering Unit

Flight Spoiler Control Input(First Officer Cable Only)

15-8 November 2000

Spoiler System and Speedbrakes

There are four flight spoilers and twoground spoilers on each wing. Theflight spoilers operate in the air andon the ground. They help the aileronswith lateral control and also operateas speedbrakes to increase drag anddecrease lift. The ground spoilersoperate only on the ground todecrease lift and increase drag.

The speedbrake lever controls theflight spoilers in the air. The amountthat the spoilers move depends onboth the control wheel position andthe speedbrake lever position. Amechanical spoiler mixer and aspoiler ratio changer give the correctspoiler extension on each wing fromthe two inputs. Aerodynamic forcescan override actuator hydraulicpressure and limit spoiler panelextension to an amount in proportionto airspeed.

There are two ground spoilers oneach wing. One ground spoiler isoutboard of the flight spoilers theother is inboard of the nacelle. All theground spoilers receive hydraulicpower from system A. A groundspoiler interlock valve, operated bythe right main gear strut, permitsground spoiler use only on theground.

The ground and flight spoilersoperate together on the ground. Thespoilers extend to reduce lift andincrease aerodynamic drag. Thishelps stop the airplane in a shorterdistance.

The spoilers operate eitherautomatically or manually on theground. Use the speedbrake lever tooperate the spoilers manually. Thespoilers extend automatically underthese landing conditions:

• Speedbrake lever is in the armedposition

• Airplane on the ground or wheelrotation is more than 60 knots.

All spoilers automatically retract,after automatic extension, wheneither thrust lever advances. Theflight crew can manually move thespeedbrake lever to override theautomatic spoiler system.

During a refused takeoff (RTO), thespoilers extend if these twoconditions occur:

• One of the two reverse thrustlevers operates

• The airplane speed is more than60 knots.

Spoiler System

Ground Spoiler Interlock Valve

Ground Spoilers - 1, 6, 7, and 12Flight Spoilers - 2, 3, 4, 5, 8, 9,10, and 11

Speedbrake Lever Flight Spoiler

Ratio Changer

Speedbrake Quadrantand Electric Actuator

(Operated By Push-PullCable-Right Gear)

Quadrant (Typical)

Ground Spoiler Control Valve(Operated By Spoiler Mixer)

Spoiler Mixer

Note:

Speedbrake

12

34

5

6

7

89

1011

12

Quadrant

Flight Controls

November 2000 15-9

Rudder (Yaw) Control

The rudder gives control of theairplane around the yaw axis. Therudder is a single conventionalrudder without tabs. The normalmovement of the rudder is from themain rudder power control unit whichuses hydraulic systems A and B. Aseparate power control unit, whichuses standby hydraulic power,supplies backup movement. Any ofthe three hydraulic systems supplyrudder control. Either pilot's rudderpedals operate the power controlunits through cables. A mechanicalfeel and centering unit gives the pilotfeel forces and centers the rudder.

An electric actuator on the feel andcentering unit supplies rudder trim. Atrim control switch on the aisle standoperates the trim actuator. Trimactuator movement gives an input tothe power control unit (PCU) to movethe rudder.

The yaw damper system moves therudder to prevent dutch roll. Thissystem operates through thehydraulic system B control section ofthe main rudder power control unit.The yaw damper operatesindependently of the rudder controlsystem and does not give feedbackto the rudder pedals.

The wheel to rudder interconnectsystem also controls the rudderthrough the standby power controlunit. It is active only when hydraulicsystems A and B do not havepressure. Movement of the controlwheel sends a signal to the standbypower control unit to move therudder. This gives rudder assist tohelp turn the airplane when control ofthe ailerons is through manualreversion.

Rudder (Yaw) Trim and Control System

Adjustment Crank (Typical)Rudder Pedal

StandbyRudder PCU

Feel andCentering Unit

Input Rod From RudderAft Control Quadrant

ActuatorRudder Trim

Aft ControlQuadrant

Rudder

Captain’sRudder Pedals

Trim Controland Indicator

Main Rudder PCU(Both A and B

(Aft Section of theCenter Aisle Stand)

Rudder ControlCables

Systems)

15-10 November 2000

Elevator (Pitch) Control

The elevators supply primary controlabout the airplane pitch axis. Twoelevators connect to the aft end ofthe left and right horizontal stabilizersections. Two independent hydraulicpower control units (PCU) move theelevators. One PCU receiveshydraulic power from system A andthe other receives hydraulic powerfrom system B. Either power controlunit can operate both elevators tosupply pitch control.

These are the inputs that move theelevators:

• Pilot command• Autopilot command• Neutral shift• Mach trim.

Pilot input is from the control columnsthrough a dual cable system and aninput torque tube. The input torquetube connects to each PCU with twoinput rods. An output torque tubeconnects both power control units toboth elevators. A hydraulic feelsystem supplies control columnforces proportional to airspeed andstabilizer position. An elevator feelcomputer gets input of airspeed andstabilizer position and supplies theappropriate feel force. There ismanual reversion for elevator controlwith hydraulic system A and B off.

The autopilot, when engaged,controls the elevators throughautopilot actuators. These actuatorsmove the input torque tube whichsupplies input to the power controlunits.

Neutral shift moves the elevators togive a different elevator neutralposition for different stabilizerpositions. Neutral shift rods connectthe stabilizer to the elevator feel andcentering unit. The elevator’s neutralposition changes as the stabilizermoves.

The mach trim system commandsthe elevators at high speeds. Themach trim actuator moves theelevator feel and centering unit. Thischanges the elevator neutralposition.

A stick-shaker stall warning systemgives the pilot the positive indicationthat the airplane is close to a stall. Anelectric motor attached to eachcontrol column shakes the columnwhen the airplane comes near a stallcondition.

Elevator (Pitch) Control System

Autopilot

Mach TrimActuator

Feel and

Elevator PCUSystem B

First Officer’sInput Quadrants

Captain’s CableInput Quadrants

Elevator PCUSystem A

ActuatorSystem B

Output TorqueTube

Input TorqueTube

Left ElevatorInput

Right ElevatorInput

AutopilotActuatorSystem A

Centering Unit

ControlColumn (2)

BreakoutMechanism

BalanceWeight (2)

ForwardControlQuadrant (2)

Control ColumnStick-Shaker (2)

Flight Controls

November 2000 15-11

Stabilizer Trim

The moveable horizontal stabilizergives pitch trim to the airplane. Thehorizontal stabilizer is a three pieceassembly. A jackscrew assemblyattaches to the center section. Thejackscrew moves the stabilizerassembly. These are the inputs thatcontrol the jackscrew:

• Main electric trim inputs to thestabilizer trim motor

• Autopilot and speed trim inputs tothe stabilizer trim motor

• Manual trim wheels throughcables.

Thumb switches on either controlwheel command the stabilizer trimmotor for the main electric trimsystem. The motor operates at lowspeed with flaps up and high speedwith flaps not up.

The autopilot and speed trimsystems also give commands to thestabilizer trim motor. The autopilottrim motor speeds are slower thanthe thumb switch control speeds.

The electric trim system includes acolumn switch module to stopuncommanded stabilizer trim. If thepilot moves the control columnopposite to the direction of theuncommanded trim, switches in themodule stop the electric trim. Anoverride switch on the aisle standbypasses the column switch moduleif it malfunctions.

The manual stabilizer trim controlwheels connect to the stabilizergearbox with a forward and aft cabledrum. Foldout handcranks on thetrim wheels allow either pilot tomanually trim the stabilizer. Thecable system also operates trimposition indicators next to the trimwheels on the control stand.

Stabilizer (Pitch) Trim and Control System

Column Switching

Trim Position

Stabilizer Drive

Aft Cable

Stabilizer Support

Forward

Structure

Wheels

Gearbox

(Center Section)

Drum

Cable Drum

Modules (2)

15-12 November 2000

High Lift Devices

The high lift devices improve wingperformance at low speeds. The highlift system includes leading edgeflaps and slats and double-slottedtrailing edge flaps. Hydraulic SystemB supplies power to the leading edgedevices and the trailing edge flaps.

Trailing edge flaps have double-slotted inboard and outboardassemblies on each wing. Eachassembly includes two mechanicallylinked segments that extend andseparate to form a double-slottedsurface for added lift. A hydraulicmotor drives a flap power drive unit(gearbox) to operate all trailing edgeflaps. A torque tube drive systemtransfers movement from the flappower drive unit to the flaps.

Leading edge devices have twoleading edge flaps inboard of eachengine and four leading edge slatsoutboard of each engine. To extend

the leading edge devices, move theflap control lever on the controlstand.

The leading edge flaps and slatsretract with the flap lever in the 0position. The leading edge flapsextend with the flap control lever inany position from 1 to 40. Theleading edge slats move to an extendposition with a flap lever positionfrom 1 to 5. The slats move to a fullextend position with a flap leverposition from 10 to 40.

Autoslat operation automaticallymoves the slats from extend to thefull extend position if the airplaneapproaches a stall. Normal operationof the leading edge flaps and slatscomes from hydraulic system B.However, if the engine driven pumpfor system B has low pressure andthe trailing edge flaps are in takeoffposition, the power transfer unit(PTU) automatically supplies abackup source of hydraulic system B

power for normal and/or autoslatoperation.

The flap alternate operation useselectric power to drive the flapsystem if a failure prevents normalhydraulic operation.

The hydraulic pressure shuts off tothe hydraulic motor if any of theseconditions occur:

• Flaps become asymmetric• Flaps become skewed (inboard

end of a flap does not align withoutboard end of flap)

• Flaps have an uncommandedmotion (UCM)

• Flaps operate with the alternatedrive.

Takeoff flap positions supply high liftwith low drag. Landing flaps producehigh lift and high drag which help todecrease approach speeds.

High Lift Devices Range of Position

LE Flaps1 and 2

OutboardFlap TrackFairing (4)

Slats 1-4

Flap PositionTransmitter

Slats 5-8

Flap Control Unit

LE Flaps3 and 4

Flap ControlLever

Flap Power Unit

InputCables

Drive SystemTorque Tube

Outboard FlapTransmission (4)

LE Slat

LE Slat(Not Shown)

(Not Shown)

0

1

2

5

10

15

25

30

40

High Lift Devices Range of Position

LE Flaps

0

1-40

Extend

Full Extend

Cruise

Takeoff

Landing

Flap Lever Settings

(Typical)

Flight Controls

November 2000 15-13

The flap load relief system protectsthe trailing edge flaps from excessiveairloads. The flaps move up oneposition for these conditions:

• Flaps are at 30 or 40 units• Airspeed exceeds a set speed.

The flaps return to the selected flapposition when airspeed reduces.

The flap design helps with durabilityand maintainability. The heavy-gagelower surface skin improves damagetolerance.

Flap Operation

For normal operations, the pilotselects the desired position with theflap lever on the control stand. Bothleading edge devices and trailingedge flaps travel to the positionselected. The possible flap leverpositions are: UP, 1, 2, 5, 10, 15, 25,30 and 40 units.

An alternate system operates whenthe normal hydraulic source (systemB) is not available for leading edgeand trailing edge operation. Thestandby hydraulic system suppliespower during alternate operation tomove the leading edge devices to thefully extended position. An electricmotor supplies power duringalternate operation to move thetrailing edge flaps. The alternate flaparming switch and the alternate flapscontrol switch on the forwardoverhead panel operate the trailingedge flaps and leading edge devices.

HIGH LIFT DEVICES INDICATION

An indicator on the center maininstrument panel shows the trailingedge flap position. A flap positionindicator has a right wing and leftwing flap pointer. A green LE FLAPSEXT light on the center maininstrument panel comes on when allleading edge devices are in theselected position. An amber LEFLAPS TRANSIT light comes onwhen any of the leading edgedevices are in transit or not in theselected position. An annunciatorpanel, on the aft overhead panel,shows each leading edge flap or slatposition.

Environmental Systems

November 2000 16-1

• Pneumatic

• Air-Conditioning

• Conditioned Air Distribution

• Equipment Cooling

• Cargo Compartment Heating

• Pneumatic and Air-Conditioning Control Panels

• Cabin Pressure Control

• Cabin Pressure Control Panels

Features

PNEUMATIC

These sources supply the pneumaticmanifold:

• Engine bleed air• APU bleed air• Ground source.

The system controls and indicationsreduce crew workload.

AIR CONDITIONING

The air conditioning system is a dualair cycle pack design.

The ram air system producesminimum drag.

The pack air-cycle machines have airbearings. These bearings require noregular servicing.

Pack temperature control is eitherautomatic or manual. Automaticovertemperature protection reducescrew workload.

System maintenance does notrequire ladders or special stands.

A cabin air recirculation systemreduces fuel consumption.

EQUIPMENT COOLING

The airplane uses two equipmentcooling systems. Both systems havebackup fans.

The equipment cooling systemautomatically configures for groundand flight operations.

CARGO COMPARTMENTHEATING

The forward cargo compartmentheating is by exhaust air from theequipment cooling system.

The aft cargo compartment heatingis by outflow air from the passengercabin.

PRESSURIZATION

The cabin pressure control systemuses dual, automatic, digitalpressure controllers. This increasesreliability and reduces crewworkload.

Pressure controllers have BITE.

There is a manual backup pressurecontrol system.

Independent, mechanical safetyrelief valves protect the airplanestructure in any mode of pressurecontrol.

16-2 November 2000

Pneumatics

The pneumatic system suppliespressurized air to these systems andcomponents:

• Engine starters• Air conditioning packs• Thermal anti-ice systems• Hydraulic reservoirs• Potable water system.

These are the sources of pneumaticpower:

• External ground source• APU load compressor• Engine bleed air.

The APU regulates bleed airpressure from the APU loadcompressor. The APU is a primarysource of bleed air on the ground. Iteliminates the need for groundsupport equipment. The APU is abackup source of bleed air in flight.

Engine bleed air comes from the 5thor 9th stage of the high pressurecompressor. The change from 5th to9th is automatic. The pressureregulating and shutoff valves(PRSOVs) regulate engine bleed airpressure.

The precooler system cools theengine bleed air. The precooler is anair-to-air heat exchanger. It coolsengine bleed air with engine fan airas the heat sink. The precoolercontrol valve controls the flow of fanair.

The isolation valve isolates thepneumatic manifold into a left andright side when closed. Thisseparates the pneumatic system intotwo systems. A single duct failurecan be isolated. It will not effect theentire system. When open, the valvegives continuity to both sides of thepneumatic manifold. This allows asingle source to power systems onone or the other side of the manifold

(e.g. engine starting operations). Theisolation valve operation can beautomatic or manual.

Pressure transmitters and a gage onthe P5 panel show right and leftmanifold pressures.

The pneumatic system control isfrom the P5 panel. Improvements ofcontrols and indications decreasecrew work load.

Automatic overtemperature andoverpressure protection systemsprotect the airplane from systemmalfunctions.

Overheat sensing elements near thepneumatic ducts monitor the systemfor duct leaks.

Pneumatics

Valve

Control Valve

Check

From APU

BleedValve

Apu

ValvePack

ValveWing Anti-ice

Precooler

Precooler

ReliefValve

ConditioningSystem

To Left Air

PressureTransmitter

ValveIsolation

Pneumatic GroundService Connector

Fan

9th

5th

Fan

9th

5th

Motor Operated Valve

Solenoid Controlled Valve

To Starter

PressureRegulating andShutoff Valve

High StageValve

To LE Slats

S

M

S

S

S

S

M

S

2

Hydraulic ReservoirPressure Tap

Potable WaterPressure Tap

2

1

1

2


November 2000 16-3

Air Conditioning 737-600/700

The air conditioning system uses twoindependent air-cycle cooling packs,a cabin temperature control system,an air distribution system, and arecirculation system.

The system can maintain safe cabinconditions with any one subsysteminoperative.

The air conditioning packs are underthe wing center section.

The air conditioning packs dischargeinto the mix manifold of thedistribution system. Air conditioningpack discharge is used for thesepurposes:

• Supply fresh air to the cabin at acomfortable temperature

• Pressurize the airplane• Cool the electronic equipment• Heat the cargo compartments.

The pneumatic manifold suppliescompressed air to the airconditioning packs. The flow controland shutoff valves control the air flowthrough the packs.

Heat exchangers and expansionthrough an air-cycle machine (ACM)cools pack air. The ACM is arefrigeration turbine and has airbearings. No scheduledmaintenance is necessary.

On the 737-600/700, the mix valvecontrols pack output temperature.This valve mixes cooled anduncooled pack air to producedischarge air at the propertemperature. The 35F control systemprevents freezing temperaturesdownstream of the ACM. Thisprotects the system from icedamage.

A water separator removescondensation from the cooled air

stream. The water sprays into theinlet of the ram air system.

The ram air system supplies acooling flow of ambient air throughthe heat exchangers. This airstreamis the heat sink for the pack system.The ram air system inlet panels moveto keep drag to a minimum. Duringground operations, the ACM ram airfan pulls air through the system.

Improvements of controls andindications on the P5 panel decreasecrew work load. There is manual andautomatic control of pack flow rates.Temperature control is alsoautomatic or manual. An automaticoverheat protection system is activein all modes of operation.

The temperature regulator and 35Fcontrol system have BITE.


Water Spray NozzleHeat Exchanger

Ram AirExhaust

Ram Air Inlet

Ram Air Duct

Air Cycle Machine

Water Separator

Mix Muff

Pack Discharge

35F Control System

Check ValveMixValve

Flow Control

ControlSignals

P5Module

TempRegulator

TempSensors

OverheatSwitches

Electronic

Solenoid

MotorM

S

M

Ram Air System

(Typical)

Control

SM

Air CondRelays

and ShutoffValve

(Typical)

16-4 November 2000


The air conditioning system uses twoindependent air-cycle cooling packs,a digital 3-zone cabin temperaturecontrol system, an air distributionsystem, and a recirculation system.

The system can maintain safe cabinconditions with any one subsysteminoperative.

The location, purpose, function, andintegration of the 737-800/900system is similar to the 737-600/700system.

The flow control and shutoff valvescontrol air flow through the packs.

Heat exchangers and expansionthrough an air cycle machine (ACM)cools pack air. The ACM has airbearings. Scheduled maintenance isnot necessary.

System temperature control isautomatic by the pack temperaturecontrol valves and trim air valves.

Two digital pack/zone controllersoperate these components:

• Temperature control valves• Trim air valves• The ram air actuators.

On the 737-800/900, the normalpack output temperature control is bythe temperature control valve (TCV).The standby temperature controlvalve can control pack outputtemperature if the normal systemfails. The temperature control valvescontrol the amount of pack air thatdoes not flow through the coolingcomponents of the pack. Thisproduces the proper dischargetemperature. The cabin zone thatrequires the coolest air sets the packoutput temperature. Hot trim air isthen added to the ducts for the othertwo zones.

The pack has a high pressure waterextractor system. This system has areheater/condenser/extractorassembly. This removes the waterbefore it enters the ACM turbine.

The ram air system supplies acooling flow of ambient air throughthe heat exchangers. The ram airsystem inlet panels move to keepdrag to a minimum.

Improvement in controls andindications on the P5 panel reducecrew work load. There is manual andautomatic control of pack flow rates.Temperature control and overheatprotection is automatic.

The digital pack/zone controllershave LRU BITE.


AirCond.Relays

DigitalPack/ZoneControllers

P5Module

TrimAir PressReg Valve

StbyTCV

TCV

Flow Control

Ram AirFan

Ram AirActuator

Reheater

Condenser

Water Extractor

Check Valve

Heat Exchanger(Typical)

Trim Air Valve (Typical)

Flight Compartment Zone

Forward Pass Zone

Aft Pass Zone

ACM

Water Spray

ControlSignals

TemperatureSensors

OverheatSwitches

Ram AirInlet

Ram AirExhaust

FromOtherPack

(Typical)

PackDischarge

Nozzle

Ram Air Duct

S

M

M

M

M

S

M

and ShutoffValve


November 2000 16-5

Conditioned Air Distribution

GENERAL

The conditioned air distributionsystem combines the air conditioningpack outputs with recirculated air. Itthen distributes the air to the flightcompartment and the passengercompartment.

The mixing manifold andrecirculation components are aft ofthe forward cargo compartment.

The737-600/700 distribution systemhas these two independenttemperature control zones:

• Flight compartment• Passenger compartment.

The 737-800/900 distribution systemhas these three independenttemperature control zones:

• Flight compartment• Forward passenger compartment

• Aft passenger compartment.

FLIGHT COMPARTMENT

The flight compartment receivesconditioned air from the left packdischarge.

If the left pack is off, the flightcompartment receives air from theright pack and the mix manifold.

Outlets and controls in the flightcompartment supply conditioned airfor these functions:

• Windshield defogging• Foot warming• Seat warming• Shoulder warming• Control panel gaspers• Ceiling panel gaspers and

anemostats.

Flight compartment air then movesthrough vents into the electronicequipment compartment.

PASSENGER COMPARTMENT

Conditioned air from the mixmanifold moves in sidewall ducts toan overhead distribution duct abovethe center isle. The air comes outthrough these devices:

• Overhead duct nozzles• Window diffuser outlets• Passenger gasper outlets• Galley ceiling gasper outlets• Lavatory gasper outlets.

Passenger compartment air thenmoves through air return grills. Thisair then goes through a filteredrecirculation system or goesoverboard through the outflow valve.

Galley air goes overboard throughfuselage vents.

Conditioned Air Distribution

Air Conditioning Packs

Diffuser Outlet

Equipment RacksElectronic

DistributionFlight Deck

ControlsAir Conditioning

Mix Manifold, Recirculation Fan and Filter

Overhead Distribution DuctPassenger Compartment

737-600/-700 Shown 737-800/900 Similar

Sidewall Risers(Three on 737-800/900)

(Two Fans and Filters on 737-800/900)

System

(Typical)

16-6 November 2000

Equipment Cooling

GENERAL

Electronic equipment is air cooled.

These systems supply air to theequipment cooling system:

• The supply system• The exhaust system.

Cooling for the most criticalelectronic equipment is from bothcooling systems. This causes adouble (push-pull) cooling system.Cooling for less critical equipment isby one system. Electronic equipmentthat does not require active cooling isnot included in the cooling system.

Each system has two parallel fans(normal and alternate). Flowdetectors monitor the quality ofcooling air flow and give an indicationof a failure. If the normal fan fails, theflight crew can select the alternatefan.

The fans, air filter, and the overboardexhaust valve are in the electronicequipment compartment. The flowdetectors are in ducts in the forwardequipment compartment.Connecting ducts, equipment rackchannels, headers, and plenumscomplete the cooling circuits.

Controls and indications are on theP5 forward overhead panel.

SUPPLY SYSTEM

The supply system pulls cooling airthrough a cleaner and pushes it overthese components:

• Pilot primary displays (3)• Pilot control stand• E1 and E5 racks• Transverse rack.

The supply system pushes air overthe equipment and into the exhaustsystem or into the electronicequipment compartment.

EXHAUST SYSTEM

The exhaust system pulls cooling airover these items:

• Pilot primary displays (3)• Pilot control stand• P6 panel• P5 panel• E1 and E5 racks• Transverse rack.

The exhaust system air thendischarges through an overboardexhaust valve, overboard. In flight,differential pressure causes thisvalve to close. These things happenwhen the valve closes:

• Diverts warm equipment exhaustair around the forward cargocompartment for cargo heating

• Increases airplane pressurizationcontrol.

Equipment Cooling System

Supply Fans

Exhaust Fans

Flow DetectorsSupply Air Filter

Overboard

Supply System

Exhaust System

Pilot Primary

PilotE1 Rack Transverse Rack

E5 Rack

Duct (Typical)

Display (Typical)

Duct (Typical)

(E2,E3,E4)

Control Stand

P5 Panel

P6 Panel

E2

E3

E4

ExhaustValve


November 2000 16-7

Cargo Compartment Heating

GENERAL

The cargo compartments are notventilated. There are sealed, fireresistant liners that prevent oxygenfrom sustaining a fire in a cargocompartment.

The volume of air in the cargocompartments is sufficient to sustainthe life of animals with theseconditions met:

• The biomass is not too great• The flight duration is not too long• The cargo volume does not

displace too much air space.

Conditioned air circulated around thecargo liners warms the cargocompartments. This keeps thecompartments warm enough tosustain life.

The cargo heat system is passive. Ituses the differential pressures andheat energies of the air conditioningand pressurization systems.

Cargo heating is automatic andcontrols, indications, or servicing arenot necessary.

FORWARD CARGOCOMPARTMENT

The forward cargo compartment isheated only when the airplane is inthe air.

AFT CARGO COMPARTMENT

The aft cargo compartment is heatedwhen the airplane is in the air and onthe ground.

A-A B-B

Air Return Grille

Diffuser Outlets

Compartment

Aft CargoCompartmentForward Cargo

Outflow

B

B

A

A

(Typical)

(Typical)

Valve

Overboard

Cargo Compartment Heating

Exhaust Valve

16-8 November 2000

Pneumatic and Air ConditioningControl Panels

GENERAL

The control panels are on the P5forward overhead panel.

These are control panel features:

• Lighted gages• Light plates• Positive position toggle switches

and selector knobs• System condition and caution

lights.

PNEUMATIC CONTROLS

Toggle switches control thesefunctions:

• Bleed air sources• Pneumatic manifold isolation.

A dual needle pressure gage showsright and left duct pressures.

System indication lights show theseconditions:

• Bleed trip off• Wing-body overheats (duct

leaks)• Dual bleed• Loss of equipment cooling.

Push-button switches control:

• Resets of trip off conditions• Wing-body overheat tests.

AIR CONDITIONING CONTROLS737-600/700

Switches control these functions:

• Pack flow scheduling• The right recirculation fan• The equipment cooling fans.

Temperature selectors giveautomatic or manual packtemperature control for the twozones.

Gages show the mix valve position.A temperature gage and sourceselector show the systemtemperatures.

System lights show these conditions:

• Pack trip off• Duct overheats• Ram door position.

AIR CONDITIONING CONTROLS737-800/900

The higher capacity three-zonetemperature control system of the737-800/900 uses these additionalcontrols:

• Left recirculation fan switch• Three temperature selectors• Three zone temp lights for

overheat and fault indication• Trim air system control switch.

AIR TEMP

Pneumatic and Air Conditioning Control Panels

737-600/700

TRIM AIR

CONT CAB AFT CABFWD CAB

OFF OFF OFF

OFFa

OFFa

EQUIP COOLING

EXHAUSTNORM

ALTN

DUALBLEED FULL OPEN

RAM DOOR

TRIP OFFPACK

OVERHEATWING-BODY

BLEEDTRIP OFF

RAM DOORFULL OPEN

40

100

80

60

0

20

PSI

ANTIWING

ICEANTIICE

WING

OFFOFF

ON ON

RESET

OFFAUTO

OPEN

TEST

AUTO

OFFAUTO

HIGH HIGH

AUTO

OFF

ISOLATIONVALVE

R PACKL PACK

2APUBLEED

1

TRIP

RECIRC FAN

OVHT

DUCTOVERHEAT

COOL

COOLOFF

MANUAL

WARM

WARM

AUTO

DUCT

SUPPLYCABIN

PASSAIR MIXVALVE

AIR MIXVALVE

AIR TEMPCONT CABIN PASS CABIN

200

160120

40 F

80

TEMP.

Air Conditioning Panel

Equipment CoolingPanel

737-800/900

Cabin Temperature Panel

P5 Forward OverheadPanel

ZONECAB

ZONETEMP a

ZONETEMP a

ZONETEMP a

OFF

ON

PACK

SUPPLY

DUCT

AUTOAUTOAUTO

C WCC WW

FWD

CONTCAB

AFT AFT

R

L

FWD

TEMP60

80

100

40

20

C

COOL

COOLOFF

MANUAL

WARM

WARM

AUTO

TRIP OFFPACK

OVERHEATWING-BODY

BLEEDTRIP OFF

DUCTOVERHEAT

SUPPLY


November 2000 16-9

Cabin Pressure Control

NORMAL OPERATION

The pressurization system controlsthe rate of air released from thecabin. The position of the outflowvalve controls this rate.

The cabin pressurization systemmaintains a safe, comfortable cabinpressure altitude at all times. Undernormal operations, cabin pressurealtitude is never more than 8,000feet.

The pilots can control airplanepressurization in these modes:

• Automatic mode• Alternate mode• Manual mode.

Controls for pressurization andindication are on the P5 forwardoverhead panel.

Two digital controllers are in the EEcompartment. The controllers haveLRU BITE. They use inputs fromthese to control cabin pressure:

• P5 panel settings• Stall management computers• Air data computers• Aft outflow valve position

transducer.

In the automatic modes (auto andalternate), the controllersautomatically schedule cabinpressurization for all phases of flight.If both controllers fail, the pilot cancontrol the valve manually.

The outflow valve is in the aft, lowerright area of the airplane.

PRESSURE EQUALIZATION

Independent mechanical pressureequalization valves are in thebulkheads of the cargocompartments to allow for pressurechanges in the cargo compartments.

FAIL-SAFE DEVICES

If the systems fail, these valvesprotect the airplane structure fromexcessive pressure differentials:

• Positive pressure relief valves (2)• Negative pressure relief valve• Cargo compartment blowout

panels.

ALTITUDE WARNING

A cabin altitude warning system tellsthe crew when the cabin pressurealtitude goes to 10,000 feet. Thissystem activates by a switch on theceiling of the lower nosecompartment. It operates an auralwarning horn on the control stand.The horn cutout button is on the P5forward overhead panel.

Cabin Pressure Control

Pressurized Area

Negative Relief Valve

Outflow Valve

PressureRelief

P5 Forward OverheadPanel

Valves (2)

Pressure Equalization

Blowout Panels

Digital CabinPressure

Outflow Valve

Pressurization Control Panel

Manual Signal

Auto Signal

EVLAV

MANUALAUTO

LAND ALT

FLT ALT

AUTOALTN

MAN

ESOLC

NEPO

(Typical)

Valves (Typical)

Digital Cabin PressureControllers (2)

gMANUAL

a a gDESCENTFAILAUTO OFF SCHED ALTN

Positive

Controller (2)

16-10 November 2000

Cabin Pressure Control Panels

GENERAL

The pressurization control panels areon the P5 forward overhead panel.

These are the control panel features:

• Lighted indicators• Light plates• Selectors• LCD numerical displays• Toggle switch• Push-button switch• System indication and warning

lights.

PRESSURIZATION CONTROLS

There are controls for thesefunctions:

• Pressurization mode• Flight altitude• Landing altitude.

LCD digital displays show thesesettings:

• Flight altitude• Landing altitude.

There is a flight altitude/cabin altitudeconversion placard below thecontrols. Manual calculations are notnecessary.

A takeoff pressure differentiallimitation placard is for referenceduring manual operations.

A toggle switch is for control of theoutflow valve during manualoperations.

A dual-needle indicator shows thisdata:

• Cabin altitude (short needle)• Differential pressure (long

needle).

A cabin rate of climb indicator showsthis data:

• Rate of cabin ascent• Rate of cabin descent.

The push-button altitude horn cutoutswitch stops the 10,000 ft warninghorn.

System indication and warning lightsgive these indications:

• Automatic control channel failure• Aborted takeoff pressure

scheduling if the airplane is offthe scheduled descent

• Alternate channel automaticcontrol of the outflow valve

• Manual control mode of theoutflow valve.




FL260 FL320 FL410

800060004000

FL220

LAND ALTCAB ALT 2000

<FL160FLT ALT

EVLAV

MANUALAUTO

FLT ALT

ALTNMAN

ES

LC

NEP

AUTO

OO

LAND ALT

DESCENT

PRESS DIFFLIMIT: TAKE-OFF & LDG

.125 PSI

CUTOUTHORNALT

0

6

7

8

9ALT

CABIN2

3

4

5

10 1

1

21.5

.5

3

3

2

40

050

5

10

20

25

30

15

35

40

X 1000 FEET

DN

UP

ga gaFAIL

AUTO OFF SCHEDMANUALALTN

Fire Protection

November 2000 17-1

• Engine Fire Protection

• APU Fire Protection

• Wheel Well Fire and Duct LeakOverheat Protection

• Lavatory Fire Protection

• Portable Fire Protection

• Cargo Fire Protection

Features

ENGINE FIRE PROTECTION

The airplane structure uses firewallsand fireproof hardware in the firezones.

A dual loop engine fire detectionsystem gives high reliability and faulttolerance.

The fire protection module has BITE.

The identical components on theright and left engines reduce sparesinventory.

The fire protection controls are easilyoperated by either pilot.

There are two fire bottles toextinguish engine fires.

The engine fire bottles use HALONas the extinguishing agent.

APU FIRE PROTECTION

The APU torque box is fire-hardenedwith titanium plates. This replacesthe APU fire shroud and makes APUaccess better.

The APU fire detection elements areon the firewall structure. Thisdecreases the APU buildup.

The APU fire detection system hasautomatic APU shutdown.


APU fire protection panels are in theflight compartment and in the wheelwell. These panels give easy accessfor both flight crew and ground crew.

The APU fire bottle uses HALON asthe extinguishing agent.

WHEEL WELL AND DUCT LEAKFIRE PROTECTION

The overheat module has BITE.

The system detection loops simplifytroubleshooting and maintenancerequirements.

LAVATORY FIRE PROTECTION

Airplane lavatories have modularsmoke detectors.

Airplane lavatories have automaticfire extinguisher bottles in the wastebins.

PORTABLE FIRE PROTECTION

The flight compartment and galleyshave portable fire extinguishers.

HALON BFC

Airplane fire extinguishers useHALON.

CARGO FIRE PROTECTION

The cargo compartments havesmoke detectors and fire bottles.

The smoke detectors give warning tothe flight crew if there is smoke in acargo compartment.

The cargo smoke detection and firesuppression module is on the P8panel. The panel gives both pilotseasy access to the controls andindications.

One cargo electronic unit is in theceiling of each cargo compartmentinboard of the cargo door. The cargoelectronic unit monitors the cargocompartment fire detectors and hasBITE.

The cargo compartment fire bottlesuse HALON as the fire extinguishingagent.

17-2 November 2000

Engine Fire Protection

STRUCTURE AND MATERIALS

These features protect the airplanestructure from fire:

• A vapor-tight, insulated,stainless-steel firewall isolatesthe engine from the wing

• The upper areas of the enginecowls have fire shielding

• Fire and fluid leakage zones havedrains to prevent the collection offlammable fluids

• Fire zone hoses and hardwareare fireproof.

ENGINE FIRE DETECTION

The engine fire detection systemuses dual-loop sensors for reliability.A single failure will not make thesystem inoperative.

Each detection loop has fourdetection elements in these areas:

• The engine fan (2)• The engine core (2).

The engine fire protection module inthe EE compartment monitors datafrom the detection loops. The modulecan tell the difference between theseconditions:

• Engine overheat• Engine fire• System faults.

Signals from the engine fireprotection module give theseindications and alarms to the flightcrew:

• Engine overheat• Engine fire• System faults.

Overheat alarms come before firealarms. Pilot response to thesealarms can prevent prematureengine shutdowns. Overheat

conditions unlock the engine fireswitches and give these indications:

• Master caution lights• Engine overheat light.

Higher engine temperatures will givean engine fire alarm. The fire alarmincludes the overheat caution andthese other indications:

• Master fire warning lights• Fire switch lights• Fire bell aural warning.

FEATURES

The engine fire protection modulenormally uses logic that requiresagreement of both detector loops foran alarm output. If one loop becomesinoperative, however, the module willuse only the operative loop fordetection and alarm output.



Overheat/ Fire Protection Panel (P8)

FAULT

TESTINOP

OVHT

FIRE

WHEELWELL

FAULT

APU DETINOP

DISCH

r

BELL CUTOUT

A

OVHT DET

B

NORMAL

OVERHEAT

a

A

L

OVHT DET

B

NORMAL

ENG 1OVERHEAT

aENG 2

L

r

DISCH

R

r

DISCH

R

a

APU BOTTLEDISCHARGED

a

DISCHARGEDDISCHARGEDL BOTTLE R BOTTLE

FIRE SWITCHES(FUEL SHUTOFF)

PULL WHEN ILLUMINATEDLOCK OVERRIDE: PRESSBUTTON UNDER HANDLE

ENGINES

EXT

TEST R

L

1 2

g

g

g

APU

a

a

a

r

Fire Detection Module

APU

A

FAULT DISPLAY

WIRING OPEN or DETECTOR(S) FAULT

WIRING SHORT TO GND

ENGINE

CORE RIGHTCORE LEFT

LOOP POWERLOW DET. RESISTANCE

CLEAN CONNECTIONS

FAN UPPERFAN LOWER

APUUPPERLOWER

BLOOP

ENGINE 1

ENGINE 2

FIRE & OVERHEAT DETECTION

FAULT AREA

IF ALL 8 LIGHTS ONTEST PASSES

HOLD 5 SECPRESS AND

FAULT / INOP TEST

SEE F.I.M. FORMULTIPLE FAULTS OR

FAULT CODE INFO.

7 3 7 - 6 0 0 / 7 0 0 / 8 0 0 ONLYDETECTOR FAULT FOR

A BLOOP

Loop B

Loop A

Sense Elements(Dual Loop)

Detector Signals

Alarm/Fault Fire DetectionModule

Fire Protection

November 2000 17-3


ENGINE FIRE EXTINGUISHING

You lift and turn the fire switch(handle) which has the light on theoverheat/fire protection panel tooperate the engine fire extinguishingsystem.

When you lift the fire switch, theseengine systems isolate or shut down:

• Engine fuel system• Engine hydraulic system• Engine electric power system• Engine pneumatic system• Engine thrust reverser system.

When you turn the fire switch, one oftwo fire bottles discharges to theengine extinguisher manifold. If youturn the switch left, the left bottledischarges. If you turn the switchright, the right bottle discharges.

There are two fire extinguisherbottles in the main wheel well. Eachbottle can discharge to either engine.The bottles use HALONextinguishing agent and have thesefeatures:

• Pressure gages• Dual element discharge

cartridges (squibs)• Discharge indication switches• Overpressure relief disks.

You replace the fire bottle forservicing.

CONTROLS AND INDICATION

The overheat/fire protection panel isbetween the two pilots. This givesaccess by either pilot.

Switches on the overheat/fireprotection panel control thesefunctions:

• System tests

• Engine detection loop selection• Fire warning bell cutout• Engine systems shutdown• Fire bottle discharge.

Lights on the overheat/fire protectionpanel and glareshield (P7) showthese indications:

• Fire detection system tests• Fire extinguisher system tests• Engine overheat conditions• Engine fire conditions• Fire bottle discharge• Fire protection system faults.

A placard on this panel gives fireswitch instructions.

Pressure gages and pressure reliefdisks on the fire bottles show bottlecondition.


Engine Fire Bottles (2)

Overheat/ Fire Protection Panel (P8)

FAULT

TESTINOP

OVHT

FIRE

WHEELWELL

FAULT

APU DETINOP

DISCH

r

BELL CUTOUT

A

OVHT DET

B

NORMAL

OVERHEAT

a

A

L

OVHT DET

B

NORMAL

ENG 1OVERHEAT

aENG 2

L

r

DISCH

R

r

DISCH

R

a


a




ENGINES

EXT

TEST R

L

1 2

g

g

g

APU

a

a

a

r

Fire DetectionModule

Alarm/Fault

ToEngine 2

ToEngine 1

Bottle Discharge

17-4 November 2000

APU Fire Protection

STRUCTURE AND MATERIALS

These structural features protect theempennage from fire:

• A titanium APU torque boxfirewall

• Drains to remove flammablefluids

• Fireproof fire zone hoses andhardware.

APU FIRE DETECTION

The APU fire detection system is asingle loop system. The loop has twosense elements on the APU torquebox firewall and one sense elementabove the tailpipe.

The engine fire protection modulemonitors the detection loop. Themodule is in the EE compartment. Itcan tell the difference between theseconditions:

• APU fire• System faults.

The APU fire detection system doesnot detect overheat conditions.

Signals from the fire protectionmodule gives these indications andalarms to the flight crew:

• APU fire• System faults.

High temperatures in the APUcompartment produce an APU firealarm. Fire alarms show in these twoplaces:

• The flight compartmentoverheat/fire protection panel(P8)

• The wheel well APU fireprotection panel (P28).

APU fire alarms cause thesefunctions:

• Automatic APU shutdown• The master fire warning lights

comes• The APU fire switch light on P8

comes on• The APU fire switch on P8

unlocks• The flight compartment fire bell

rings• The APU fire warning light on

P28 flashes• The APU fire warning horn on

P28 sounds (on the ground only).

FEATURES

Fire alarms automatically shutdownthe APU.


APU Fire Protection

Sense Elements

APU ElectronicControl Unit

Fire Detection Module

APU

A

FAULT DISPLAY

WIRING OPEN or DETECTOR(S) FAULTWIRING SHORT TO GND

ENGINE

CORE RIGHTCORE LEFT

LOOP POWERLOW DET. RESISTANCE CLEAN CONNECTIONS

FAN UPPERFAN LOWER

APUUPPERLOWER

BLOOP

ENGINE 1

ENGINE 2

FIRE & OVERHEAT DETECTION

FAULT AREA

IF ALL 8 LIGHTS ONTEST PASSES

HOLD 5 SECPRESS AND

FAULT / INOP TEST

SEE F.I.M. FORMULTIPLE FAULTS OR

FAULT CODE INFO.

7 3 7 - 6 0 0 / 7 0 0 / 8 0 0 ONLYDETECTOR FAULT FOR

A BLOOP

A. P. U.FIRE

CONTROL

R

APU Ground ProtectionPanel (P28)

Overheat/Fire Protection Panel (P8)

FAULT

TESTINOP

OVHT

FIRE

WHEELWELL

FAULT

APU DETINOP

DISCH

r

BELL CUTOUT

A

OVHT DET

B

NORMAL

OVERHEAT

a

A

L

OVHT DET

B

NORMAL

ENG 1OVERHEAT

aENG 2

L

r

DISCH

R

r

DISCH

R

a


a




ENGINES

EXT

TEST R

L

1 2

g

g

g

APU

a

a

a

r

DetectorSignal

APU Shutdown

Alarm

Fire Protection

November 2000 17-5

APU Fire Protection

APU FIRE EXTINGUISHING

APU fire extinguishing can be donefrom the flight compartment or fromthe wheel well.

In the flight compartment, when youlift the fire switch, these systemsshutdown:

• APU• APU fuel system• APU air systems• APU electric power system.

When you turn the fire switch, theAPU fire bottle discharges. There isonly one fire bottle available for theAPU. Turn the switch in eitherdirection to discharge the bottle.

The wheel well fire protection panelhas controls to extinguish an APUfire. Pull down on the handle toshutdown the APU systems and arm

the fire bottle discharge switch. Pushthe toggle switch to discharge theAPU fire bottle.

The APU fire bottle is behind the aftpressure bulkhead in section 48. Thebottle is filled with HALON and hasthese features:

• Discharge cartridge• Discharge indication switch• Overpressure relief disk.

You replace the APU fire bottle forservicing.


APU fire protection controls andindications are in the flightcompartment and the wheel well. Inthe flight deck, they are between thepilots on the overheat/fire protectionpanel (P8) and the glareshield (P7).In the wheel well, they are on theAPU ground protection panel (P28).

These locations give access to flightcrew and ground personnel.

Switches on the overheat/fireprotection panels control thesefunctions:

• System tests• Fire warning bell cutout• APU systems shutdown• APU fire bottle discharge.

Lights on the overheat/fire protectionpanels are for these indications andfunctions:

• Fire detection system tests• Fire extinguisher system tests• APU fire conditions• APU bottle discharge• Fire protection system faults.

A placard on the P8 panel gives fireswitch instructions.

APU Fire Protection

APU Fire Bottle

Overheat/Fire Protection Panel (P8)

FAULT

TESTINOP

OVHT

FIRE

WHEELWELL

FAULT

APU DETINOP

DISCH

r

BELL CUTOUT

A

OVHT DET

B

NORMAL

OVERHEAT

a

A

L

OVHT DET

B

NORMAL

ENG 1OVERHEAT

aENG 2

L

r

DISCH

R

r

DISCH

R

a


a




ENGINES

EXT

TEST R

L

1 2

g

g

g

APU

a

a

a

r

A. P. U.FIRE

CONTROL

R

APU Ground ProtectionPanel (P28)

AlarmFire DetectionModule

Bottle Discharge

17-6 November 2000

Wheel Well Fire and Duct LeakOverheat Protection

GENERAL

The detection elements (single loop)sense these conditions:

• Wheel well fire• Overheats caused by a

pneumatic duct leak.

The elements are in these areas:

• Main wheel well• Engine struts and wing leading

edges inboard of the struts• Air conditioning bays• APU duct areas.

The overheat accessory unitmonitors the detection loops. It is inthe EE compartment. The modulecan tell the difference between theseconditions:

• Overheat conditions• System faults.

Wheel well overheat conditionscause these indications:

• Master fire warning lights on P7• WHEEL WELL light on P8• Fire bell.

Duct leak overheat conditions causethese indications:

• Master caution lights on P7• WING-BODY OVERHEAT lights

on P5.

CONTROLS AND INDICATIONS

These are the wheel well fire controlsand indications:

• Toggle switch for system test onP8

• Master fire warning lights on P7• WHEEL WELL fire light on P8• Fire bell (P9 aural warning

module).

These are the duct overheat controlsand indications:

• Push-button switch for systemtest on P5

• Master caution lights on P7• WING-BODY OVERHEAT lights

on P5.

FEATURES

The overheat accessory unit hasthese features:

• BITE• Nonvolatile fault memory.

The overheat detection loopconfiguration makes troubleshootingeasy.

Wheel Well and Duct Leak Fire Protection

APU Duct LeakDetection Elements

Strut Detection Elements

Wheel Well

Pack Bay Detection Elements

Detection Element

Leading Edge

P7 Glareshield Lights

P5 Panel Lights

Overheat

P8 Panel Lights

Accessory Unit

Detection Elements

Fire Protection

November 2000 17-7

Lavatory Fire Protection

LAVATORY SMOKE DETECTION

Smoke detectors are in the ceilingsof all lavatories. The detectorsoperate a warning horn that is heardin the passenger cabin.

Lights on the detector show theseconditions:

• System power (green)• Alarm (red).

The smoke detectors are modular,simple, and reliable.

LAVATORY FIRE EXTINGUISHER

A fire extinguisher bottle is in thewaste bin of each lavatory.

The extinguisher has these features:

• Automatic discharge operation• HALON extinguishing agent.

Heat sensitive tape near the bottle isused for these reasons:

• Show bottle discharge• Record event temperature.

You replace the lavatory fire bottlefor servicing.

Portable Fire Protection

These are the two types of portablefire extinguishers:

• HALON• Water.

HALON fire extinguishers are in theflight compartment.

HALON and water fire extinguishersare in the galley areas.

These are the advantages ofHALON:

• The best fire extinguishingproperties

• HALON extinguishes solid andliquid combustibles or electricalfires.

• Chemically stable, long lifeproperties

• Noncorrosive properties• Nontoxic properties• Leaves no residue for reduced

clean-up requirements.

Lavatory Fire Protection

Lavatory Module

Smoke DetectorLavatory Fire

Alarm Indicator

Power Indicator

Alarm Horn

Paper

Lav Fire Extinguisher Bottle

Heat

(Green)

Cutout Switch (Red)

Extinguisher Bottle

SensitiveTape

Waste Bin

17-8 November 2000

Cargo Fire Protection

CARGO SMOKE DETECTION

The forward and aft cargocompartments have smoke detectorsin a dual loop configuration. Thesmoke detectors monitor the cargocompartment air for smoke.

A cargo electronic unit monitors thesmoke detectors.

If there is smoke in the cargocompartment, the cargo electronicunit causes a cargo fire warningalarm. The fire warning bell operatesand the fire lights come on. The FWDor AFT cargo fire warning light on thecargo smoke detection and firesuppression module comes on. Todischarge the fire bottle, push theforward or aft cargo fire arm switch,then push the guarded dischargeswitch.

SMOKE DETECTORS

On the 737-600/700, both theforward and aft cargo compartmentshave four smoke detectors. On the737-800, the forward cargocompartment has four smokedetectors and the aft cargocompartment has six smokedetectors. The forward and aftsmoke detectors are identical.

The smoke detectors have thesecomponents:

• One electrical connector• Four shock mounts• Smoke detection chamber

(internal)• Electronic unit.

The smoke detectors usephotoelectric cells to detect smoke.

CARGO ELECTRONIC UNITS

There is one cargo electronic unit inthe ceiling of each cargocompartment inboard of the cargodoor. The forward and aft cargoelectronic units are identical.

The cargo electronic unit has thesecomponents:

• Two electrical connectors• Two attachment brackets• 16 red light emitting diodes

(LEDs)• Lamp test switch• System test switch• Electronic circuit• Translucent fiberglass cover with

eight fasteners.

The cargo electronic unit has built-intest equipment (BITE). The BITEdoes power-up and periodic tests ofthe system. You can also use thesystem test switch to do a test of thesystem.


Smoke Detector (6)(-600 has 4)

Cargo ElectronicUnit

Cargo ElectronicUnit

Smoke Detector (4) Fire Bottle (1)(Option for 2)

Cargo Smoke Detectionand Fire Suppression Module

Fire Protection

November 2000 17-9

Main Deck Cargo Fire Protection

SMOKE DETECTION

The main deck cargo compartmenthas 14 cargo smoke detectors.There are six detectors in the forwardsection and eight detectors in the aftsection. The smoke detectors are inthe overhead areas. You lower theceiling panel to get access to thedetectors.

The cargo electronic unit for theforward main deck smoke detectorsis in the E9 equipment rack. Thecargo electronic unit for the aft maindeck smoke detectors is in the ceilingof the aft cargo compartment on theleft side near the aft cargo door.

CARGO FIRE PROTECTION

There are three cargo fire bottles thatcontain HALON fire extinguishingagent. Two of the bottles are alsoused for the lower compartment fire

extinguishing. The bottles are in theair conditioning distribution bay onthe left side of the aft bulkhead.

The bottles have the samecomponents as shown for the lowercargo compartment fire protection.

The discharge nozzle for the maindeck cargo compartments are in theceiling of the compartments.

Main Deck Cargo Fire Protection

Main Deck Cargo Compartment(Forward Shown, Aft Similar)

Forward Cargo Compartment(Looking Aft)

Aft Cargo Compartment(Looking Aft)

Forward CargoElectronic Unit (Ref)

Forward Main DeckCargo Electronic Unit

Aft Cargo ElectronicUnit and Aft Main DeckCargo Electronic Unit

DischargeNozzle (Typ)

Smoke Detector (Typ)

FWD

17-10 November 2000


CARGO FIRE CONTROL PANEL

The cargo fire control panel providescontrols and indications for the cargofire protection system. The panel ison the P8 panel and provides easyaccess for both pilots.

The cargo fire control panel hasthese functions:

• DETECTOR FAULT amber lightis on if one or more of thedetectors have a failure

• A three-position (A, NORM, B)DET SELECT SWITCH, one foreach cargo compartment. TheNORM position allows bothdetectors to give a fire alarm. Aor B allows selected detector tosense smoke and give fire alarm

• TEST push button switch does atest of the cargo smoke detectorsand the extinguisher system

• FWD, AFT red cargo fire warning

switch lights are on if there issmoke in the correspondingcargo compartment

• Guarded DISCH switch light ispushed to discharge fire bottlesand is used with the TEST pushbutton to do a test of the firebottle pressure switches

• FWD, AFT EXT lights show if firebottle squibs are good.

CARGO FIRE BOTTLE

The cargo fire bottle containsHALON fire extinguishing agent. Thebottle weighs approximately 33pounds (15 kg). The bottle is in theair conditioning distribution bay. It ison the left side of the aft bulkhead.An option is available to install twocargo fire bottles, one on the left andright side of the aft bulkhead.

The bottle has two dischargeassemblies (squibs) connected tothe discharge tubing. The discharge

tubing sends HALON to the forwardand aft cargo compartments.

The bottle has these components:

• Safety relief and fill port• Two handles• Pressure switch with test button• Three mounting brackets• Two discharge assemblies with

squibs.

The bottle provides HALON for 60minutes of fire suppression.


Smoke Detector

AFTFWD ARM

DET SELECT

ERIF

FWD

FWD

OGRAC

TEST

EXTAFT

AFT

ARMEDARMED

ANORM

BANORM

B

DISCH

DISCH

FAULTDETECTOR

Fire Extinguishing Bottle

that all A and B loop smoKe

INSTRUCTIONS:

respond by illuminating the corresponding indicator.

detectors and unused positions Properly functioning smoke

smoke detector. verify the function of each

2. Select PRESS TO TEST to detector indicators function

1. Select LAMP TEST to verify

functioning smoke detectors Until indicators represent non-

SENSITIVE ELECTRONIC DEVICEDO NOT OPEN EXCEPT ATAPPROVED HOLD FORCE

PROTECTIVE WORK STATION

Wilson, North Corolina 27896-9643 USADivision of KIDUE Technologies, Inc.

CAGE CODE 61423

TSO-C1C

FT

XX

/XX

CAUTION

WALTER KIDDE Aerospace

CARGO ELECTRONIC UNIT

PRESS DESIGN ACTIVITY/MFR61423MFD DATE:

SERNO:MKA PPC 473925

TO TEST

LAMPTEST

A

B

1 2 3 4 5 6 7 8

Cargo Electronic Unit

T

TSE

BBB AAA

ARMEDARMEDARMED

ARMARM

FAULTDETECTOR

DEPR/DISCH

DISCH

DEPR

AFTFWDMAIN

NORMNORMNORM

EXTSYS

ERIF

OGRAC

AFTFWDMAIN

DETECT SELECT

g g g

r r r

w ww

a

a

a

Cargo Fire Control Panel (P8)

Cargo Fire Control Panel (P8) (737-700C)

Ice and Rain Protection

November 2000 18-1

• Anti-Icing Systems

• Wing Anti-Icing

• Engine Anti-Icing

• Air Data Sensor Heat

• Window Heat

• Windshield Rain RemovalSystems

• Water and Waste System Heat

Features

GENERAL

The airplane has ice protection whichallows safe flight through icingconditions.

The system designs are simple.Components are chosen for highreliability.

The system controls, indications, andautomatic overheat protectionreduce crew work load.

WING THERMAL ANTI-ICE

Thermal anti-icing of the wingleading edge uses engine bleed air.

The wing thermal anti-icing systemoperates in flight and on the ground.

It is not necessary to have iceprotection for the empennagesurfaces.

ENGINE THERMAL ANTI-ICING

The inlet cowl of each engine uses itsown bleed air for anti-icing.

AIR DATA SENSOR HEAT

These air data sensors use electricalheat:

• Pitot probes• Alpha vane sensors• Total air temperature probes.

WINDOW HEAT

The windshields and sliding flightcompartment windows use electricalheat.

WINDSHIELD RAIN REMOVAL

A permanent coating on thewindshields repels water.

Windshield wipers improve visibilityfor takeoff, approach, and landing.

WATER SYSTEM HEAT

The water system servicing paneland drain masts are heatedelectrically in flight and on the groundto prevent freezing.

WASTE SYSTEM HEAT

The waste system servicing panelsand drain fittings have heat in flightand on the ground to preventfreezing.

18-2 November 2000

Anti-Icing Systems

THERMAL ANTI-ICING SYSTEMS

Engine bleed air prevents ice onthese surfaces:

• Outboard wing leading edges• Engine cowl inlets.

The pneumatic manifold supplies airto the first three leading edge slatsoutboard of the engine strut. Anti-icing can be done in any slat position.

Engine cowl anti-ice air is from eachengine bleed air manifold.

ELECTRIC SYSTEMS

These air data sensors use electricalheat:

• Pitot probes• Total air temperature probes• Alpha vanes.

The pitot probes have automaticpower reduction for groundoperations. This increases theoperational life of the probes.

The flight compartment windshieldsand sliding windows have electricalheat. Window heat for the fixed sidewindows is optional.

The drain masts use electrical heat.The drain masts have powerreduction for ground operations.

Electric heat for the water supplylines is optional.

The lavatory service panels anddrain fittings use electrical heat.

WINDSHIELD RAIN REMOVALSYSTEMS

The windshields have windshieldwipers. The windshields also have ahydrophobic coating of waterrepellent compound.

MISCELLANEOUS

The static pressure port heat is notnecessary.

There is no anti-icing for theempennage surfaces.

There is no anti-icing for the radome.

Conditioned air removes fog from thewindshields.

The multiple-pane construction of thepassenger windows keeps them freeof fog and frost.


Total Air Temperature (TAT) Probe

and IndicationsP5 Panel Controls

Rain Repellent)(Window Heat, Wipers,Flight Deck Windows

Pitot Probes (2 Each Side)

Elevator

Lavatory Service Panel

Wing ThermalSlat and Spray

Pitot Probes

Alpha Vane (Each Side)

Anti-Ice (WTAI)Tube (Typical)

WTAI Air Manifold

Drain Mast Heater (Typical)

Valve

Engine Cowl

(Each Side)Thermal Anti-Ice Valve


November 2000 18-3

Wing Thermal Anti-Icing

GENERAL

The wing thermal anti-ice (WTAI)system prevents ice on the wingleading edges.

Engine bleed air warms the wingleading edges. Wing thermal anti-icing valves control the flow of air tothe leading edges.

Hot air from the WTAI valve flowsthrough a leading edge supply ductto three telescopic feeder ducts.These ducts move the hot air tospray tubes inside the slat cavities.The spray tubes are perforated andsupply the hot air to the slat cavities.The hot air flows overboard throughholes in the lower surface of the slat.

WTAI ducts, valves, and overheatswitches are in the wing leadingedges.


A single switch on the P5 forwardoverhead panel controls the wingthermal anti-ice system. The switchcontrols both WTAI valves.

WTAI operates in flight or on theground. On the ground, the WTAIsystem closes the WTAI valves toprevent leading edge overheat andto reduce engine bleed loads duringtakeoff.

Two blue valve open lights show theposition or condition of the WTAIvalves. The lights are dim when theswitch is ON and valve is open. Thelights are bright when the valves arein transit or disagree with switchposition. The lights are off when theswitch is OFF and the valves close.

Wing Thermal Anti-Icing

Spray TubeSlat Extended

Slat Outer Skin

Slat Inner Skin

TelescopicFeeder Duct

A-ASlat Retracted

Spray

Slat

WTAI

Wing Thermal Anti-Ice

WTAI Overtemperature

SwivelConnection(Typical)

Tube

Cavity

Airflow

Anti-Ice Panel (P5)

A

A

(WTAI) Valve

Switch

ON

OFFWING ANTI-ICE

R VALVEOPEN

L VALVEb OPEN b

18-4 November 2000

Engine Thermal Anti-Icing

GENERAL

The engine inlet cowl anti-ice systemprevents ice on the cowl surfacesduring flight and ground operations.

The system uses air from the enginebleed air manifold. The air flows to acowl TAI valve. The valve controlsthe flow of the TAI air to the cowl. TAIair from the cowl TAI valve flowsthrough a duct to the hollow cowlinlet. TAI air circulates inside thehollow cowl. This warms the cowlinlet surface. The TAI air dumpsoverboard through an opening in thebottom of the cowl.

CONTROL AND INDICATION

The two engine inlet cowl anti-icesystems operate independently.

Switches on the P5 forwardoverhead panel control the cowl TAIvalves.

Two blue COWL VALVE OPENlights on the P5 panel show thecondition of the cowl TAI valves. Thelights are dim when the switch is ONand the valve is open. The lights arebright when valve position does notagree with switch position. The lightsare off when the switch is OFF andthe valves close.

Two amber COWL ANTI-ICE lightson the P5 panel show systemoverpressure conditions.

Engine Thermal Anti-Icing

TAIDuct

Precooler

PressureRegulating andShutoff Valve

9th-Stage

5th-Stage Bleed

High-Stage

Pressure Switch

TAI Valve

Engine Bleed Manifold

Bleed Manifold

P5 ForwardOverheadPanel

Anti-Ice Panel

Hollow Nose Cowl Cavity

TAI Overboard

ENGANTI-ICE

OFF

ON1 2

ANTI-ICECOWL

ANTI-ICECOWL

a

b

a

bOPENCOWL VALVE

OPENCOWL VALVE

Discharge

Valve


November 2000 18-5

Air Data Sensor Heat

GENERAL

Air data sensors have heat toprevent ice formation. This preventsthe erroneous indications of a sensorwith ice.

These sensors get heat from integralelectrical heaters:

• Pitot probes• Elevator feel pitot probes• Alpha vane sensors (angle of

attack sensors)• Total air temperature probe.

Heat for the static ports is notnecessary.

The pitot probes are on both sides ofthe forward fuselage.

The elevator feel pitot probes are onthe vertical stabilizer.

The relays and transformers thatsupply the voltage to the air dataprobes are in the EE compartment.


Two switches on the P5 forwardoverhead panel control the air dataprobe heat. The probe heat has twosystems, A and B.

Amber system warning lights showwhen a probe does not have heat.

Air Data Sensor Heat

Air Data Sensors

Elevator Pitot

• Pitot Probes• Alpha Vane Sensor• Total Air Temperature Sensor

Probe Heat Panel (P5)

PITOT STATICA

OFFB

ON

HEAT

CAPT PITOT

L ELEVPITOT

L ALPHAVANE

PROBETEMP

a

a

a

aF/O PITOT

AUX PITOT

R ELEVPITOT

R ALPHAVANE

a

a

a

a

18-6 November 2000

Window Heat

GENERAL

The windshields and sliding windowshave heat for these reasons:

• Prevent windshield icing• Increase windshield impact

strength.

The windshields and sliding windowsare made of multiple layers. Oneinternal layer is made of a clear,electrically conductive paste.

The application of electric power tothis conductive layer produces acurrent that warms the window.

These windows have heat:

• Windshields (1L and 1R)• Sliding windows (2L and 2R)• Eyebrow windows (4L, 5L, 4R,

and 5R).

Heat for side windows 3L and 3R isoptional.

Four window heat control units in theEE compartment control the heaterpower to the windshield and slidingwindows.

Thermal switches on the 5L and 5Rwindows control heater power to theeyebrow windows.

Conditioned air removes the fog fromthe windshields.

Passenger cabin windows keep freeof fog by their spaced, multiple paneconstruction.


These switches on the P5 forwardoverhead panel control the windowheat system:

• FWD switches apply power to thewindshields

• SIDE switches apply power to thesliding and eyebrow windows

• OVHT / PWR TEST switchcontrols overheat and powertests of the window heat system.

Four green ON lights show when thewindows are being heated.

Four amber OVERHEAT lights showa window overheat condition.Circuits in the control unit removepower from the overheated window.

FEATURES

The window heat control units haveBITE.

Window Heat

Window Heat Control Unit (4)

Thermal Switch (2)

No. 5 Eyebrow

DATE OF MFR.SERIAL NO.

CONTROL UNITWINDOW HEAT

Window

Probe Heat Panel (P5)

ONg

OVERHEATa

ONg

OVERHEATa

ONg

OVERHEATa

ONg

OVERHEATa

SIDE

ON

OFF

LFWD

WINDOW HEAT

PWR TEST

OVHTFWD

OFF

ON

SIDER


November 2000 18-7

Windshield Rain RemovalSystems

WINDSHIELD WIPERS

Two electric windshield wipers keepthe windshields clear of rain.

The windshield wiper motors are onthe lower windshield sill beam.

Two selectors or an optional singleselector on the P5 forward overheadpanel control the windshield wipermotors. The selectors have thesepositions:

• Park (0ff)• Intermittent• Low• High.

The wipers are self parking.

RAIN REPELLENT WINDSHIELDCOATING

A water repellent coating is on bothforward windshields.

The coating causes liquid droplets tobead-up and roll off the windshield.This makes visibility in heavy rain,better.

Windshield Rain Removal Systems

Windshield Wiper

P5 Panel

Wiper Motor

Controls

Assembly

OVERSPEEDFAULTMAINT

a aabPRESSURE

LOW OIL

PARKINT

LOW

HIGH

R WIPER

C X 100

8 EGT INT

LOW

HIGH

PARKL WIPER

60

4 2

10

Rain Removal Panel (P5)

18-8 November 2000

Water and Waste Systems Heat

POTABLE WATER SYSTEM

Electrical heating protects thepotable water service panel fromfreezing.

Potable water distribution line heat isoptional.

DRAIN MASTS

The water drain masts haveelectrical heaters. The heaters arebuilt into the masts.

LAVATORY SYSTEM

Electric heating protects the lavatorydrain valves and rinse fittings fromfreezing.


The airplane electrical systemsupplies ac power to the water andwaste system heaters.

Power to the drain masts decreaseson the ground. This feature hasthese advantages:

• Increases the operational life ofthe masts

• The masts do not get hot enoughto burn personnel on the ground.

System control is automatic. Thesystem has heat when the airplane'selectrical buses have power. Thereare no indications for these heaters.

Water and Waste Systems Heat

Aft Drain Mast

Forward Drain Mast

Lavatory Service Panel

Potable WaterService Panel

Cabin Systems

November 2000 19-1

• Flight Crew Oxygen

• Passenger Oxygen

• Passenger CompartmentEquipment and Furnishings

• Potable and Gray Water

• Lavatory Waste Systems

Features

OXYGEN SYSTEMS

Flight crew oxygen is a gaseoussystem.

The passenger oxygen system useschemical generators to supplyoxygen. The passenger oxygensystem has automatic deployment.

PASSENGER COMPARTMENTEQUIPMENT AND FURNISHINGS

The airplane features hightechnology interiors.

High technology interiors increasepassenger comfort, convenience andsafety.

High technology interiors are easy tomaintain.

Modular galley and lavatory unitsincrease configuration flexibility.

POTABLE AND GRAY WATER

The potable water system has 40 or60 gallon water tanks available.

All system components are madefrom corrosion resistant materials.

Super chlorinated solutions are usedfor sterilization of the water system.

The water system supply lines willnot break or permanently distort ifthey freeze.

The potable water system servicepanel is easy to access. It usesstandard service fittings.

Gray water from the galleys andlavatory wash basins drainsoverboard through heated drainmasts. Gray water holding tanks areoptional.

LAVATORY WASTE SYSTEMS

The modular lavatory units increaseconfiguration flexibility.

Standard lavatory modules have avacuum flush system.

The lavatory system service panel iseasy to access. It uses standardfittings.

19-2 November 2000

Flight Crew Oxygen

GENERAL

The flight crew oxygen system hashigh pressure oxygen gas.

Oxygen is stored in a cylinder in theEE compartment. The cylinder isaccessed from the forward cargocompartment.

The cylinder is protected fromoverpressure by an overboard reliefport.

A regulator on the cylinder reducesthe oxygen pressure.

The oxygen supply line and manifoldis made of seamless stainless steeltubing.

Modular mask units supply theoxygen to the flight crew stations.


A gage on the aft P5 panel showsoxygen cylinder pressure.

A gage on the cylinder also showsbottle pressure.

A green disk, on the airplane skin,covers the bottle overboard pressurerelief port. When the disk is broken, itshows that cylinder overpressurecaused overboard relief.

Automatic valves and flow regulatorsin the mask modules supply flow tothe user when the mask is put on.

A mask module flow indicator showsoxygen flow to the user.

FEATURES

Modular masks have these features:

• Diluted or 100% oxygen flow• Demand or continuous flow• Goggle smoke clearance• Integral microphones• Quick, one-handed operation• High reliability• Easy serviceability• Reduced spares inventory.

You service the oxygen cylinder byremoval and replacement. Anexternal oxygen service panel isoptional.

Flight Crew Oxygen

Aft Overhead Panel (P5)

Oxygen Mask

Oxygen Mask

Oxygen MaskModule (Typical)Discharge

Indication Disk Module

OxygenCylinder

CREWOXYGEN

OXY.PRESS.

10

5

PSI X 100

15

200

Cabin Systems

November 2000 19-3

Passenger Oxygen

Chemical oxygen generators supplyemergency oxygen to thepassengers and flight attendants.

The generators are in these areas:

• Passenger service units (PSUs)• Attendant service units (ASUs)• Lavatory service units (LSUs).

Oxygen masks deploy automaticallyor manually.

Electrical release of a spring-loadeddoor in the service unit deploys themasks. The open door drops theoxygen masks. A short tetherconnects the masks to the generatoractivation pin. You pull the mask toactivate the oxygen generator. Aflexible tube supplies oxygen to themask.

The generators supply oxygen at arate and for a duration, sufficient forpassenger safety during descent (15minutes).

You service the oxygen generatorsby removal and replacement.

In addition to the PSU oxygengenerators, portable gaseousoxygen cylinders are available foremergency first aid. These cylindersare near the flight attendant stations.


The oxygen masks are deployed ineither of two ways:

• Automatically by an aneroidpressure switch in the EEcompartment. This occurs at acabin pressure altitude of 14,000feet

• Manually by a guarded toggleswitch on the P5 aft overheadpanel.

An amber light on the aft P5 panelshows when the oxygen masksdeploy.

Tape on the oxygen generators showthe condition of the generators.

FEATURES

There are extra oxygen masks ateach PSU for infants.

Test latches in the service unitsmake maintenance and system testseasier.

Passenger Oxygen - Chemical

Oxygen Mask(Typical)

Oxygen

Oxygen

Side View Of PSU

Release

Generator

Mechanism

Mask

PASS OXYGEN

PASS OXYON

NORMAL

ON

a


19-4 November 2000

Gaseous Oxygen System

This gaseous oxygen systemsupplies oxygen to these areas:

• Passenger service units• Aft attendant service unit• Aft lavatory service unit.

The features and operation of theservice units is the same as thechemical oxygen system.

OXYGEN CYLINDERS

There are two high pressure oxygencylinders in the aft cargocompartment.

FORWARD GALLEY ANDLAVATORIES

The forward galley and lavatoriesuse chemical oxygen generatorsbecause the distribution of gaseouspassenger oxygen does not goforward of the passenger area.

Passenger Oxygen - Gaseous (Optional)

CARGO PASSENGER

CABIN CONFIGURATION TEST CREW/PASS OXYGENPASS

RESET

NORM

ONCREW

IND SELPASS

PASS OXYON

OXY.PRESS.

10

5

PSI X 100

15

20

aPassenger Service Unit

Cabin Configuration Test Panel (P5)

Oxygen Control Panel (P5)

Oxygen Cylinder Assembly

Cabin Systems

November 2000 19-5

Passenger CompartmentEquipment and Furnishings

HIGH TECHNOLOGY INTERIORS

Interior panels are made of tough,lightweight composite materials thathave these features:

• An aesthetic look and feel• Easy clean-up• Easy service accessibility.

Large overhead stowage bins supplyspace for carry-on items. Bin doorslatch to keep objects from falling onpassengers.

Passenger service units (PSUs)include these items:

• Passenger signs• Passenger address speakers• Oxygen generators• Cabin attendant call buttons• Reading lights• Individual gasper air outlets• Simplified service and access

• Easy adjustment for flexible classconfigurations.

SEATING

Passenger seats mount into tracks inthe floor. The seats give passengerscomfort and safety. The seat pitch iseasy to change.

GALLEYS AND LAVATORIES

Modular galleys and lavatoriesincrease cabin configurationflexibility.

WINDOWS

Passenger windows have dual-panefail-safe structures. An additionalnon-structural interior reveal paneprevents window fog and frost.

EMERGENCY EQUIPMENT

Equipment installed for emergencyegress include these features:

• Automatic emergency escapelights

• Automatic door mounted escapeslides (slides double as life rafts)

• Overwing escape hatches• Ceiling mounted life raft stowage

bins (optional).

CONTROLS AND INDICATIONS

Ground service bus controls andpassenger compartment lightingcontrols are on the flight attendantspanels.

Ground service bus powerreceptacles are near the servicedoors. The receptacles are aconvenient source of power forcleaning crews.

Passenger Compartment Equipment and Furnishings

Air Return Grille

Passenger Service Unit (PSU)

Passenger Window

Bullnose Panel

Ceiling Panel

Overhead Stowage Bin

Handrail (Optional)

Track Mounted Seating

Seat Track

Emergency Escape Hatch

Sidewall Panel

19-6 November 2000

Potable Water System

GENERAL

Potable (drinkable) water is stored ina single tank under the cabin floor.The tank is aft of the aft cargocompartment. The tank supplieswater to these areas:

• Galleys• Lavatory wash basins• Vacuum lavatory toilet rinse.

Air pressure in the water tank forceswater through the potable watersystem plumbing. Pressurized aircomes from these sources:

• APU bleed air duct• Electric compressor.

The tank is protected from collapse,contamination, andoverpressurization. This is done by apressure regulator, filter, relief valve,and venting.

A quantity transmitter on the tanktransmits water tank quantity to aliquid crystal display (LCD) gage onthe aft attendant panel.

Water system servicing is from apanel below and aft of the aft servicedoor.

The water system plumbing is madeof corrosion-resistant tubes andhoses. The components have thesefeatures:

• Sustain a freeze without ruptureor permanent set

• Be compatible with superchlorinated solutions (for systemsterilization)

• Increase the flexibility of galleyarrangements.

The lavatory wash basins have thesefeatures:

• Electric water heaters• Service shutoff and drain valves

• Self-venting faucets• Charcoal filters (optional).

Gray water (waste water) drainsthrough electrically heated drainmasts. Gray water holding tanks areoptional.

FEATURES

Drain valves and self venting faucetssimplify system draining.

The service panel uses standardfittings.

Insulated blankets prevent the watertank from freezing.

Additional ribbon, blanket, and fittingheaters are available for operation incolder climates.

The system complies with U.S.Public Health Services (USPHS)regulations.

Water System

T

HH

PressureSupply(Ref)

CabinFloor

Water

(Typical)Aft Lavatory Aft Galley

(Typical)Lavatory(Typical)

ForwardGalley

(Typical)WaterHeater

Water QuantityIndication

FillFittingDrain

MastServicePanel

Aft DrainFitting

Aft DrainMastDrain

Fitting

Fill/Overflow Valve

Water TankWaterTank DrainValve

Forward LavatoryDrain Valve

Water SupplyShutoff Valve

Water QuantityTransmitter

ToiletRinseValve

AirCompressor

Forward

ForwardForward

Cabin Systems

November 2000 19-7

Lavatory Waste Systems

GENERAL

Lavatories have these features:

• Toilet• Wash basin with hot and cold

water taps• Mirror• Lights• An attendant call button• Passenger service unit• Smoke detector• Trash bin with automatic fire

extinguisher.

There are fluorescent lights in thelavatories. When the lavatory doorlocks, the lights become brighter.

The lavatory modules can install indifferent positions. Customerrequirements determine the position.

VACUUM TOILETS

The standard lavatories use avacuum waste system.

The vacuum waste system usesseveral lavatory modules connectedto one waste tank.


You can monitor and test the vacuumwaste system from the aft attendantpanel and the exterior service panel.

Push-button light-switches, and anLCD display show tank level andsystem faults.

Manual shutoff valves in thelavatories prevent the use of aninoperative lavatory module.

A logic control module (LCM)monitors and controls the system.

Lavatory Waste Systems

Lavatory Module

TESTPRESS TO

CLEAN/CHECKSENSOR

4

1/4

1/2

3/4

F

aINOPLAVS

WASTE SYSTEM

Aft Attendant Panel Center

19-8 November 2000

Vacuum Lavatory Waste System

GENERAL

The vacuum waste system designpermits single point servicing andlavatory installation in differentlocations.

The system uses differentialpressure (vacuum) to pull waste fromthe toilet to the holding tank. Avacuum blower supplies the requireddifferential pressure when theairplane is below 16,000 ft. Ambient-to-cabin differential pressuresupplies the vacuum when theairplane is above 16,000 ft.

A tank in the aft cargo compartmentholds the waste.

The system includes thesecomponents:

• Lavatory toilet modules• A waste collection and storage

system.

OPERATION

A flush switch starts the flush cycle.The flush cycle has this sequence:

• Below 16,000 ft, the vacuumblower operates

• The toilet rinse valve opensmomentarily to rinse the bowl

• The flush valve opensmomentarily to flush the bowl

• The flush circuit resets itself.

Automatic circuits prevents a flushcycle if these conditions occur:

• The holding tank is full• The waste collection system

does not operate• The storage tank drain valve is

open.

VACUUM WASTE SERVICE

The system has single sourceservicing. The service panel is on theaft lower left fuselage. For toiletservicing, these procedures arenecessary:

• Drain the storage tank• Rinse the storage tank.

Vacuum Lavatory Waste System

Toilet Service Panel

Flapper

Open

Drain Cap

Drain Valve

Drain Fitting

Rinse Fitting

Handle

Lever

Valve

Vacuum Waste System

PUSH PUSH

Vacuum ToiletAssembly (Typical)

Vacuum BlowerAnd Filter

Vacuum CheckValve

Liquid Separator

Waste DrainBall Valve

Waste Tank RinseFitting Assembly

Waste TankRinse Filter

Waste TankRinse Nozzle

Waste DrainValve Assembly

(Typical)

Waste Tank

Flush Switch(Typical)

And Pull Rod

Waste ServicePanel (Ref)

Waste DrainBlockageRemoval Valve

(Typical)

Lights

November 2000 20-1

• Flight Compartment Lights

• Exterior Lights

• Interior Lights

• Emergency Lights

Features

FLIGHT COMPARTMENT LIGHTS

All instrument panels have integrallights. Background lights, floodlights,dome lights and map lights alsosupply light in the flight compartment.

Chart lights point light to the captainand first officer sidewalls.

EXTERIOR LIGHTS

Landing lights let the flight crew seethe runway at night. Anti-collisionlights and position lights show theairplane to flight crews in otherairplanes. Logo lights show theairline logo to passengers in theairport terminal.

High-intensity strobe beacon lightsare on the top and bottom of thefuselage, aft of the wing leadingedge. Additional strobes are at eachwing tip and in the tailcone.

PASSENGER COMPARTMENTLIGHTS

Lights on top of the overhead storagebins, ceiling panels, and windowpanels provide light in the passengercompartment. Some ceiling panelshave night lights for low-levellighting.

SERVICE AND CARGO LIGHTS

There are lights in all of the serviceand cargo compartments for theground crew.

EMERGENCY LIGHTS

Emergency lights show the escaperoutes for passengers and crew.

20-2 November 2000

Flight Compartment Lights

Dome lights supply light for the flightcompartment. The light-shieldsupplies background light for themain instrument panels. Eachinstrument and instrument panel hasits own internal light. An overheadfloodlight points light on the controlstand. Flood lights point light at thecircuit breaker panels in the aftsection of the flight compartment.

MAIN PANEL LIGHTS

The instrument and main panel lightshave adjustable controls, identifiedas PANEL. These controls are on thelower part of the captain and firstofficer main instrument panels. Thecaptain PANEL control adjusts lightintensity on the captain main panel,the center panel and the glareshield.The first officer PANEL controladjusts light intensity on the firstofficer panel.

White floodlights are under theglareshield to supply light to the mainpanels. One control adjusts theintensity of these lights. It is on thelower part of the captain main paneland is identified as BACKGROUND.

The standby electrical systemsupplies power for the lights undersome conditions.

Floodlights are above the digital flightcontrol system (DFCS) mode controlpanel. One control adjusts theintensity of these lights. It is on thelower part of the captain main paneland identified as AFCS FLOOD.

Use the LIGHTS switch to adjust ordo as test of the flight compartmentindication lights. The switch is on thecenter instrument panel. Put theswitch in the BRT position and theindication lights come on bright. Putthe switch in the DIM position and thelights will be dim. Put the switch in

the TEST position and all of theindication lights come on bright.

The standby compass has aninternal light and a three-positionlight switch. The three positions areBRIGHT, DIM, and OFF.

CONTROL STAND LIGHTS

The control stand has lights insidethe instrument panel, like the units onthe main instrument panels. There isalso a white floodlight on the P5forward overhead panel whichsupplies light to the thrust leverquadrant on the control stand.Adjustable intensity controls forthese lights are on the control stand.These controls are identified asPANEL and FLOOD.

BRTLOWER DU

BRTUPPER DU

BRTINBD DU

BRT

MAIN PANEL

OUTBD DUOFF

Flight Compartment Lights - Forward Section

DOME WHITE

SwitchLight AndCompassStandby

Dome Light Switch

AFDS FLOOD

Panel Light Switch

LightPanelOverhead

Panel Light Switch

SwitchFloodlight

SwitchPanel Light

Master Test and

PANELFLOOD

OFF

DIM

BRIGHT

OFFOFF

OFF

OFF

OFF

OFF

PANEL

CIRCUIT BREAKER

PANEL

Dimming Switch

AFDS FloodlightSwitch

ControlStandFloodlight

CircuitBreakerPanelFloodlightSwitch

LIGHTS

BRT

TEST

DIM

Switch

Lights

November 2000 20-3

Overhead Panel Lights

An adjustable intensity controladjusts internal instrument lights andinstrument panel lights on theoverhead panels. It is on the forwardoverhead panel and identified asPANEL.

MAP LIGHTS

Map lights, which point lightdownward are above each pilot seat.Adjustable intensity controls forthese lights are identified as MAP.They are on the sidewall by eachpilot seat.

CHART LIGHTS

Chart lights, which point light on thesidewall panels are above each pilotseat. Adjustable intensity controls forthe chart lights are on each pilotsidewall.

UTILITY LIGHTS

Utility or flight kit lights are on thesidewalls. Each light has its ownadjustable intensity control. Thelights are attached to a flexible cordso that they can be pointed wherenecessary.

CIRCUIT BREAKER PANELLIGHTS

White floodlights supply light to thecircuit breaker panels behind thepilots. The floodlights are in the floor,sidewall, and overhead. Anadjustable intensity control for theselights is identified CIRCUITBREAKER. It is on the forwardoverhead panel.

DOME LIGHTS

Two white dome lights supply light tothe flight compartment. One domelight is on the panel behind eachpilot. A switch on the aft overheadpanel controls these lights. DOMEWHITE identifies this switch. Thisswitch has bright, dim, and offpositions. A separate lamp is in theleft dome light and part of theemergency light system.

OBSERVER LIGHT

Detachable observer reading lightsare on the circuit breaker panelsbehind the crew.

Aft Section

Flight Compartment Lights

MAP

Detail A

Utility LightWith Switch

Captain Sidewall First Officer Sidewall

Circuit BreakerPanel Floodlight


Map and ChartLight Switches

Circuit BreakerPanel

First ObserverReading LightWith Control

Circuit

Dome Light

See

Map Light Map Light

BreakerPanel

Utility Light

Second ObserverReading LightWith Control

Chart LightChart Light

CHART



Utility Light

Detail ASeeDetail A


OFFOFF

20-4 November 2000

Exterior Lights

Exterior light installations are reliableand easy to maintain. Double wing-tip position lights improve dispatchreliability. Exterior light switches areon the forward P5 overhead panel inthe flight compartment.

LANDING LIGHTS

There are two fixed and tworetractable landing lights. Fixedlanding lights are in the wing leadingedges near the fuselage. Retractablelanding lights are in the wing-to-bodyfairing. When the retractable landinglights extend, the lights point forward,parallel to the waterline of theairplane. The lights supply visibility atnight and in bad weather conditions.They decrease the effect of reflectedlight into the flight compartment.

POSITION LIGHTS

Position light modules are on theoutboard tip of each wing. Two lightsare in each module. The lights on theleft wing are red. The lights on theright wing are green.

Dual bulb white tail lights are on eachwing trailing edge near the wingtips.The lights point aft.

ANTI-COLLISION LIGHTS

Anti-collision lights are on the topand bottom of the fuselage, aft of thewing leading edge. Each anti-collision light is a strobe light with ared lens. Access to the upper light isthrough a passenger cabin ceilingpanel. You reach the lower light fromoutside the airplane.

LOGO LIGHTS

Logo lights are in the top of eachhorizontal stabilizer surface to supplylight to both sides of the verticalstabilizer.

WING AND TAIL STROBE LIGHTS

White strobe lights are in eachwingtip and on the tailcone.

RUNWAY TURNOFF AND TAXILIGHTS

Runway turnoff lights are in eachwing root. They point ahead and tothe side of the airplane to show thetaxiway turnoffs. A nose gear taxilight is on the inner cylinder of thenose gear shock strut. This lightturns with the nose gear.

Exterior Lights

Logo Light

Red Wingtip Position

Green Wingtip PositionWhite Tail Position

(Upper and Lower)

Logo Light

White Tail Position

Runway Turnoff

Nose Gear Taxi

Wing Illumination

Wing Illumination

White Anticollision Light


Red Anticollision

Landing (Wing to Body Fairing)

Runway Turnoffand Landing

Landing (Wing-to-Body Fairing)

and Landing


(Bottom)

Lights

November 2000 20-5

Wing Illumination Lights

Two halogen wing lights supply lightto the surface of the wings. The flightcrew can select the wing lights inflight to see the wing surface. Thelights are on each side of thefuselage. They are forward of thewing, above floor level.

SERVICE LIGHTS

Service lights are in the forwardlower service compartment and theaccessory compartment. Forwardand aft cargo compartment lights gooff when the cargo doors close.

Service lights are also in each wheelwell. These lights supply light to thenose and main gear compartmentsduring ground servicing. Switches forthese lights are in the flightcompartment, the main wheel wells,and right side of the fuselage nearthe nose.

Exterior Light Controls

RETRACT OFF POSITIONSTROBEWINGLOGO

OFFOFFOFF

ONONONON

EXTEN

ON ONON

OFF

RUNWAYTURNOFF

LANDING

FIXED

L R L R

TAXI

D

OFF

RETRACTABLE

P5 ForwardOverhead

Panel

ON

ANTICOLLISION

OFF OFF

ON

WELLWHEEL

ON

OFFL R

ILLUM SCAN

20-6 November 2000

Emergency Lights

INTERIOR

The emergency lighting systemsupplies light to the passengercompartment and flight compartmentwhen there is a power failure.

When there is a power failure,emergency lights come on. Specialbatteries supply power for theselights. Emergency lights are in theseareas:

• Exit locator signs• Overwing escape hatches• Flight compartment dome.

Control of these lights is manual fromthe P5 overhead panel or the aftattendant panel.

EXTERIOR

Exterior lights supply light for eachemergency escape egress area.They are on the fuselage skin inthese areas:

• Forward and aft entry doors• Forward and aft service doors• Overwing escape hatches.

Emergency Lights

Exit Indicator

Slide Light

Dome Light

Over Door Sign

Over WingEscape Lights

Over Wing HatchAisle Indicator

Exit Indicator

Exit Locator

Battery Pack

Battery Pack Assembly

Battery Pack Assembly

(Typical)

(Typical)

Assembly (Typical)

Airplane Access

November 2000 21-1

• Forward Airstair

• Exterior Doors

Features

FORWARD AIRSTAIR

A self contained forward airstair isoptional on the 737. The airstairgives airport terminal self-sufficiency.No ground support equipment isnecessary for passenger boarding.

EXTERIOR DOORS

These exterior doors give access toall compartments and service areas:

• Passenger entry doors• Service doors• Cargo doors• Compartment doors.

EMERGENCY EGRESS/RESCUE

Emergency exit doors add to theemergency escape and rescuepaths.

Flight compartment windows slideopen to give emergency escape andrescue paths. Rescue personnel canopen the first officer (F/O) windowfrom outside.

21-2 November 2000

Forward Airstair

GENERAL

A self contained forward airstair isoptional on the 737. The airstairallows the airplane to operate atairports with no ground supportequipment. The airstairs are keptunder the floor of the forward entrydoor.

These are the airstair majorcomponents:

• Airstair door• Airstair rails• Carriage• Upper and lower ladders• Upper and lower handrails• Airstair control relays• Airstair drive motors and drive

gearing• Airstair controls.

All airstair components are in the EEcompartment except the controls.The interior controls are on theforward attendant panel. The exteriorcontrols are on the exterior fuselagejust aft of the airstair door.

OPERATION

The airstair has electrical drive. It canextend in two different modes:

• Normal mode• Standby mode.

The airstair extension occurs in thissequence:

• Airstair door unlocks and opens• Airstair extends from the airplane

(folded)• Airstair ladders and handrails

unfold• Airstairs touch the ground and

fully extend• Power is automatically removed

from the drive motors• Upper handrails manually extend

and attach to the inside of theforward entry door.

The retraction process is the reverseorder of the extension.

Do these items before operation ofthe airstair to prevent damage toequipment and injury to personnel:

• Make sure the area outside theforward entry door is clear

• Do not extend or retract theairstair in winds of more than 40knots or in jet blast

• Stow and secure the upperhandrails before operation of theairstairs

• Do not walk on the airstair until itcompletely extends.


Simple controls and indicationreduce crew work load.

The airstair operation sequences areautomatic. The extension andretraction sequences use power,except for the manual extension andstowage of the upper handrails.

Control circuits prevent retraction ofthe airstair when the upper handrailsare not properly stowed.

The airstair operates from interior orexterior controls.

The interior controls have thesefeatures:

• Airstair tread lights switch• Guarded push-button switches

for extend and retract operations• Standby operation push-button

switch• Stairs operating light.

These conditions permit theoperation of the airstair from theinterior control panel:

• Forward entry door must be open• AC and DC power available.

The exterior controls have thesefeatures:

• Control handle with push-buttonrelease

• Mode selection toggle switch.

FEATURES

There are tread lights on the stairriser panels.

The airstair operates from theairplane battery for these modes:

• Exterior control• Standby mode.

Mechanical and electrical interlocksprevent accidental deployment.

When the upper handrails stow, theforward entry door can close with theairstair in the extend position.

The airstair can extend and retractmanually if the airstair drive systemfails.

The forward entry door gives entryand exit with passenger jetways orportable stairs without airstairextension.

Airplane Access

November 2000 21-3

AirstairLower

Upper

Carriage

DoorLadder

Ladder

Forward Airstair Door Opened Forward Airstair Extending and Unfolding

Forward Airstair

Airstair TreadLights Switch

Normal/StandbyMode Select Switch

Control Handle InReleased Position

Handle ReleaseButton

Interior Controls

Exterior Controls

Upper

LowerHandrail

Handrail

FORWARD AIRSTAIR

OFF

ON

AUTO

LIGHTS

RETRACT EXTEND

STANDBY

Retract/ExtendSwitches

Stairs OperatingLight

StandbyOperationSwitch

a

STAIRSOPERATING

(Forward Attendant Pane)l

Forward Airstair Fully Extended

21-4 November 2000

Exterior Doors

GENERAL

The doors are part of the airplaneprimary structure. The plug-typedoors take cabin pressure loads.Latch mechanisms hold the doorsclosed during unpressurizedoperations. Door pressure pinstransmit pressure loads to pads onthe door frame during pressurizedoperations. No new materials or toolsare necessary for door maintenance.

Exterior handles align with thefuselage to decrease drag.

The doors operate manually. Thelarger doors have spring-loadedcounterbalance mechanisms. Thesedecrease the force necessary toopen the doors.

ENTRY AND SERVICE DOORS

The entry and service doors openoutward. These are their features:

• Lock mechanism on the upperhinge holds the door open in highwind conditions

• Windows with orange escapeslide warning pennants

• Escape slides for emergencyexit.

Make sure the automatic slide is notarmed before you open the entry orservice doors. This prevents injury topersonnel and damage toequipment. When the slides arearmed, the orange warning pennantis put across the door window.

EMERGENCY ESCAPE/RESCUE

Emergency exit doors supplyadditional exits for the passengers ifthere is an emergency. The doorsopen outward when the interiorhandle or exterior vent panel are

operated. Opening is by twocounterbalance actuators and onehydraulic snubber.

The flight compartment slidingwindows supply emergency exitpaths. The first officer window has anexterior release for rescueoperations.

CARGO DOORS

The forward and aft cargo doorsopen inward. They have spring-loaded counterbalance mechanismsand over-center uplocks for easyoperation.

The main deck cargo door (MDCD) isnot a plug type door. It opensoutward and up with two positions,canopy and full open. It is electricallycontrolled and hydraulicallyoperated. If electrical or hydraulicpower is not available, a hand pumpcan be used to operate the door.

Exterior Doors

Aft Entry

Emergency Exit Door

Forward

Airstair Door

Aft Galley

Aft Cargo Door

Electronic Equipment Forward

GalleyService Door

Flight Compartment

(4 on 737-800/900)

Service Door

Forward Cargo Door

AccessDoor

Compartment DoorSliding Window

Entry Door

(Optional)

Door

48 SectionAccess Door Forward

Main DeckCargo Door(737-700C)

Airplane Access

November 2000 21-5

Exterior Doors

EE COMPARTMENT DOOR

The EE compartment door slidesopen. When it is open, it does notobstruct the EE compartment.

FORWARD EQUIPMENTCOMPARTMENT DOOR

The forward equipment compartmentdoor opens inward. It has a spring-loaded uplock latch.

FORWARD AIRSTAIR DOOR

The forward airstair door opensinward. This door is motor-driven. Itopens and closes with the airstairextension and retraction sequence.

Door Warning Lights


Amber lights on the P5 forwardoverhead panel show if there is anunlocked door.

The door latch and lock mechanismsuse micro-switches or proximitysensors for the door warning system.

The EQUIP light is for the EEcompartment door and the forwardequipment compartment door.Access panels (such as the refuelingor water service panels) can beincluded in the EQUIP light circuit asan option.

The pilot sliding windows are not partof the door warning system.

Door Warning Lights

Door Warning Panel (737-800/900)


RIGHTOVERWING

aLEFT

OVERWING

a

AFTSERVICEa

FWDCARGO a

AFTCARGO a

FWDSERVICEa

AFTENTRY a

EQUIPa

ENTRYFWD

aSTAIRAIR

a

STAIRAIR

AFTENTRY

a a

a

RIGHT FWDOVERWINGaRIGHT AFTOVERWINGa

FWDSERVICEa

LEFT AFTOVERWING

LEFT FWDOVERWING

FWDENTRY a

AFTSERVICEa

FWDCARGO a

AFTCARGO a

a

EQUIPa

Door Warning Panel (737-600/700)

CARGOMAIN

a

737-700C


November 2000 1

A

AC, ac alternating current

ACARS aircraft communicationand reporting system

ACM air cycle machine

ACMS airplane conditionmonitoring system

ACP audio control panel

ADF automatic direction finder

ADIRU air data inertial referenceunit

ADM air data module

AOA angle of attack

AOV aft outflow valve

APB auxiliary power unitbreaker

APU auxiliary power unit

ARINC aeronautical radio,incorporated

A/T autothrottle

ATC air traffic control

B

BCF bromochlorodifluoro-methane

BITE built-in test equipment

BPCU bus protection controlunit

BSV burner staging valve

BTB bus tie breaker

C

CAPT captain

CDS common display system

CDU control display unit

CIC corrosion-inhibitingcompound

CP control panel

CRT cathode ray tube

D

DC,dc direct current

DEU display electronic unit

DFCS digital flight controlsystem

FDAU flight data acquisition unit

DH decision height

DLD dynamic load damper

DME distance measuringequipment

DMM data memory module

DU display unit

E

EAU engine accessory unit

ECS environmental controlsystem

ECU electronic control unit

EDP engine driven pump

EE electronic equipment

EEC electronic engine control

EFIS electronic flightinstrument system

EGT exhaust gas temperature

EIS engine instrumentsystem

EMDP electric motor-drivenpump

EPC external power contactor

ETA estimated time of arrival

F

FCC flight control computer

FDR flight data recorder

FDRS flight data recordingsystem

FMC flight managementcomputer

FMCS flight managementcomputer system

FMS flight managementsystem

FO first officer

FQIS fuel quantity indicatingsystem

FSEU flap/slat electronics unit

ft feet

FWD forward

G

G/S glide slope

gal gallon

GCB generator control breaker

GCU generator control unit

GPS global positioning system

GPSSU global positioning systemsensor unit

GPWC ground proximity warningcomputer

GRD ground

GV guide vane (may not beused)

H

HF high frequency

HGW high gross weight

HMU hydromechanical unit

HP high pressure

HPTACC high pressure turbineactive clearance control

hr hours

2 November 2000

Abbreviations and AcronymsHSI horizontal situation

indicator

I

IDG integrated drivegenerator

IDU interactive display unit

IFSAU integrated flight systemsaccessory unit

ILS instrument landingsystem

in inches

Inst instruments

INV inverter

IRS inertial reference system

ISDU inertial system displayunit

J

K

KCAS knots calibrated airspeed

kg kilogram

kVA kilovolt-ampere

L

L left

lb pounds

LCD liquid crystal display

LE leading edge

LNAV lateral navigation

LPTACC low pressure turbineactive clearance control

LRU line replaceable unit

M

m meters

MASI mach airspeed indicator

MCP mode control panel

MG main gear

MIC microphone

MSU mode select unit

MU management unit

N

N1 fan and low pressurecompressor reference

N2 high pressurecompressor reference

ND navigation display

NG nose gear

No. number

O

OOOI out of the gate, off theground, on the ground,into the gate

OVHT overheat

P

PA passenger address

pcu power control unit

PDP power distribution panel

PFD primary flight display

PRSOV pressure regulating andshutoff valve

PSI pounds per square inch

PSU passenger service unit

PTT push to talk

PTU power transfer unit

Q

R

R right

R/T-I/C receive/transmit -intercomm

RA radio altimeter

RA resolution advisory

RCP radio control panel

REU remote electronics unit

RMI radio magnetic indicator

RPM revolutions per minute

RTO refused takeoff

S

SATCOM satellite communication

SCU starter converter unit

SELCAL selective call

Stdby standby

T

TA traffic advisory

TAI thermal anti ice

TAT total air temperature

TBV transient bleed valve

TCAS traffic collision avoidancesystem

TCV temperature controlvalve

TE trailing edge

TLA thrust lever angle

TOGA takeoff / go-around

TR transformer rectifier

TR thrust reverser


November 2000 3

typ typical

U

V

VAC volts alternating current

VBV variable bleed valve

VCD vortex control device

VDC volts direct current

VHF very high frequency

VHF NAV very high frequencynavigation

VNAV vertical navigation

VOR VHF omnidirectionalrange

VR voltage regulator

VSV variable stator vanes

W

WTAI wing thermal anti ice

WTRIS wheel-to-rudder interfacesystem

WXR weather radar

X

Y

Y/D yaw damper

Z

b737 ng gen fam

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