b737 system diagrams -...

B737

System Diagrams

Electrical

Pneumatic

Engine Oil and Fuel

Engine Anti-ice

Wing Anti-ice

Hydraulic

Hydraulic System A

Hydraulic System B

Hydraulic Standby System+

Ailerons & Spoilers

Elevators

Rudder

NG Electrical

NG Hydraulic

NG Trim Air

NG Fuel

NG MCP

737 SCHEMATICSThese schematics are available at:www.fmcguide.comUpdated: May 17, 2003 PNEUMATIC SYSTEM 300 thru 800

HYDRAULIC SCHEMATIC

Trim airmodulatingvalves

Cockpit supply duct

(8-9-B2) differences:2 recirc fans2 sets of left sidewall risers -location of which can be seen fromoutside a/c where windows havelarge spaces above wing root.No duct limit sensor or tempanticipatorSecond zone temp bulb added toaft pass cabin

asp. TATprobe

OFFAUTOHIGH

OFFAUTOHIGH

5th

9th

WAIvalve

hyd resStartvalve

EAIvalve

RTPACK

9th stagemodulating

and SOV

LTPACK

5th

9th

WING-BODYOVERHEAT

PACKTRIP OFF

BLEEDTRIP OFF

WING-BODYOVERHEAT

PACKTRIP OFF

PP

DUCTOVERHEAT

T T

DUCTOVERHEAT

AUTO

ISOLATIONVALVECLOSE

OPEN

Trim airpressureregulatorand SOV(8-9-B2)

OFF

ON

ZONETEMP

CONT CAB

ZONETEMP

FWD CAB

APU

OFF

ONBleedmodulating

and SOV

Groundpneumaticsconnection

TT

P P

OFF

ON

PACK

(-6-7-B)

(8-9-B2)

LeftElectronicController

Left PrimaryPack ControlRight Stby

Pack ControlBackup

Flight DeckZone Temp

ControlAFT CAB

Zone TempControl

LeftRam AirControl

RightElectronicController

Right PrimaryPack Control

Left StbyPack Control

PrimaryFlight DeckZone Temp

ControlFWD CAB

Zone TempControlRight

Ram AirControl

(8-9-B2)

H2Otank

COWLANTI-ICE

COWLANTI-ICE

BLEEDTRIP OFF

P P

DistributionManifold

MixManifold

GroundPre conditioned

Air

Left

Side

wal

l Ris

er

Right SidewallRiser

Passenger Cabin Overhead Distribution Duct

Diffuser Outlets

Diffuser Outlets

precooler

flow controland SOV

AFTCAB

FWDCAB

view fromaft cabin

CONTCAB

ZONETEMP

AFT CAB

T

T

T

(-8-9)Left

Recircfan

T1 zone/supply duct temp bulbpass cabin above 4th windowcockpit in ceiling

T2 duct temp anticipatorT3 duct limit sensorT4 zone/duct overheat switch (190F)T5 zone/duct overheat switch (250°F)T3

T2T1

T5

T4

T4

T4

T5 T2

T3

RightRecirc

fan

FILTERFILTER

collectorshroud

collectorshroud

(8-9-B2)(8-9-B2)

precoolercontrolvalve

TAI groundovht sw

T

DuctSensors

T

FLIGHTSPOILERS

FLIGHTSPOILERS

AUTOSLATSLEDs

AILERONS

RUDDER

ELEVATOR ANDELEV FEEL

ALTERNATENOSE

WHEELSTEERING(optional)

A/P AYAW

DAMPER

NORMALBRAKES

GROUNDSPOILERS

LANDINGGEAR

LANDINGGEAR

TRANSFERUNIT

ALTERNATENORMAL

TRAILINGEDGEFLAPS

PTU

RT TRWTRISSTBY YAW DAMP6-7-8

LT TR

NOSEWHEEL

STEERING

ALTERNATEBRAKES

AUTOBRAKES

A/P B

PTUCONTROL

VALVE

shuttlevalve

M P

filter

temperature switch

pressure switch

fuse

restrictor

flow limiter

return

A & B pressure

supply

standby pressure

ENG 1 ELEC 2

A

45-50 psipneumatic

pressure

FireHandle

Q

P

GROUNDSERVICE

(3-4-5)

ELEC 1 ENG 2

P

B

FireHandle

fill and balance line

GROUNDSERVICE

45-50 psipneumaticpressure

M

STBY casedrain

ELEC 1 ENG 2

B

FireHandle


Q

(6-7-8)

737 SCHEMATICSThese schematics are available at:www.fmcguide.comUpdated: May 17, 2003

300 / 400 / 500 ELECTRICAL SCHEMATIC600 / 700 / 800 ELECTRICAL SCHEMATICKEY

normalpoweralternatepowerAC buses haverounded corners

Standby PowerSwitch relationship

AUTO - closedOFF - openBAT - open

1

GRDPWROFF

ON

GRD POWERAVAILABLE

EPC 1

EXTTR EXT DC

Ground RefuelingPower Select

relay-R1028 vDCsw. HotBat Bus

EXTAC BUS EXT PWRAC EXT

PWR RECEP

(refueling panel)

BUS TRANSOFF

AUTO

transfer relaysR3 and R4

Gnd SrvcXFR Relay

MAIN BUS 1

GEN OFFBUS

APU GENOFF BUS

MAIN BUS 2

OFF

ON

OFF

ONGEN 1 APU GEN GEN 2

GROUND ONSERVICE OFF

TRANSFERBUS 1

GEN BUS 1

alternatepower to

BATT CHGR

TR3 Input-R329

R37 R328, R356,R330, and R562 onback of P6-2 panel.

GB 1

APUGB 1

BTB 1

V

ATR3TR1 A TR2 A

GEN OFFBUS

GEN BUS 2

TRANSFERBUS 2

FV AC STANDBY

BUS

normalpower to

BAT CHGR

GND SERVBUS

Auto StbyPower-R37

1

OFF

ON

V

V

APUStarter

V

DC STANDBYBUS

SWITCHEDHOT BAT BUS

HOT BAT BUS

BAT BUS

BATCHGR

EXT DCRECEPTACLE

DC BUS 2 V

V

A

BAT

Gen Power ControlRelay-R41

Auto StbyPower-R37

BATswitch

diodeM1220

Battery xfr-R2

Two relays:Bat Bus - R1Bat Bus Manual - R326 [BAT]

R41 closes when bat sw.is ON, connecting batteryto switched hot bat bus.

1

Battery chargertransfer relay

- R89

fromMainBus 2

Battery ovhtAPU startinterlock

Batterybus

relays

R1 energized if TR3looses power. R2 is de-energized. Battery thenprovides power to batbus.

R329 and R2 areenergized when bat sw.is ON and main bus 2is energized.R2 disables R1

TR3 disconnect -R9

DC BUS 1

OFF

STANDBYPOWER

V

ATR3TR1 A TR2 A

BAT AUTO

BAT BUS

Two relays:Auto Stby Power - R37Manual Stby Power - R328

V F

INV

StbyPowerOff- R356

R328 energizedwith Stby Powersw. in BAT andconnects inverterto AC Stby bus.

Two relays:Auto Stby Power - R37Manual Stby Power - R328

R330

FV AC STANDBY

BUS

STBY PWROFF

BAT BUS

R37 is de-energizedif DC bus 1 or AC xfrbus 1 lose power,which connectsinverter to AC stbybus and battery busto DC stby bus.

TRANSFERBUS 1

Auto StbyPower-R37

1



AUTO - openOFF - openBAT - closed

2

1

KEYnormalpoweralternatepowerAC buses haverounded corners

GRDPWROFF

ON

GRD POWERAVAILABLE

EPC

EXT PWRreceptacle

EXT PWREXT

AC BUS

GRDSERVswitch

TR

R634 controls the powersource selection of the groundservice DC bus. It energizesto let this bus receive powerfrom DC bus 1 when you pushthe ground service switch.

EXT ACPWR RECEP

(refueling panel)EXT DC

ATR1 AV

ATR2TR3

V

fromDC BUS 1

DC BUS 2Stby Norm - K5V

OFF

ON

VDC BUS 1

BAT OFF AUTO

STANDBYPOWER

bus tie - R9

SWITCHEDHOT BAT BUS

APUStarter

Sw. Hot Bat BusRelay - K8

BAT switch

GRD SRVCEDC BUS

1

diode

Bat Bus Norm - K2

K8 energized whenbattery switch is ONor when airstairhandle is in Stby.

K1 energizes to let thebattery bus receivepower from the batteryor the battery charger.It energizes when thebattery switch is ONand TR3 has no power.

K2 energizes to let thebattery bus receivepower from TR3.

If TR3 fails, K2 opensand K1 closes

Ground ServBus - R634

BAT

V

A

V DC STANDBYBUS

AUXBAT

(option)dual batteryRCCB-J9AUX

BATCHGR

BATCHGR

APUstart relay

R9 energizes to connect DC bus 1 and DCbus 2 in parallel. The relay energizes when:- the Bus Tran switch is in AUTO- xfr bus 1 or xfr bus 2 has power- the autopilot system is not in the approach

mode with glideslope capture.

BAT BUS

HOT BAT BUS

BUS TRANSOFF

AUTO

OFF

ON

OFF

ONGB 1

APUGB 1

GEN 1 APU GEN GEN 2

APU GENOFF BUS

GALLEY BUSA-B

GEN OFFBUS

SOURCEOFF

GEN OFFBUS

MAIN BUS 1

SOURCEOFF

GND SERVBUS 1

GALLEY BUSC-D

MAIN BUS 2

GND SERVBUS 2

TRANSFERBUS 1

TRANSFERBUS 2

power toBAT CHGRStby Norm

- K5

Gnd SrvcXFR Relay 1

Gnd SrvcXFR Relay 2

1

R622 energizes to letTR3 receive powerfrom xfr bus 1 whenxfr bus 2 loses power.Bus Tran must be in

Auto

Load Shed Relays

fromGroundServiceswitch

BTB 1

AV

AATR1 TR2TR3

TR3 XFR - R622

FV AC STANDBY

BUS

power toAUX BAT

CHGRFV AC STANDBY

BUS

BAT BUS

2Stby DCAltn - K3

Bat Bus Altn - K1

V F

2

HOT BAT BUS

BAT

V

A

StaticInverter

RCCB-J9Stby Norm - K5

V DC STANDBYBUS

AUXBAT

(option)dual batteryRCCB-J9

K3 energized when:- Bat switch ON and Stby Power in AUTO,- either or both transfer bus 1 and DC bus 1

have no power or,- Stby Power is in BAT.K3 opens if:- DC bus 1 and transfer bus 1 have power or,- Stby Power is OFF.

K5 energized when:- Stby Power in AUTO and both DC bus 1 and

transfer bus 1 have no power or,- Stby Power is in BAT.K5 opens if:- either transfer bus 1 or DC bus 1 has no

power

Static Inverter RCCB,K3, and K5 get nosignals when Stbypower switch is OFF

INV

STBY POWEROFF

737 SCHEMATICSThese schematics are available at:www.fmcguide.comUpdated: May 17, 2003

OILTANK

SPARVALVE

to BEARINGS ANDGEAR BOXES

SPAR VALVECLOSED

fromFUEL TANK

OILQTY

MEC

ENGINE FUELVALVE

LOW OILPRESS

PMC

FILTER

HIGH PRESSUREFUEL PUMP

FUELFLOW

OILPRESS

FUELFILTER

FILTERBYPASS

FUELFILTER

diffpress

SCAVENGEFILTER

OIL FILTERBYPASS

SCAVENGEPUMPS

OILRETURN

diffpress

forwardsump

aftsump

CHIPDETECTORS

SERVOFUEL HEATER

FUEL / OILHEAT EXCHANGER

OILPUMP

LOW PRESSUREFUEL PUMP

drive shaft

OILTEMP

ENGINE OILFUEL FEED

RETURN FUEL

OILTANK

viaEEC

viaEEC


SPARVALVE


SPAR VALVECLOSED

fromFUEL TANK

OILQTY

HMU

ENGINE FUELVALVE

LOW OILPRESS

EEC

SERVO FUELHEATER

FUELFLOW

OILTEMP

OILPRESS

diffpress

FUELFILTER

FILTERBYPASS

viaEEC

SCAVENGEFILTER

OIL FILTERBYPASS

ENG VALVECLOSED

diffpress

CHIPDETECTORS

OILRETURN

forwardsump

aftsump

SCAVENGEPUMPS

drive shaft

IDG OILCOOLER



OILPUMP

ENGINE OILFUEL FEED

RETURN FUEL

Tank 1

Centertank

Tank 2Surge tank

Bypassvalve

Refilllines

toengine

toengine

Fuel pumpprobe (inlet)

Rearspar

Frontspar

Sparvalve Defuel

valve

Fuel station

APU fuelSOV

APU fuelline

Center tankboost pumps

Forwardboost pump

Aft boostpump

Jetpump

Motiveflow inletMotive

flow outlet

Crossfeedvalve

Sparvalve Defuel

valve

Fuel station

Crossfeedvalve

Tank 1

Centertank

Tank 2Surge tank

Motiveflow inlet

Motiveflow outlet

Bypassvalve

Aft boostpumpcenter tank

boost pumps

Forwardboost pump

APU fuelSOV

APU fuel line

Refilllines

toengine

toengine

Jetpump


Rearspar

Frontspar

600 / 700 / 800 FUEL SCHEMATIC

300 / 400 / 500 FUEL SCHEMATIC

1

1

1

1

737 SCHEMATICSThese schematics are available at:www.fmcguide.comUpdated: Nov 5, 2003

NG ELECTRICAL SCHEMATIC

NG HYDRAULIC SCHEMATIC

AUTOSLATSLEDs

AILERONS

RUDDER

ELEVATOR ANDELEV FEEL

PTUCONTROL

VALVEPTU

M P

ELEC 1 ENG 2

B

FireHandle


fill and balance line

NORMALBRAKES

AUTOBRAKES

YAWDAMPER

A/P B

FLIGHTSPOILERS

Q

TRAILINGEDGEFLAPSALTERNATE

NOSEWHEEL

STEERING

ALTERNATE

GROUNDSERVICE

P

RT TR

ENG 1 ELEC 2

A

45-50 psipneumatic

pressure

FireHandle

A/P A

Q

FLIGHTSPOILERS

LANDINGGEAR

LANDINGGEAR

TRANSFERUNIT

NOSEWHEEL

STEERING

ALTERNATEBRAKES

P

GROUNDSERVICE

GROUNDSPOILERS

NORMAL

LT TRshuttlevalve

M

STBY casedrain

Q

WTRISSTBY YAW DAMP

filter

temperature switch

pressure switch

fuse

restrictor

flow limiter

return

A & B pressure

supply

standby pressure



AUTO - openOFF - openBAT - closed

2

1

KEYnormalpoweralternatepowerAC buses haverounded corners

GRDPWROFF

ON

GRD POWERAVAILABLE

EPC

EXT PWRreceptacle

EXT PWREXT

AC BUS

GRDSERVswitch

TR

R634 controls the powersource selection of the groundservice DC bus. It energizesto let this bus receive powerfrom DC bus 1 when you pushthe ground service switch.

EXT ACPWR RECEP

(refueling panel)EXT DC

ATR1 AV

ATR2TR3

V

fromDC BUS 1

DC BUS 2Stby Norm - K5V

OFF

ON

VDC BUS 1

STANDBYPOWER

bus tie - R9

SWITCHEDHOT BAT BUS

APUStarter

Sw. Hot Bat BusRelay - K8

BAT switch

GRD SRVCEDC BUS

1

diode

Bat Bus Norm - K2

K8 energized whenbattery switch is ONor when airstairhandle is in Stby.

K1 energizes to let thebattery bus receivepower from the batteryor the battery charger.It energizes when thebattery switch is ONand TR3 has no power.

K2 energizes to let thebattery bus receivepower from TR3.

If TR3 fails, K2 opensand K1 closes

Ground ServBus - R634

V

A

V DC STANDBYBUS

(option)dual batteryRCCB-J9AUX

BATCHGR

BATCHGR

APUstart relay

R9 energizes to connect DC bus 1 and DCbus 2 in parallel. The relay energizes when:- the Bus Tran switch is in AUTO- xfr bus 1 or xfr bus 2 has power- the autopilot system is not in the approach

mode with glideslope capture.

BAT BUS

HOT BAT BUS

BAT

BUS TRANSOFF

AUTO

OFF

ON

OFF

ONGB 1

APUGB 1

GEN 1 APU GEN GEN 2

APU GENOFF BUS

GALLEY BUSA-B

GEN OFFBUS

SOURCEOFF

GEN OFFBUS

MAIN BUS 1

SOURCEOFF

GND SERVBUS 1

GALLEY BUSC-D

MAIN BUS 2

GND SERVBUS 2

TRANSFERBUS 1

TRANSFERBUS 2

power toBAT CHGRStby Norm

- K5

Gnd SrvcXFR Relay 1

Gnd SrvcXFR Relay 2

1

R622 energizes to let TR3receive power from xfr bus 1when xfr bus 2 loses power.Bus Tran must be in Auto

Load Shed Relays

fromGroundServiceswitch

BTB 1

AV

AATR1 TR2TR3

TR3 XFR - R622

FV AC STANDBY

BUS

power toAUX BAT

CHGRFV AC STANDBY

BUS

BAT BUS

2Stby DCAltn - K3

Bat Bus Altn - K1

V F

2

HOT BAT BUS

V

A

StaticInverter

RCCB-J9Stby Norm - K5

V DC STANDBYBUS

dual batteryRCCB-J9

K3 energized when:- Bat switch ON and Stby Power in AUTO,- either or both transfer bus 1 and DC bus

1 have no power or,- Stby Power is in BAT.

K3 opens if:- DC bus 1 and transfer bus 1 have power

or,- Stby Power is OFF.

K5 energized when:- Stby Power in AUTO and DC bus 1 or

transfer bus 1 have no power or,- Stby Power is in BAT.

K5 opens if:- transfer bus 1 and DC bus 1 has power

Static Inverter RCCB,K3, and K5 get nosignals when Stbypower switch is OFF

INV

STBY POWEROFF

BAT

BAT OFF AUTO


OILTANK

viaEEC

viaEEC


SPARVALVE


SPAR VALVECLOSED

fromFUEL TANK

OILQTY

HMU

ENGINE FUELVALVE

LOW OILPRESS

EEC

SERVO FUELHEATER

FUELFLOW

OILTEMP

OILPRESS

diffpress

FUELFILTER

FILTERBYPASS

viaEEC

SCAVENGEFILTER

OIL FILTERBYPASS

ENG VALVECLOSED

diffpress

CHIPDETECTORS

OILRETURN

forwardsump

aftsump

SCAVENGEPUMPS

drive shaft

IDG OILCOOLER



OILPUMP

ENGINE OILFUEL FEED

RETURN FUEL

Sparvalve Defuel

valve

Fuel stationTank 1

Centertank

Tank 2Surge tank

Bypassvalve

APU fuelSOV

APU fuelline

Refilllines

toengine

toengine


Rearspar

Frontspar

Motiveflow inlet

Motiveflow outlet

Jetpump

Crossfeedvalve Aft boost

pumpCenter tankboost pumps

Forwardboost pump

NG FUEL SCHEMATIC

1

1

NG ENGINE FUEL AND OIL SCHEMATIC

Sparvalve Defuel

valve

Fuel stationTank 1

Centertank

Tank 2Surge tank

Bypassvalve

APU fuelSOV

APU fuelline

Refilllines

toengine

toengine


Rearspar

Frontspar

Aux tankfuel valves

Cabin pressure

Fwd auxtankgroup

Aux fuel transfervalves (2)

Aux tank ventvalves (2)

Bleed air line and valve

Dry bay

Aux tankisolation valve

Additionalcells

Master cell

tank-to-ambient 4.5psi diff press switch

Cabin pressure

Aft auxtankgroup

Aux fuel transfervalves (2)

Aux tank ventvalves (2)

Bleed air line and valve

Dry bay

Master cell

Additionalcells tank-to-ambient 4.5

psi diff press switch


PNEUMATIC SYSTEM 600 thru 900

Trim airmodulatingvalves

Cockpit supply duct

(8-9-B2) differences:2 recirc fans2 sets of left sidewall risers -location of which can be seen fromoutside a/c where windows havelarge spaces above wing root.No duct limit sensor or tempanticipatorSecond zone temp bulb added toaft pass cabin

asp. TATprobe

OFFAUTOHIGH

OFFAUTOHIGH

5th

9th

WAIvalve

hyd resStartvalve

EAIvalve

RTPACK

9th stagemodulating

and SOV

LTPACK

5th

9th

WING-BODYOVERHEAT

PACKTRIP OFF

BLEEDTRIP OFF

WING-BODYOVERHEAT

PACKTRIP OFF

PP

DUCTOVERHEAT

T T

DUCTOVERHEAT

AUTO

ISOLATIONVALVECLOSE

OPEN

Trim airpressureregulatorand SOV(8-9-B2)

OFF

ON

ZONETEMP

CONT CAB

ZONETEMP

FWD CAB

APU

OFF

ONBleedmodulating

and SOV

Groundpneumaticsconnection

TT

P P

OFF

ON

PACK

(-6-7-B)

(8-9-B2)

LeftElectronicController

Left PrimaryPack ControlRight Stby

Pack ControlBackup

Flight DeckZone Temp

ControlAFT CAB

Zone TempControl

LeftRam AirControl

RightElectronicController

Right PrimaryPack Control

Left StbyPack Control

PrimaryFlight DeckZone Temp

ControlFWD CAB

Zone TempControlRight

Ram AirControl

(8-9-B2)

H2Otank

COWLANTI-ICE

COWLANTI-ICE

BLEEDTRIP OFF

P P

DistributionManifold

MixManifold

GroundPre conditioned

Air

Left

Side

wal

l Ris

er

Right SidewallRiser

Passenger Cabin Overhead Distribution Duct

Diffuser Outlets

Diffuser Outlets

precooler

flow controland SOV

AFTCAB

FWDCAB

view fromaft cabin

CONTCAB

ZONETEMP

AFT CAB

T

T

T

(-8-9)Left

Recircfan

T1 zone/supply duct temp bulbpass cabin above 4th windowcockpit in ceiling

T2 duct temp anticipatorT3 duct limit sensorT4 zone/duct overheat switch (190F)T5 zone/duct overheat switch (250°F)T3

T2T1

T5

T4

T4

T4

T5 T2

T3

RightRecirc

fan

FILTERFILTER

collectorshroud

collectorshroud

(8-9-B2)(8-9-B2)

precoolercontrolvalve

TAI groundovht sw

T

DuctSensors

T

b737 system diagrams -...

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