3 engine system

Created by Rafik Chabou ENGINE CF6-80E1 General Familiarization

３３

33 -- EE nn gg ii nn ee SS yy ss tt ee mm ss Fuel System

ObjectivesGiven an objective exercise, you will be able to:

Identify the location of the components of the fuel system Identify the components of the fuel system Identify the purpose of the components of the fuel system Identify the purpose of the fuel system Identify the operation of the fuel system

OverviewThe fuel system consists of different components that function together todistribute fuel to different engine systems and components. The fuelsystem consists of the following components:

Fuel pump Fuel/oil heat exchanger Fuel filter Servo fuel heater Hydromechanical unit (HMU) IDG fuel/oil heat exchanger Fuel flow transmitter Fuel manifolds Fuel nozzles Combustor drain valve


３４

In this lesson, you will learn about the location, identification, and purposeof the components, and the operation of the fuel system.

Location Left Side ViewThe fuel system consists of components that are listedbelow.

The fuel manifolds are mounted around thecircumference of the CRF.

The fuel nozzles are mounted around thecircumference of the CRF.

Location Right Side ViewThe fuel system consists of components that arelisted below.

The fuel pump is installed on the right side ofthe aft face of the AGB.

The fuel/oil heat exchanger is installeddirectly on the fuel pump on the inboard side.

The fuel filter is installed on the outboard side of the fuel pump.


３５

The servo fuel heater is installed on the right side of the accessorygearbox, just below the heat shield.

The hydromechanical unit (HMU) is bolted to the front face of theAGB, just below the IDG air/oil cooler.

The IDG fuel/oil heat exchanger is on the right side of the AGB, justbelow the servo fuel heater.


３６

The fuel flow transmitter is on the right side of the AGB, just aft ofthe HMU.

The combustor drain valve is installed on the seventh stage LPT coolingmanifold at the 5:30 position.

PurposeThe fuel system receives fuel from the aircraft fuel tank. The fuel system

then pressurizes and filters the fuel before supplying the correct quantity

of fuel at the required pressure to the combustor for burning.

OperationFuel from the aircraft fuel tank enters the centrifugal boost stage of the

fuel pump. The fuel then flows to the high pressure stage after passing


３７

through the strainer. From here, the fuel flows to the fuel/oil heat

exchanger and the fuel filter. The fuel filter removes impurities from the

fuel. The clean fuel then enters the HMU. A portion of the fuel also enters

the servo fuel heater, where the fuel gets heated before flowing into the

HMU.

The fuel metering valve in the HMU supplies the correct quantity of fuel to

the fuel manifold through the fuel flow transmitter. From the fuel manifold,

the fuel is distributed equally to 30 nozzles. The HMU ensures that excess

fuel inside it is routed back to the fuel pump through the IDG fuel/oil heat

exchanger. In case of an engine no-start, leaking fuel from the combustion

chamber drains overboard through the combustor drain valve.

Fuel PumpLocation: The fuel pump is mounted on the right side of the aft face of theaccessory gearbox.

Identification: The fuel pump is driven directly by the AGB. The fuel pumpconsists of the following components:

Centrifugal boost stage High pressure stage Relief valve Drive shaft Interstage strainer

The fuel pump also has mounting

surfaces for the fuel filter and

the fuel/oil heat exchanger.

Purpose: The fuel pump is

designed to provide sufficient

fuel flow and pressure to meet engine burn flow requirements. The fuel


３８

pump is also designed to supply servo fuel flow to all fuel-powered servo

controls on the engine.

Fuel/Oil Heat ExchangerLocation: The fuel/oil heat exchanger is mounted directly on the fuel pump

on the inboard side.

Identification: The fuel/oil heat

exchanger is made up of a number of

chambers containing tubes and baffles.

The fuel/oil heat exchanger also has an

oil bypass valve.

Purpose: The function of the fuel/oil heat exchanger is to cool the engine oiland to heat the engine fuel. Cooling of the oil helps in maintaining the oilviscosity, and heating of the fuel prevents icing and improves fuelatomization.

Fuel FilterLocation: The fuel filter is installed on the outboard side of the fuel pump.

Identification: The fuel filter contains a removable

filter bowl with a disposable filter element. The

bowl contains an inlet for fuel from the fuel pump,

and an outlet for fuel to the HMU. The fuel filter

also has a servo outlet port for sending a small

quantity of fuel to the servo fuel heater.

Purpose: The fuel filter is used to remove impurities

from the fuel before the fuel flows to the HMU.


３９

Servo Fuel HeaterLocation: The servo fuel heater is mounted on the right side of theaccessory gearbox, just below the heat shield.

Identification: The servo

fuel heater is a fuel/oil

heat exchanger containing

chambers with tubes and

baffles. The servo fuel

heater also contains a delta

pressure oil bypass valve

and a thermal bypass valve.

Purpose: The servo fuel heater provides additional heating of the fuelbefore it flows to the servo section of the HMU.

Hydromechanical Unit(HMU)Location: The hydromechanical

unit (HMU) is bolted to the front

face of the AGB, just below the

IDG air/oil cooler.

Identification: The HMUcontains the following valves:

Fuel metering valve (FMV) Pressurizing and shutoff valve (PSOV)

In addition, the HMU contains ports for providing interfaces with fuel inlets

and outlets to and from different engine components. The HMU also

contains connections for the ECU channel A and channel B connectors.


４０

Purpose:

Meters and distributes the correct amount of fuel for combustionunder all operating conditions

Provides servo fuel pressure for the positioning of actuators andvalves of the engine systems

IDG Fuel/Oil Heat ExchangerLocation: The IDG fuel/oil heat exchanger is on the right side of the AGB,just below the servo fuel heater.

Identification: The IDG fuel/oil heat

exchanger consists of a rectangular metal

box with inlet and outlet connections for

fuel. The inside of the box contains a

number of chambers, baffles, and hollow

tubes. The IDG fuel/oil heat exchanger

also contains a bypass valve.

Purpose: The IDG fuel/oil heat exchangerhelps to cool the IDG oil.

Fuel Flow TransmitterLocation: The fuel flow transmitter is on the right side of the AGB, just aftof the HMU.

Identification: The fuel flow

transmitter is an electro-mechanical

component that consists of a rotor

and a set of magnets with electrical

coils. An electrical connector sends

signals from the transmitter to the

ECU.


４１

Purpose: The fuel flow transmitter measures the total mass of fuel flow to

the engine combustor. The fuel filter transmitter sends this information to

the ECU as an electrical signal.

Fuel ManifoldsLocation: The fuel manifolds are mounted around the circumference of the

CRF.Identification: The engine contains a

set of three fuel manifolds. Of these,

two are fuel-feed manifolds and the

third is the drain manifold. Each of the

three manifolds is divided into two

halves, one for each side of the engine.

Purpose: The two fuel feed manifolds

distribute metered fuel from the HMU

to the 30 fuel nozzles. The drain manifold collects leaking fuel that may leak

from the nozzle connections.

Fuel NozzlesLocation: The fuel nozzles are located around thecircumference of the CRF.Identification: The engine contains 30 fuel nozzles.

Each nozzle contains a check valve, primary, and

secondary fuel flow circuits, and a fuel divider valve.

Purpose: The fuel nozzles distribute atomized fuel to

the combustor for combustion during starting, and for

low and high power engine operations.


４２

Combustor Drain ValveLocation: The combustor drain valve is mounted

on the seventh stage LPT cooling manifold at the

5:30 position.

Identification: The combustor drain valve is a

spring-loaded drain valve with inlet and outlet

fittings.

Purpose: The combustor drain valve allows fuel

and other liquids to drain overboard out of the rear of the engine nacelle.

Control SystemObjectivesGiven an objective exercise, you will be able to:

Identify the location of the components of the control system Identify the components of the control system Identify the purpose of the components of the control system Identify the purpose of the control system Identify the operation of the control system

OverviewThe control system consists of the following components that provide enginecontrol under all operating conditions:

Electronic control unit (ECU) Permanent magnet alternator (PMA) Engine rating/identification plug N1 sensor N2 sensor T4.9 (EGT) sensors Ps3 sensor PO sensor T12 sensor Ps12 sensor


４３

T2.5 sensor T3 sensor Fuel temperature sensor Thrust reverser position feedback RVDT sensor Optional sensors (T5 /Ps14 /P2.5 /P4.9)

In this lesson, you will learn about the location, identification, and purposeof the components, and the operation of the control system.

Location Left Side View

The components of the control system are listed below. The electronic control unit (ECU) is on the fan case at the 8:30

position. The permanent magnet alternator (PMA) is mounted to the left of the

lube and scavenge pump on the forward side of the AGB.

The T4.9 exhaust gas temperature (EGT) sensors are installed aroundthe circumference of the low pressure turbine (LPT) case.


４４

The T12 sensor is installed on the forward fan case at the 12 o'clockposition.

The T3 sensor is installed on the CRF at the 11:30 position.

The T5 sensor is an optional control system componentthat is installed on the turbine rear frame (TRF) atthe 9:30 position.

The engine rating/identification plug is connected tothe J11 connector on the ECU and is also attached tothe fan case.


４５

The T2.5 sensor is installed on the aft side of the fan frame at the7:30 position.

The Ps12 sensors are installed at approximately 10:30 and 1:30positions on the forward fan case.

The PO sensor is at the bottom of the ECU.


４６

The Ps14 sensor is an optional control system component that is on theaft fan case at the 10:30 position.

The P2.5 sensor is an optional control system component that isinstalled on the aft side of the fan frame at the 7:30 position.

The Ps3 sensors are inside the ECU. Bleed air is ported from the 3o'clock position on the CRF to the sensors through a tubing.


４７

Location Right Side ViewThe components of the control system are listed below.

The N1 sensor is installed on the fan frame at the 2 o'clock position.

The N2 sensor is installed on the front right side of the accessorygearbox, inboard of the HMU.

The P4.9 sensor is an optional control system that is on the LPT caseat the 3:30 position.


４８

The fuel temperature sensor is installed between the fuel flowtransmitter and the fuel manifolds.

LocationThe components of the control system are listed below.

The thrust reverser RVDT (rotary variable differential transducer)

sensor is installed on a drive pad on top of the center drive unit (CDU)

of the thrust reverser.


４９

PurposeThe control system provides a complete range of engine control under all

steady state and transient state engine operating conditions. This is done by

accurately controlling the fuel flow, primary and parasitic airflows, internal

clearances, start sequences and igniter operation. The system also controls

the thrust reverser system operation.

Operation

The electrically powered ECU is the primary component of the engine control

system. The ECU receives digital and analog data from different parts of

the engine and the aircraft. Engine data includes information about speeds,

pressures, and temperatures. This information is sent to the ECU by sensors

mounted on different locations on the engine. The ECU also receives

feedback from various engine actuators and valves. Information from the air

system, the start system, the IDG system, the oil system, and the thrust

reverser system is also sent to the ECU.


５０

The aircraft data includes information about the position of the thrust

control levers and flight deck switches. In addition, information from the

computers and display systems of the aircraft is also routed to the ECU

The ECU processes different engine and aircraft inputs. The ECU controls

the position of the fuel metering valve in the HMU so that the correct

amount of fuel is sent to the combustion chamber, the engine actuators, and

the valves. The control system also correctly positions the start system, the

ignition system, and the thrust reverser system.

Electronic Control UnitLocation: The electronic control unit (ECU) is on the fan case at the 8:30position.

Identification: The ECU is

a computer that is enclosed

in an aluminum casing. The

ECU contains electrical

connectors for interfacing

with different engine and

aircraft systems and

components.

Purpose:

Controls the functioning of different engine systems and componentsunder all operating conditions

Provides inputs for display on the flight deck Checks for malfunctioning of important engine systems and

components Allows basic maintenance testing of the engine systems and

components


５１

As an optional feature, the ECU monitors the functioning of certainengine parameters to help forecast trends in engine performance

Permanent Magnet AlternatorLocation: The permanent magnet alternator (PMA) is mounted to the left ofthe lube and scavenge pump on the forward side of the AGB.

Identification: The PMA

consists of a three-phase

magnetic rotor that is contained

in a stator housing.

Purpose: The PMA provides

electrical power to the ECU

during regular engine operation.

Engine Rating/Identification PlugLocation: The engine rating/identification plug is connected to the J11connector on the ECU and is also attached to the fan case.

Identification: The engine

rating/identification plug is an

electrical plug that is attached to the

fan case by a lanyard.

Purpose: The plug provides the thrust

and engine configuration information to

the ECU for the correct control of

engine valves and actuators.


５２

N1 SensorLocation: The N1 sensor is installed on the fan frame at the 2 o'clockposition.

Identification: The N1 sensor is a

magnetic pulse-type sensor with

three electrical coils and two

electrical connectors.

Purpose: The N1 sensor provides two

fan speed signals to the ECU and one

to the flight deck. The fan speed

signals help the ECU to perform the engine control functions, and to display

the N1 indication on the engine warning display (EWD) on the flight deck.

N2 SensorLocation: The N2 sensor is installed on the front right side of the accessorygearbox, inboard of the HMU.

Identification: The N2

sensor is a magnetic

pulse-type sensor with

three electrical coils and

two electrical connectors.

Purpose: The N2 sensor

provides two core speed

signals to the ECU and one

to the flight deck. The core engine speed signals help the ECU to perform

the various engine control functions, and to display the N2 indication on the

engine warning display (EWD) on the flight deck


５３

T4.9 (EGT) Sensors

Location: The T4.9 exhaust gas temperature (EGT) sensors are installedaround the outside of the low pressure turbine(LPT) case.Identification: There are eight T4.9 (EGT)

sensors that protrude into the discharge

airflow from the high pressure turbine (HPT).

Four sensors are connected together using an

electrical harness and are in the upper half of

the LPT case. The remaining four sensors are

connected using a different electrical harness

and are in the lower half of the LPT case.

Purpose: The T4.9 (EGT) sensors provide the temperature signals of the

HPT discharge air to the electronic control unit (ECU). The HPT discharge

air temperature helps the ECU to carry out engine control functions. The

sensors also display the T4.9 (EGT) indication on the engine warning display

(EWD) on the flight deck.

Ps3 Sensors

Location: The Ps3 sensors are inside the ECU.Bleed air is ported from the 3 o'clock position onthe CRF to the sensors through a tubing.

Identification: There are two Ps3 sensors. Each

sensor is a pressure transducer. An air fitting

that is located at the 3 o'clock position on the CRF is used to port the air to

the two sensors.


５４

Purpose: The purpose of the Ps3 sensors is to provide compressor discharge

air pressure input to the ECU. The compressor discharge air pressure input

helps the ECU to carry out engine control functions.

PO Sensor

Location: The PO sensor is at the bottom of the ECU.

Identification: The PO sensor is the open port

on the pressure manifold that is located at the

bottom of the ECU.

Purpose: The PO sensor provides ambient air

pressure input to the ECU. The ambient air

pressure input helps the ECU to carry out engine control functions.

T12 Sensor

Location: The T12 sensor is installed on the forward fan case at the 12o'clock position.

Identification: The T12 sensor is a resistant,

thermal device that protrudes into the fan

inlet airstream.

Purpose: The T12 sensor provides a fan inlet

air temperature input to the ECU. The fan inlet

air temperature input helps the ECU to carry

out engine control functions.


５５

Ps12 Sensors

Location: The Ps12 sensors are installed at approximately 10:30 and 1:30positions on the forward fan case.

Identification: There are two Ps12 sensors, both

of which are static ports on the fan case.

Purpose: The Ps12 sensors provide the fan inlet

air pressure to the ECU to help it to carry out

engine control functions.

T2.5 Sensor

Location: The T2.5 sensor is mounted on the aft side of the fan frame atthe 7:30 position.

Identification: The T2.5 sensor is a

resistant, temperature detector-type sensor

that protrudes into the HPC inlet airstream.

Purpose: The T2.5 sensor provides the HPC

inlet air temperature input to the ECU. The

HPC inlet air temperature input helps the

ECU to carry out engine control functions


５６

T3 Sensor

Location: The T3 sensor is installed on the CRF at the 11:30 position.

Identification: The T3 sensor is a

thermocouple sensor that protrudes

into the HPC discharge airflow.

Purpose: The T3 sensor provides the

temperature of the HPC discharge

air to the ECU. The HPC discharge

air temperature helps the ECU carry

out engine control functions.

Fuel Temperature Sensor

Location: The fuel temperature sensor is installed between the fuel flowtransmitter and the fuel manifolds.

Identification: The fuel temperature sensor is

a thermocouple sensor with two junctions. The

two junctions of the thermocouple sensors are

immersed in the fuel that flows from the HMU

to the fuel manifolds.

Purpose: The fuel temperature sensor measures the temperature of the

metered fuel that is discharged from the HMU, and sends this information

to the ECU. The ECU uses this signal to control the IDG air/oil cooler

control valve.


５７

Thrust Reverser Position Feedback RVDT Sensor

Location: The thrust reverser position feedback RVDT (rotary variable

differential transducer) sensor is installed on a drive pad on top of the

center drive unit (CDU) of the thrust reverser.

Identification: The thrust reverser

position feedback RVDT sensor is an

electronic sensor with mechanical

components. The thrust reverser

position feedback RVDT sensor

contains a reduction gearbox assembly

that is attached to dual variable transducers.

Purpose: The thrust reverser position feedback RVDT sensor sendsinformation about the position of the translating cowl to the ECU.

T5 Sensor

Location: The T5 sensor is an optional control system

component that is installed on the turbine rear frame

at the 9:30 position.

Identification: The T5 sensor consists of two

thermocouples with junctions at two different locations

along the axis of the sensor.

Purpose: The T5 sensor provides the total temperature

of the LPT discharge airflow to the ECU.


５８

Ps14 Sensor

Location: The Ps14 sensor is an optional control system component that is onthe aft fan case at the 10:30 position.

Identification: The Ps14 sensor

consists of a probe that is connected to

a pressure transducer in the ECU

through an external air tube.

Purpose: The Ps14 sensor provides the

ECU with an indication of the static

pressure of the fan discharge airflow

for extended condition monitoring of the engine performance.

P2.5 Sensor

Location: The P2.5 sensor is an optional control system component that isinstalled on the aft side of the fan frame at the 7:30 position.

Identification: The P2.5 sensor is a pressure

transducer that is connected to the ECU through

an external air tube. The air tube ports air to the

ECU from the cone-shaped opening on top of the

T2.5 sensor.

Purpose: The P2.5 sensor provides the ECU with

an indication of the pressure of the HPC inlet

airstream for extended condition monitoring of

the engine performance.


５９

P4.9 Sensor

Location: The P4.9 sensor is installed at the 3:30 o'clock position on the LPTcase, just aft of the forward flange. The P4.9 sensor is optional.

Identification: The P4.9

sensor has four cone-shaped

total pressure inputs machined

into a raised boss on the

leading edge of the probe.

Purpose: The P4.9 sensor

supplies the total pressure of

the LPT inlet airflow to the

ECU for extended conditioning monitoring of the engine performance.

Air Control SystemObjectives

Given an objective exercise, you will be able to:

Identify the location of the components of the air control system Identify the components of the air control system Identify the purpose of the components of the air control system Identify the purpose of the air control system Identify the operation of the air control system

Overview

The air control system consists of different subsystems and components

that regulate air in different areas of the engine. The air control system

consists of the following subsystems and components:


６０

Bore cooling system Variable stator vane (VSV) system Variable bleed valve (VBV) system Core compartment cooling system High pressure turbine active clearance control (HPTACC) Low pressure turbine active clearance control (LPTACC) 7th stage delta pressure switches IDG air/oil cooling system

In this lesson, you will learn about the location, identification, and purposeof the components, and operation of the air control system.

Location Left Side ViewThe components of the air control system are listed below.

The bore cooling system consists of components that are installed onthe outer surface of the aft fan case and along the length of the coremodule.

The variable bleed valve (VBV) system consists of components that areinstalled around the hub of the fan frame.

The core compartment cooling system consists of components that areon the upper left-hand side of the HPC and around the engine.

The components of the low pressure turbine active clearance control(LPTACC) system are installed at the 9 o'clock position on the coreengine and also around the LPT.

The 7th stage delta pressure switches are installed at the 11:30position on the outer surface of the HPC case.


６１

Location Right Side ViewThe components of the air control system are listed below.

The high pressure turbine active clearance control (HPTACC) systemstarts at the 2 o'clock position on the HPC outer case. From thisposition, the HPTACC system extends around the outer surface of theHPT case.

The IDG air/oil cooling system consists of components that areinstalled on the right hand side of the HPC.

The VSV system consists of components that are installed on theouter surface of the HPC from the inlet guide vanes (IGV) to thestage 5 variable stator vanes.

PurposeThe purpose of the air control system is to regulate supply of air throughthe engine. This ensures proper functioning of different engine control andcooling systems, and optimizes specific fuel consumption.

OperationUsing the core speed and engine temperature inputs, the ECU regulates theopening and closing of the three bore cooling valves on the aft fan case. Thismakes sure that during cruise conditions, the engine core receives optimumprimary airflow.


６２

The ECU also uses the altitude and fan speed inputs to regulate the openingand closing of the core compartment cooling valve. This makes sure that thecore compartment receives the optimum amount of cooling airflow during alloperating conditions.

The ECU sends a signal to the hydromechanical unit (HMU) to meter fuelpressure to open or close the HPT and LPT active clearance control valves.This keeps the clearances between the HPT turbine shrouds and the HPTrotor blades and between the LPT turbine shrouds and the LPT rotor bladesto a minimum.


６３

The ECU uses the core speed, the temperature and the altitude inputs toregulate the flow of fuel from the HMU to the variable stator vane (VSV)actuators. The actuators position the variable stator vanes in the HPC toprevent stalling of the compressor and to optimize performance.

Similarly, the ECU uses the core speed, Mach number, and altitude inputs toregulate fuel flow from the HMU to the variable bleed valve (VBV) actuators.The VBV actuators position the variable bleed valves so that an optimumamount of bleed air flows from the LPC to the HPC. This flow of airoptimizes compressor performance and prevents stalling.


６４

Bore Cooling System

Location: The bore cooling system consists of components that are installedon the outer surface of the aft fan case and along the length of the coremodule.

Identification: The bore cooling

system consists of three bore cooling

valves and pneumatic tubing.

Purpose: The function of the bore

cooling system is to cool the HPC rotor.

However, during cruise conditions, the

system optimizes the primary airflow

by reducing the cooling airflow to the

bore of the HPC.


６５

VSV System

Location: The variable stator vane (VSV) system consists of componentsthat are installed on the outer surface of the HPC from the inlet guidevanes (IGV) to the stage 5 variablestator vanes.

Identification: The VSV systemconsists of the following components:

Stage 1 variable inlet guidevanes (IGV)

Stages 2 to 5 variable statorvanes

VSV actuation mechanism

Purpose: The VSV system controlsthe amount of airflow through theHPC to prevent the compressor fromstalling, and to optimize compressor performance.

VBV System

Location: The variable bleed valve (VBV) system consists of components

that are installed around the hub of the fan frame.

Identification: The system consists

of the following components:

Variable bleed valves (VBV) VBV actuation mechanism


６６

Purpose: The VBV system regulates the flow of air to the HPC by controlling

the amount of bleed from the LPC. This helps to prevent the compressor

from stalling, and also optimizes compressor performance.

Core Compartment Cooling System

Location: The core compartment cooling system consists of components thatare on the upper left-hand side of the HPC and around the engine.

Identification: The systemconsists of the followingcomponents:

Core compartment coolingvalve

Core compartment coolingmanifold

Fan discharge air duct

Purpose: The core compartment

cooling system cools and removes

fumes from the closed engine

core compartment. The core compartment cooling system provides maximum

cooling airflow to the core compartment during all operating conditions.

However, during cruise, the supply of the cooling airflow is reduced to

optimize engine performance.

HPT Active Clearance Control

Location: The high pressure turbine active clearance control (HPTACC)

system starts at the 2 o'clock position on the HPC outer case. From this

position, the HPTACC system extends around the outer surface of the HPT

case.


６７

Identification: The HPTACCsystem consists of the followingcomponents:

HPTACC valve HPTACC manifold

Purpose: The function of the

HPTACC system is to regulate

the flow of cooling air to the HPT

case and minimize clearances

between the HPT shrouds and the HPT rotor blades. This helps to improve

the specific fuel consumption of the engine.

LPT Active Clearance Control

Location: The components of the low pressure turbine active clearancecontrol (LPTACC) system are installed at the 9 o'clock position on the coreengine and also around the LPT.

Identification: The LPTACC system consists of the following components:

LPTACC valve LPTACC manifold

Purpose: The purpose of the LPTACC

system is to regulate the flow of

cooling air to the LPT case to minimize

clearances between the LPT shrouds

and the LPT rotor blades. This helps to

improve the specific fuel consumption

of the engine during cruise conditions.


６８

7th Stage Delta Pressure Switches

Location: The 7th stage delta pressure switches are installed at the 11:30position on the outer surface of the HPC case.

Identification: There are two 7th stage

delta pressure switches, both of which

are installed in a rectangular unit. Each

switch is a double-pole, double-throw

type.

Purpose: The function of the 7th stage

delta pressure switches is to monitor air pressure in the 7th stage manifolds.

In the event of a duct leakage, a fault indication signal is sent to the ECU.

IDG Air/Oil Cooling System

Location: The IDG air/oil cooling system consists of components that are

installed on the right-

hand side of the HPC.

Identification: The

IDG air/oil cooling

system consists of the

following components:

IDG air/oil cooler IDG air/oil cooler

shutoff valve


６９

Purpose: The purpose of the IDG air/oil cooling system is to regulate the

flow of fan discharge air to the IDG air/oil cooler during cruise conditions.

This is done to optimize specific fuel consumption.

Oil SystemObjectivesGiven an objective exercise, you will be able to:

Identify the location of the components of the oil system Identify the components of the oil system Identify the purpose of the components of the oil system Identify the purpose of the oil system Identify the operation of the oil system

OverviewThe oil system consists of the following components that function together

to distribute oil to engine bearings, gears, and other components for

lubrication and cooling:

Oil tank Oil tank pressurization valve Oil tank filler cap Oil tank quantity transmitter Lube and scavenge pump Oil pressure transmitters Oil pressure signal amplifier Low oil pressure switch Oil temperature sensor Master chip detector Fuel/oil heat exchanger Servo fuel heater Scavenge oil filter Scavenge oil filter differential pressure switch

In this lesson, you will learn about the location, identification, and purposeof the components, and operation of the oil system.


７０

Location Left Side ViewThe oil system consists of components that are listed below.

The master chip detector (MCD) is installed in the main scavenge lineaft of the AGB, at the 6 o'clock position.

The oil pressure signal amplifier is installed on the aft fan case atapproximately 7 o'clock position.

The oil pressure transmitters are installed on a bracket in front of thelube and scavenge pump.


７１

The low oil pressure switch is installed on the forward end of the lubeand scavenge pump.

The oil temperature sensor is installed on a flange in the oil scavengeline, just inboard of the lube and scavenge pump.

The lube and scavenge pump is installed on the forward left side ofthe AGB, just inboard of the hydraulic pump.


７２

Location Right Side ViewThe oil system consists of components that are listed below.

The oil tank is installed on the aft fan case at the 3 o'clock position. The oil tank pressurization valve is installed on top of the oil tank, to

the right of the scavenge return tube.

The oil tank filler cap is installed on the upper right side of the oiltank on top of the scupper drain.

The oil tank quantity transmitter is installed on top of the oil tank, tothe left of the scavenge return tube.


７３

The fuel/oil heat exchanger is installed on the inboard side of the fuelpump.

The servo fuel heater is installed on the right side of the AGB, justbelow the heat shield.

The scavenge oil filter is installed on the aft fan case at the 3:30position, below the oil tank.


７４

The scavenge oil filter differential pressure switch is installed on abracket at the 3:30 position on the aft fan case, just above thescavenge oil filter.

PurposeThe oil system distributes lubricating oil to the engine sump bearings, and

gears, and recycles oil from different areas of the engine for reuse. In

addition, the oil system indicates information about oil system parameters

such as oil quantity, oil pressure, and oil temperature to the ECU.


７５

OperationThe oil in the oil tank flows to the lube and scavenge pump. Here, the oil is

pressurized and sent through the oil filter to the oil nozzles in the engine

sumps, the AGB, and the transfer gearbox (TGB). A small portion of the

pressurized oil is sent to the low oil pressure switch and to the oil pressure

transmitters.

The lube and scavenge pump gathers the scavenge oil from the sumps and

the gearboxes and sends it to a common scavenge line. The scavenge oil then

flows over the oil temperature sensor and the master chip detector. Later,

the scavenge oil flows through the servo fuel heater, the fuel/oil heat

exchanger, the scavenge oil filter, and finally into the oil tank.

Signals from all oil system sensors, except the low oil pressure switch, are

transmitted to the ECU for monitoring system conditions and indications on

the flight deck.

Oil TankLocation: The oil tank is installed on the aft fan case at the 3 o'clockposition.

Identification: The oil tank is made of

aluminum, and consists of two oil chambers.

The oil tank is equipped with an internal air/oil

separator, an oil quantity sensor, an external

sight gage, a pressurizing valve, and a relief

valve.


７６

Purpose: The oil tank is a reservoir that is used to store engine oil. The oil

tank also delivers the stored engine oil to the lube and scavenge pump.

Oil Tank Pressurization ValveLocation: The oil tank pressurization valve is installed on top of the oil tank,

to the right of the scavenge return tube.

Identification: The oil tank pressurization valve is

connected to the A-sump through a vent tube.

Purpose: The oil tank pressurization valve maintains

a positive head pressure on the oil in the tank. The

positive head pressure makes sure that a constant

and pressurized oil feed is available to the lube and

scavenge pump at all times.

Oil Tank Filler CapLocation: The oil tank filler cap is installedon the upper right side of the oil tank ontop of the scupper drain.

Identification: The oil tank filler cap

contains a self-sealing flapper valve.

Purpose: The oil tank filler cap seals the

opening that is used to manually fill oil in the oil tank.


７７

Oil Tank Quantity TransmitterLocation: The oil tank quantity transmitter is installed on topof the oil tank, to the left of the scavenge return tube.

Identification: The oil tank quantity transmitter consists of

a number of reed switches and a float assembly with magnets

installed on it. The transmitter has two sensing circuits, each

of which sends signals to the ECU through separate cables.

Purpose: The transmitter indicates the oil level in the oil tank

to the ECU. The ECU then transmits this information to the

flight deck.

Lube and Scavenge Pump

Location: The lube and scavenge pump is installed on the forward left sideof the AGB, just inboard of the hydraulic pump.

Identification: The lube and

scavenge pump is a rotary vane-type

pump. The shaft of the lube and

scavenge pump is driven by the AGB.

The pump has one pressure element

and five scavenge elements. In

addition, the pump consists of six

mesh inlet screens, an outlet filter,

and an anti-static check valve.


７８

Purpose: The lube and scavenge pump delivers pressurized oil to the engine

bearing in the four sumps and to the gears in the AGB and the transfer

gearbox. In addition, the pump also collects the engine oil from the sumps

and the gearboxes for reuse.

Oil Pressure TransmittersLocation: The oil pressure transmitters are installed on a bracket in frontof the lube and scavenge pump.

Identification: There are two oil pressure

transmitters that are placed adjacent to

each other. Each transmitter is a piezo-

electric device.

Purpose: The oil pressure transmitters

provide electrical signals that indicate oil

pressure conditions within the bearing sumps.

These electrical signals are transmitted to

the ECU for display on the flight deck.

Oil Pressure Signal Amplifier

Location: The oil pressure signal

amplifier is installed on the aft

fan case at approximately 7

o'clock position.

Identification: The oil pressure

signal amplifier is an electrical


７９

component that is mounted on the aft fan case using a clamp and nut

arrangement.

Purpose: The oil pressure signal amplifier amplifies the signals receivedfrom the two oil pressure transmitters before sending them to the ECU.

Low Oil Pressure Switch

Location: The low oil pressure switch is installed on the forward end of thelube and scavenge pump.

Identification: The low oil pressure

switch consists of a Belleville-type

bellows whose motion is controlled

by a negative-rate snap ring.

Purpose: The low oil pressure switch

provides a signal to the aircraft

indicating and warning systems when

the oil pressure is low.

Oil Temperature SensorLocation: The oil temperature

sensor is installed on a flange

in the oil scavenge line, just

inboard of the lube and

scavenge pump.

Identification: The oil

temperature sensor consists

of two thermocouples that are


８０

in a stainless steel shell. An electrical connector from each thermocouple

provides an electrical signal to the ECU.

Purpose: The oil temperature sensor indicates the engine oil temperature to

the ECU. The ECU transmits the engine oil temperature information to the

flight deck on the aircraft engine warning display (EWD) system.

Master Chip Detector

Location: The master chip detector (MCD) is installed in the main scavengeline aft of the AGB, at the 6 o'clock position.

Identification: The MCD is a bayonet, three-pin

type, permanent magnet probe that is fitted in a

housing. The MCD is immersed in the scavenge oil

that is flowing from the lube and scavenge pump to

the servo fuel heater.

Purpose: The MCD traps magnetic particles that aresuspended in the scavenge oil.

Fuel/Oil Heat ExchangerLocation: The fuel/oil heat

exchanger is installed on the fuel

pump on the inboard side.

Identification: The fuel/oil heat

exchanger is made up of a number

of chambers containing tubes and

baffles. The fuel/oil heat exchanger also has an oil bypass valve.


８１

Purpose: The function of the fuel/oil heat exchanger is to cool the engine oil

and also to heat the engine fuel. Cooling of the oil helps in maintaining the oil

viscosity, and heating of the engine fuel prevents icing and improves

atomization

Servo Fuel HeaterLocation: The servo fuel heater is installed on the right side of the AGB,just below the heat shield.

Identification: The

servo fuel heater is a

fuel/oil heat exchanger

containing chambers

with tubes and baffles.

The servo fuel heater

also contains a high-

pressure, delta pressure

oil bypass valve, and a

thermal bypass valve.

Purpose: The servo fuel heater provides additional heating of the fuel

before the fuel flows to the servo section of the HMU.

Scavenge Oil Filter

Location: The scavenge oil filter is

located on the aft fan case at the 3:30

position, below the oil tank.


８２

Identification: The scavenge oil filter consists of a removable filter bowl

and a disposable filter element. The scavenge oil filter also contains a shut-

off valve and a bypass valve.

Purpose: The scavenge oil filter removes contamination from the engine oilbefore the oil flows into the oil tank.

Scavenge Oil Filter Differential Press. SwitchLocation: The scavenge oil filter differential pressure switch is installed ona bracket at the 3:30 position on the aft fan case, just above the scavengeoil filter.

Identification: The scavenge oil filter

differential pressure switch contains a

Belleville-type bellows. The motion of the

bellows is controlled by a negative rate snap ring.

Purpose: The scavenge oil filter differential

pressure switch measures the differential

pressure across the inlet and outlet of the

scavenge oil filter. The switch provides an indication of the impending bypass

of the oil filter to the flight deck.

Start SystemObjectives


Identify the location of the components of the start system Identify the components of the start system Identify the purpose of the components of the start system Identify the purpose of the start system Identify the operation of the start system


８３

Overview

The start system consists of the following components:

Starter Starter air valve

The components of the start system function together to provide the initial

starting torque to the engine core to start the combustion process. In this

lesson, you will learn about the location, identification, and purpose of the

components, and the operation of the start system.


The start system consists of components that are listed below.

The starter is clamped to the aft face of the AGB at the 6 o'clockposition.


８４

The starter air valve is installed aft of the air starter at the 6 o'clockposition on the AGB.

PurposeThe start system provides driving torque to the AGB. The driving torque to

the AGB accelerates the HPC rotor from rest to a sufficiently high

rotational speed to start self-sustaining combustion of fuel. The start

system also helps to motor the engine for dry and wet operation during

maintenance.

Operation On receiving the engine start signal from the flight deck, the

ECU sends an electrical signal to the starter air valve. This opens the

butterfly valve in the starter air valve and high pressure air from a ground

power unit (GPU) or an auxiliary power unit (APU), flows to the starter,

causing the gears to rotate.


８５

The rotating starter gears cause the starter output shaft to rotate, which

drives the AGB. The AGB provides driving torque to the core engine. At a

certain speed, combustion begins to occur, and engine speed increases. When

the core engine speed reaches a certain value, the starter disengages from

the AGB. The ECU stops the electrical signal to the starter air valve, thus

ending air supply to the starter.

Starter

Location: The starter is clamped to theaft face of the AGB at the 6 o'clockposition.

Identification: The starter consists of a

single-stage turbine, an output shaft,

and several bearings and gears that are

contained in a metal housing. One end of

the housing has a port for air inlet. The

other end of the housing has a port for the output shaft.


８６

Purpose: The starter supplies driving torque to turn the AGB. The starteralso drives the AGB for wet and dry engine motoring during maintenance.

Starter Air Valve

Location: The starter air valve is installed aft of the air starter at the 6o'clock position on the AGB.

Identification: The starter air valve consists ofthe following components:

Valve body assembly Actuator assembly Relief valve assembly Solenoid valve assembly Position switch assembly

Purpose: The starter air valve initiates, and later,stops the flow of pressurized air to the starter.

Ignition SystemObjectives


Identify the location of the components of the ignition system Identify the components of the ignition system Identify the purpose of the components of the ignition system Identify the purpose of the ignition system Identify the operation of the ignition system

Overview

The ignition system consists of the following components:

Ignition exciters Ignition leads Igniters


８７

In this lesson, you will learn about the location, identification, and purposeof the components, and operation of the ignition system.

Location Left Side ViewThe ignition system consists of the components that are listed below.

The ignition exciters are installed on the aft fan case at the 8 o'clockposition.

The ignition leads begin from the ignition exciters on the aft fan case,and go down to the 6 o'clock position on it. The leads now pass to theHMU along the right side of the core module. Finally, the leadsconnect to the igniters on the compressor rear frame (CRF).

Location Right Side ViewThe ignition system consists of the components that are listed below.

The igniters are installed on the right side of the compressor rearframe at the 3:30 and 5 o'clock positions.


８８

PurposeThe ignition system supplies the electrical spark required for combustion of

the fuel/air mixture during the starting operation and for continuous

ignition operation.

OperationThe aircraft electrical system supplies 115-volt, AC power signal to the ECU.

The ECU sends this electrical signal to the ignition exciters. The ignition

exciters now convert AC power to DC, and send high voltage current to the

igniters through the ignition leads.

Ignition Exciters

Location: The ignition exciters

are installed on the aft fan case

at the 8 o'clock position.

Identification: The engine

contains two ignition exciters,

'A' and 'B'. Each exciter

consists of an aluminum case,


８９

which contains electrical circuits. Each sealed case is pressurized with dry

air. An input electrical connector provides power from the ECU to the

exciter. An output electrical connector transmits power from the exciter to

the igniter plugs through the ignition leads.

Purpose: The exciters convert 115-volt AC current received from the ECU

to 14,000 to 18,000-volt DC output. This DC output is then supplied to the

igniters at a rate of approximately one electrical pulse per second.

Ignition Leads

Location: The ignition leads begin from

the ignition exciters on the aft fan case,

going down to the 6 o'clock position on it.

The leads then pass by the HMU along the

right side of the core module. Finally, the

leads connect to the igniters on the compressor rear frame (CRF).

Identification: There are two ignition leads. Each lead consists of an

insulated wire in a sealed flexible conduit, which has a copper inner braid and

a nickel outer braid. The aft ends of the leads allow fan discharge air to

pass through the conduit for cooling.

Purpose: The ignition leads deliver high voltage, low current electricalsignals from the ignition exciters to the igniters.


９０

Igniters

Location: The igniters are installed on the right side ofthe CRF at the 3:30 and 5 o'clock positions.

Identification: There are two igniters. Each igniter

consists of a center electrode that is insulated from the

outer shell. When installed, the tip of this electrode

extends through ferrules into the outer liner of the

combustion chamber.

Purpose: The igniters provide electrical sparks to startcombustion.

IDG oil Cooling System

ObjectivesGiven an objective exercise, you will be able to:

Identify the location of the components of the IDG oil cooling system Identify the components of the IDG oil cooling system Identify the purpose of the components of the IDG oil cooling system Identify the purpose of the IDG oil cooling system Identify the operation of the IDG oil cooling system

OverviewThe integrated drive generator (IDG) oil cooling system consists of thefollowing components:

IDG air/oil cooler IDG air/oil cooler shutoff valve IDG fuel/oil heat exchanger

In this lesson, you will learn about the location, identification, and purposeof the components, and operation of the IDG oil cooling system.


９１

Location Right Side ViewThe components of the IDG oil cooling system are listed below.

The IDG air/oil cooler is installed on a bracket on the right side of thehigh pressure compressor (HPC) at the 3 o'clock position.

The IDG air/oil cooler shutoff valve is installed on a bracket on theright side of the HPC at the 3 o'clock position.

The IDG fuel/oil heat exchanger is installed on the right side of theaccessory gearbox (AGB), just below the servo fuel heater.


９２

PurposeThe IDG air/oil cooling system helps to cool the heated IDG oil flowingthrough the IDG.

OperationHot oil in the IDG flows to the IDG air/oil cooler, where the oil is cooled by

fan discharge air that blows in through the IDG air/oil cooler shutoff valve.

The oil then enters the IDG fuel/oil heat exchanger where the oil is further

cooled by the fuel flowing through the IDG fuel/oil heat exchanger.

IDG Air/Oil CoolerLocation: The IDG air/oil cooler is installed on a

bracket on the right side of the high pressure

compressor (HPC) at the 3 o'clock position.

Identification: The IDG air/oil cooler is a tube-

and-fin type heat exchanger. The IDG air/oil

cooler consists of tubes that are surrounded by

cooling fins. The cooler has inlets for air and oil,

and an outlet for the oil.


９３

Purpose: The IDG air/oil cooler provides cooling of the IDG oil that flows

through the IDG air/oil cooler.

IDG Air/Oil Cooler Shutoff ValveLocation: The IDG air/oil cooler shutoff valve is installed on a bracket on

the right side of the HPC at the 3 o'clock position.

Identification: The IDG air/oil cooler shutoff valve consists of a butterfly

valve and has an inlet connection for the 11th

stage muscle air and an electrical connection

for the ECU cable.

Purpose: The IDG air/oil cooler shutoff valve

controls the flow of air through the IDG

air/oil cooler.

IDG Fuel/Oil Heat ExchangerLocation: The IDG fuel/oil heatexchanger is installed on the right sideof the accessory gearbox (AGB), justbelow the servo fuel heater.Identification: The IDG fuel/oil heat

exchanger consists of a number of

metallic tubes that are enclosed in a

rectangular metal box. The box

contains baffles and chambers, and has

an inlet port and an outlet port.


９４

Purpose: The IDG fuel/oil heat exchanger cools the IDG oil that flows

through the tubes of the heat exchanger.

Vibration Monitoring SystemObjectives


Identify the location of the components of the vibration monitoringsystem

Identify the components of the vibration monitoring system Identify the purpose of the components of the vibration monitoring

system Identify the purpose of the vibration monitoring system Identify the operation of the vibration monitoring system

Overview

The vibration monitoring system consists of the following components:

No. 1 bearing accelerometer CRF accelerometer Remote charge converter

In this lesson, you will learn about the location, identification, and purposeof the components, and the operation of the vibration monitoring system.


The components of the vibration monitoring system are listed below.

The No. 1 bearing accelerometer, also called the fan vibration sensor,is installed in the A-sump. The No. 1 bearing accelerometer is boltedto the No. 1 bearing housing at the 6 o'clock position. Theaccelerometer lead extends through the fan frame strut at the 7o'clock position.


９５

The CRF accelerometer, also called the N2 vibration sensor, isinstalled on the CRF forward flange at the 10 o'clock position. Theaccelerometer lead extends to a bracket on the HPC stator case atthe 11 o'clock position.

Location Right Side ViewThe vibration monitoring system consists of components that are listedbelow.

The remote charge converter (RCC) is installed on the aft fan case atthe 5 o'clock position.


９６

PurposeThe vibration monitoring system senses the engine vibration levels andprovides the flight deck with an indication of an abnormal engine operation.

OperationThe No.1 bearing accelerometer and the CRF accelerometer sense the

vibrations around their installed locations and send indications to the RCC as

analog inputs. The RCC amplifies these weak signals and sends them to the

engine interface and vibration monitoring unit (EIVMU). The EIVMU then

converts the analog signals to digital output and sends them to the flight

deck for display on the system display (SD).


９７

No. 1 Bearing Accelerometer

Location: The No. 1 bearing accelerometer, also called the fan vibration

sensor, is installed in the A-sump. It is bolted to the

No. 1 bearing housing at the 6 o'clock position. The

accelerometer lead extends through the fan frame

strut at the 7 o'clock position.

Identification: The No. 1 bearing accelerometer

consists of a pickup, an electrical lead, and a

connector.

Purpose: The No. 1 bearing accelerometer senses

the vibration levels in the areas around the fan rotor and the LPT rotor.

CRF AccelerometerLocation: The CRF accelerometer, also called the N2 vibration sensor, is

installed on the CRF forward flange at the 10 o'clock position. The

accelerometer lead extends to a bracket on the HPC stator case at the 11

o'clock position.

Identification: The CRF accelerometer consists of a pickup, an electrical

lead, and a connector.

Purpose: The CRF accelerometer

senses the vibration levels in the

areas around the HPC rotor and

the HPT rotor.


９８

Remote Charge Converter

Location: The remote charge converter (RCC) is installed on the aft fancase at the 5 o'clock position.

Identification: The RCC consists of two

identical processing channels with associated

circuitry, and three electrical connectors.

Purpose: The RCC amplifies the weak vibration

signals received from the No. 1 bearing

accelerometer and the CRF accelerometer

before transmitting them to the EIVMU.

Drain SystemObjectivesGiven an objective exercise, you will be able to:

Identify the location of the components of the drain system Identify the components of the drain system Identify the purpose of the components of the drain system Identify the purpose of the drain system Identify the operation of the drain system

OverviewThe drain system consists of the following components:

Drain tubes Drain mast

In this lesson, you will learn about the location, identification, and purpose

of the components, and the operation of the drain system.


９９

Location Left Side ViewThe drain system consists of components that are listed below.

The drain mast is installed at the 6 o'clock position at the end of thetube bundle.

The drain tubes originate from different locations on the engine, fromthe accessories, and the pylon drain cavities. The drain tubes convergeat the 6 o'clock position on the engine to form the tube bundle, or godirectly overboard through the nacelle.


１００

PurposeThe drain system collects and carries overboard all toxic and flammable

fluids and vapors that accumulate in the nacelle and engine cavities through

outlets in the nacelle.

Operation

The drain tubes collect leaking or overflowing fluids and vapors from

different locations. These locations are the fuel manifold, the pylon, the

IDG, the starter, the hydraulic pumps, the HMU, the HPTACC, the LPTACC,

the VSV, and the VBV. The collected fluids and

vapors are then transported overboard through

openings in the nacelle.

Drain Tubes

Location: The drain tubes originate from different

locations on the engine, the accessories, and the

pylon drain cavities. The drain tubes converge at the


１０１

6 o'clock position on the engine to form the tube bundle at the drain mast,

or go directly overboard through openings in the nacelle.

Identification: The drain tubes consist of a series of tubes.

Purpose: The drain tubes collect and carry overboard all overflowing or

leaking fluids and vapors from the engine, the accessories, and the pylon

drain cavities.

Drain Mast

Location: The drain mast is installed at

the 6 o'clock position at the end of the

tube bundle.

Identification: The drain mast is bolted

to the lower portion of the bifurcation

and comes out through the thrust reverser cowl doors.

Purpose: The drain mast provides a centralized collection point from where

fluids and vapors that are transported by the drain tubes are directed

overboard.

3 engine system

Documents