ATA 49 APU (APIC)

A319/A320/A321TECHNICAL TRAINING MANUAL

MECHANICS / ELECTRICS & AVIONICS COURSE

49 APU (APIC)

This document must be used for training purpose only

Under no circumstances should this document be used as a reference.

It will not be updated.

All rights reserved.No part of this manual may be reproduced in any form,

by photostat, microfilm, retrieval system, or any other means,without the prior written permission of Airbus Industrie.

** APU Presentation (1) 1..........................

** APU Controls Presentation (1) 7.................

** APU ECAM Page Presentation (1) 13...............

** APU Installation Presentation (2) 21...........

APU Drain System Presentation (2) 29...............

APU Basic Description (3) 33.......................

** APU Fuel Feed System D/O (3) 43.................

** APU Ignition and Starting D/O (3) 47...........

** Fuel System Description/Operation (3) 51.......

** Oil System Description/Operation (3) 57........

** Air System Description/Operation (3) 63........

** APU System Management (3) 69....................

APU Warnings (3) 77.................................

** ECB Interfaces (3) 81............................

** Fuel System Components (3) 85...................

** Oil System Components (3) 99....................

** Air System Components (3) 119...................

** Miscellaneous System Components (3) 133........

MAINTENANCE PRACTICES** COMPT Access Doors Operation (2) 151...........** APU Removal / Installation (3) 155.............SPECIFIC PAGES** CFDS Specific Page Presentation (3) 165......

_A319/A320/A321 TECHNICAL TRAINING MANUAL 49 APU (APIC)MECHANICS / ELECTRICS & AVIONICS COURSE

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49 APU (APIC)

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49 - APU

49-00-00 APU PRESENTATION

CONTENTS:GeneralEngineOilFuelAirIgnition and StartingControl and MonitoringAC GeneratorSelf Examination

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APU PRESENTATION

GENERAL

The APU, installed in the fuselage tail cone in a fireproof compartment, is an independent source ofpneumatic and electrical power.It can be used in flight and on ground.The compressed air is used to supply the :

- Environmental Control System (ECS).- Main Engine Start (MES).- Anti icing.

The APU is a Model APS 3200 manufactured and designedby Auxiliary Power International Corps (APIC).

ENGINE

The APU is a single spool gas turbine engine whichdrives a load compressor and an accessory gearbox.The engine is composed of:

- a single stage centrifugal compressor.- a reverse flow combustion chamber.- a two stage axial flow turbine.

The combustion chamber is equipped with 9 fuel nozzlesand two ignitor plugs.

OIL

The Oil system is monitored by the Electronic ControlBox which receives temperature, pressure and quantitysignalsThe self contained oil system lubricates, cleans andcools the APU bearings and accessory gearbox with thesame oil types as approved for the main engines.The oil is also used to cool and lubricate the gearboxmounted AC generator.

FUEL

The APU is supplied with fuel from either the fuelfeed system pump or the fuel tank pumps, according tothe pressure sensed in the APU fuel feed line. TheFuel Control Unit (FCU) is the main component of thefuel system.The Electronic Control Box (ECB) computes the fuel/airratio, corresponding to the APU load, and meters thefuel flow accordingly. Fuel pressure is also used asmuscle pressure to operate the load compressor InletGuide Vane (IGV) actuator and the Bleed Control Valve(BCV).

AIR

The main role of the air system is to supply bleed airto the pneumatic system while avoiding compressorsurge.The air system includes a Bleed Control Valve, InletGuide Vanes to control the airflow into the loadcompressor in order to avoid overtemperature of thepower section. Control and operation of thesecomponents are assumed by the Electronic Control Box.

IGNITION AND STARTING

The APU start sequence is initiated from the cockpitand is controlled by the Electronic Control Box.During starting, the electrical starter motor drivesthe APU rotating assembly through a clutch and thegear train in the gearbox, it disengages at 55% speed.Initial combustion is ensured by the ignition Unit andthe ignitors.T

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APU PRESENTATIONTMUAPAB01-P01 LEVEL 1



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APU PRESENTATION

CONTROL AND MONITORING

The APU engine control system has manual and automaticcontrols to start, shutdown and keep the APU in safelimits during operation.The Electronic Control Box (ECB) which controls andmonitors the APU operation, is of the Full AuthorityDigital Electronic Controller (FADEC) type.The ECB has built in test equipment used for the powerup test and the monitoring test.The ECB also acts as interface between the aircraftand the APU.The ECB receives the APU Data and sends main parametersto the ECAM system.The parameters and the indications displayed on theAPU ECAM page are:

- Speed(N) and Exhaust Gas Temperature(EGT).- Bleed pressure, Inlet flap position, Low Oillevel and low fuel pressure.

- The APU AC Generator load, voltage andfrequency, through the electrical power system.

AC GENERATOR

An oil cooled APU Generator (90 KVA) can supply theaircraft electrical network.The APU AC generator, driven by the accessory gearbox, uses the APU shaft power to transform mechanicalpower into electrical power which is used by theaircraft systems.

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TMUAPAB01-P02 LEVEL 1

APU PRESENTATION



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SELF EXAMINATION

What is the main function of the APU ? A - To produce independent pneumatic and

hydraulic power. B - To produce independent pneumatic and

electrical power. C - To produce independent electrical and

hydraulic power.

Which component controls and monitors the APU ? A - The Electronic Control Box. B - The Fuel Control Unit. C - The IGV Control Unit.

The Electronic Control Box has : A - Restricted authority over APU operation. B - Only APU monitoring function. C - Full authority over APU operation.

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49 - APU

49-60-00 APU CONTROLS PRESENTATION

CONTENTS:GeneralOverhead PanelExternal Power Control PanelSelf Examination

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APU CONTROLS PRESENTATION

GENERAL

Normal control of the APU is carried out from theAPU control panel located in the cockpit. Emergencyshut down can be performed on ground from outside theaircraft.

OVERHEAD PANEL

MASTER SWITCHThe master switch pushbutton when pressed in, controlsthe power supply for APU operation and protection.A normal shutdown sequence is initiated when themaster switch is released out.The ON light comes on blue when the Master switch P/Bis pressed in and the APU page appears on the ECAMsystem display.The FAULT light comes on amber and the correspondingwarnings are activated when an automatic shutdownoccurs.

START PUSHBUTTONThe start pushbutton initiates the APU start sequence.The ON light comes on blue until 95% N(RPM).The AVAIL light comes on green above 95% N(RPM).

APU FIRE PUSH BUTTONWhen the APU fire pushbutton is released out, an APUemergency shutdown is initiated.

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APU CONTROLS PRESENTATIONTMUAPA401-P01 LEVEL 1



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EXTERNAL POWER CONTROL PANEL

APU SHUT OFF PUSHBUTTONAn APU emergency shutdown can be performed using theAPU SHUT OFF pushbutton located on the externalpower control panel, next to the nose landing gear.Operation of the APU SHUT OFF pushbutton cancels theground horn.

APU FIRE LIGHTThe APU FIRE red light comes on when a fire is detectedon ground and is accompanied by the ground horn. (APUshutdown and Auto extinguishing in this case).




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SELF EXAMINATION

From where can an APU emergency shutdown beperformed ?

A - Refuel/defuel panel,external controlpanel and cockpit.

B - APU Fire panel, external power controlpanel.

C - The APU cannot be shutdown from outsidethe aircraft.

Normal APU shutdown is performed from ?A - Fire panel.B - External power control panel.C - APU control panel.

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49 - AUXILIARY POWER UNIT

49-70-00 APU ECAM PAGE PRESENTATION

CONTENTS:GeneralExhaust Gas Temperature (EGT)SpeedFlap Open AvailableAPU GeneratorAPU BleedFuel Low PressureLow Oil Level

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APU ECAM PAGE PRESENTATION

GENERAL

The APU indications are displayed on the lower ECAMpage.This page is called manually or automatically duringAPU start.

EXHAUST GAS TEMPERATURE (EGT)

The Exhaust Gas Temperature is displayed green innormal configuration . This includes the pointer symboland digital indication.It pulses in advisory mode.It becomes red in case of over-temperature.A movable red line is computed by the ECB.The red EGTlimit value is different during APU starting and whenAPU becomes available.

SPEED

The speed indication is displayed in green.It becomes amber or red in case of overspeed.

FLAP OPEN

The green FLAP OPEN indication is displayed when theair intake flap is fully open.No indication is displayed otherwise.

- FLAP OPEN displayed steady: Air intake flapfully open with the MASTER SW pushbutton setto ON.

- FLAP OPEN displayed pulsing: Air intake flapnot fully closed 3 minutes after the MASTER SWpushbutton has been set to OFF.

AVAIL

When the APU is running, a green APU AVAILableindication appears on the upper ECAM page.The green AVAILable indication is displayed whenthe APU speed is above 95%.Nothing is displayed otherwise.




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APU GENERATOR

The APU electrical generator output is displayed asshown on the picture.The APU generator parameters are displayed amber incase of overload, or if voltage or frequency are outof range.




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APU BLEED

The APU BLEED indication is displayed in green on theupper ECAM memo page during APU BLEED supply .The APU bleed pressure indication is replaced by ambercrosses when the indication is not available.

FUEL LOW PRESS.

The FUEL LOw PRessure indication is displayed when thepressure upstream from the fuel control unit is toolow.

- The amber FUEL LO PR message is displayed whenthe fuel pressure,in the APU fuel feed line,isbelow 15 PSI.

LOW OIL LEVEL

The green LOW OIL LEVEL indication pulses when the oilin the gearbox reaches the low level and needsservicing.

- If the oil quantity decreases below 4 litres, the indication pulses on the APUECAM page.




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49-10-00 APU INSTALLATION PRESENTATION

CONTENTS:GeneralMountsAir Intake FlapAir Intake DuctExhaustAccess DoorsDrain SystemSelf Examination

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APU INSTALLATION PRESENTATION

GENERAL

The Auxiliary Power Unit is installed in a fireproofcompartment located in the fuselage tail cone.

MOUNTS

Seven tie rods attach the APU to the stucture bracketson the APU compartment ceiling.These tie rods alsoconnect to the APU three point mounted suspensionsystem.Vibration insulators are installed between the APUmount brackets and the tie rods to reduce thetransmission of aircraft vibrations and shocks to theAPU.The insulators also prevent the transmission ofvibrations from the APU to the aircraft structure.

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APU INSTALLATION PRESENTATIONTMUAPAM01-P01 LEVEL 2



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AIR INTAKE FLAP

The air intake system ducts ambient air to the APUplenum chamber.An air intake flap cuts off the air supply when theAPU does not operate.In case of failure, the air intake flap can be openedor closed manually by a Manual Override Device.A fixed diverter increases the ram air recovery forflight operation and also prevents any fluids,flowingalong the fuselage, from entering the air intake.

AIR INTAKE DUCT

The air intake duct, which is composed of a diffuserand elbow, provides correct airflow to the APU plenum.The air intake duct is attached to the right accessdoor.

EXHAUST

The exhaust system lets the APU exhaust gas flow intothe atmosphere and muffles the noise from the exhaust.The exhaust muffler thermal insulation protects theaircraft structure.




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ACCESS DOORS

Two access doors allow access to the APU compartment.The access doors on the bottom of the tailcone openoutwards to permit the APU to be inspected, lifted andlowered.

DRAIN SYSTEM

A drain system prevents the collection of fluids inthe APU compartment.Any fluid that may accumulate in the APU compartmentis delivered to a drain tank in the APU compartment,which is emptied through a drain mast when the aircraftis above 200 KTS.




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SELF EXAMINATION

On ground, in case of failure, how can you open orclose the air intake flap ?

A - The air intake flap actuator cannot beoveridden.

B - The air intake flap actuator can behydraulically overidden.

C - The air intake flap actuator can beoveridden by a Manual Override Device.

When is the drain tank emptied ?A - When the aircraft speed is above 200KTS. B - When the aircraft is stopped on the ramp.C - When the aircraft altitude is above 2000

feet.

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49-17-00 APU DRAIN SYSTEM PRESENTATION

CONTENTS:Fuel/Oil Pump Seal DrainBleed Control Valve Actuator DrainInlet Guide Vane Actuator DrainForward Bearing Seal DrainStart Fuel Manifold PurgeAir Bypass Plenum DrainExhaust Muffler DrainCombustion Chamber DrainDrain TankSelf Examination

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APU DRAIN SYSTEM PRESENTATION

FUEL/OIL PUMP DRAIN

The fuel and oil pump seal drain line is routed via acollector line to the drain tank.This line drains fuel or oil leaks.

BLEED CONTROL VALVE ACTUATOR DRAIN

The Bleed Control Valve (BCV) actuator drain line isrouted via a collector line to the drain tank. Thisline drains only fuel leaks.

INLET GUIDE VANE ACTUATOR DRAIN

The Inlet Guide Vane (IGV) actuator drain line isrouted via a collector line to the drain tank. Thisline drains only fuel leaks.

FORWARD BEARING SEAL DRAIN

Any oil leak, from the forward bearing seal, flows tothe aircraft drain mast.

START FUEL MANIFOLD PURGE

The fuel which remains in the pilot injector andmanifold is purged to the APU exhaust diffuser.

AIR BYPASS PLENUM DRAIN

The air bypass plenum drain line is routed alone tothe drain mast.This drain line collects fuel or air leaks.

EXHAUST MUFFLER DRAIN

The exhaust muffler drain line is routed to the drainmast.This drain line collects fuel, water or air leaks.

COMBUSTION CHAMBER DRAIN

The combustion chamber drain line is routed to thedrain mast. This drain line collects unburnt fuel.

DRAIN TANK

For venting and evacuation the drain tank is connectedto the drain mast.Airflow across the drain mast creates a vacuum in thedrain line. The suction effect produced at 200 kt, issufficient to remove the contents of the drain tank.A vent line ventilates the drain tank and drain lines.The APU drain lines are connected to the right accessdoor drain lines through spring adapter seals (kissseals).

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APU DRAIN SYSTEM PRESENTATIONTMUAPAG01-P01 LEVEL 2



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SELF EXAMINATION

Which drains collect fuel, water and air ?A - Exhaust coupling drain.B - Flow divider drain.C - Air bypass plenum drain.

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49 - APU

49-20-00 APU BASIC DESCRIPTION

CONTENTS:GeneralAir IntakeEngine ControlsEngineInlet guide vanesBleed and Surge AirOil SystemIgnition and StartingAccessory GearboxAC GeneratorFuel SystemSelf examination

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APU BASIC DESCRIPTION

GENERAL

The APU powerplant is installed in the fuselagetailcone. Tie rods attach the unit by a three-pointmounted suspension system to structure brackets on thecompartment ceiling in a fireproof compartment.A pair of access doors on the bottom of the tailconeopen outwards to permit the APU to be lifted andlowered.

AIR INTAKE SYSTEM

The air intake system ducts ambient air to the APUcompressor inlet.The air intake system includes :

- A fixed diverter which increases ram airrecovery for flight operation and also preventsany fluids, flowing along the fuselage, fromentering the air intake.

- An air intake with inlet flap.- An air inlet duct.




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ENGINE CONTROLS

The Electronic Control Box (ECB) controls and monitorsthe APU operation. It is a full authority digitalelectronic controller (FADEC TYPE).The ECB has the following functions :

- control of the APU start sequence,- monitoring of the APU speed, exhaust gastemperature and bleed air supply,

- normal stop sequence and automatic emergencyshutdown malfunction indications for troubleshooting.

ENGINE

The APU is a single spool engine based on a modulardesign including a single shaft power section, drivinga single stage centrifugal load compressor and anaccessory gearbox.The APU is a single shaft assembly with :

- a single stage centrifugal compressor,- a reverse flow combustion chamber,- a two stage axial flow turbine.

INLET GUIDE VANES (IGV)

The Inlet Guide Vane assembly controls the amount ofair bled from the APU load compressor.The 24 Inlet Guide Vanes are moved simultaneously bya gear train operated by an actuator.The IGV system uses fuel as hydraulic fluid for theservovalve actuator to control the Inlet Guide Vanesthrough the ECB.

BLEED AND SURGE AIR

The bleed and surge air system provides air to theaircraft pneumatic system while avoiding loadcompressor surge.The Bleed Control Valve acts as a bleed and surgevalve, electrically controlled by the ECB and fueloperated.

OIL SYSTEM

A wet sump lubrication system cools and lubricatesthe electrical generator, the accessory gearbox andthe APU bearings.The system components are all located on thegearbox except the oil cooler which is located onthe APU left hand side.

IGNITION AND STARTING SYSTEM

The ignition and starting system rotates the engineto a self sustained speed. It also will start ignitionof the fuel/air mixture in the engine combustionchamber.The system includes :

- an electrical engine starter motor,- an ignition unit,- two igniter plugs.




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ACCESSORY GEARBOX

GEARBOX ASSEMBLYThe gearbox transmits the shaft power to the APUaccessories and to the APU generator which areinstalled on the gearbox pads.The gearbox is also the oil reservoir for the APUlubrication system.

ACCESSORIESThe components mounted on the accessory gearbox are :

- the Starter Motor Assembly,- the Cooling Air Fan Assembly with the PermanentMagnet Generator (PMG),

- the Oil Pump Assembly (lubrication unit),- the Fuel Control Unit,- the AC generator.

THE AC GENERATOR

The 3 phase AC generator transforms the mechanicalpower into electrical power (90 KVA) to supply theaircraft system (115V-400Hz).




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FUEL SYSTEM

The APU is supplied with fuel from either the fueltank pumps or the APU fuel feed system pump, accordingto the pressure sensed in the APU fuel feed line. TheAPU fuel system operates automatically and includes:

- an APU fuel feed pump, an APU inlet pressureswitch,

- a low Pressure Isolation Valve, - a Fuel Low Pressure switch, - a Fuel Control Unit (FCU) for fuel flowscheduling,

- a fuel line drain vent valve.




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SELF EXAMINATION

Of what kind of design is the compressor ?A - Two stage centrifugal compressor design.B - Single stage centrifugal compressor

design. C - Two stage axial compressor design.

What are the main features of the AC generator ?A - 45 KVA, 115V, 50HZ.B - 90 KVA, 28 V.C - 90 KVA, 115V, 400HZ, 3 Phases.

What are the three APU modules ?A - Compressor, combustion chamber, turbine.B - Power section, load compressor, Fuel

Control Unit.C - Power section, load compressor,

accessory drive gearbox.

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49-31-00 APU FUEL FEED SYSTEM DESCRIPTION

CONTENTS:Fuel PumpFuel LP Isolation ValveAPU Inlet Low Pressure SensorFuel Drain Vent System

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APU FUEL FEED SYSTEM DESCRIPTION

FUEL PUMP

The APU fuel pump is a centrifugal pump driven by asingle phase AC motor.This pump is controlled to run if the APU MASTER SWpushbutton is set to ON and the fuel crossfeed linepressure is not sufficient.The fuel crossfeed line pressure sensor controls theoperation of the APU fuel pump.The APU fuel pump runs as soon as the pump inletpressure is lower than 21.8 PSI.It stops when the pressure is above 23.2 PSI .

FUEL LP ISOLATION VALVE

The APU Fuel LP isolation valve is driven by two DCmotors.This valve is open as long as the MASTER SW pushbuttonis set to ON.When closed, it prevents pressurization of the APUfuel feed line and flow of fuel into a specific firezone.The APU Fuel LP isolation valve is automatically closedwhen:

- MASTER SW P/B is released out,- ECB protective shutdown occurs,- an APU shutdown occurs due to an APU fire,detected on ground,

- the APU FIRE P/B is released out (in thecockpit),

- the APU SHUT OFF P/B has been pressed on theexternal power receptacle panel.

APU INLET LOW PRESSURE SENSOR

At the inlet connection of the Fuel Control Unit , apressure sensor transmits low pressure informationthrough the ECB to the ECAM APU page.The FUEL LO PR message is displayed on the ECAM APUpage if it is selected and:

- the APU speed is greater than 7% RPM- the fuel pressure is lower than 15.8 PSI .

The ECB memorizes this information in its BITE memoryeven if the pressure increases above 17.3 PSI .

FUEL DRAIN / VENT SYSTEM

A vent APU fuel line pushbutton, located on thefirewall allows the APU fuel feed line to be purgedduring ground maintenance.As long as the pushbutton is held pressed in, the APUfuel LP isolation valve is open and the APU fuel pumpruns.A fuel drain and vent valve is installed in the APUcompartment at the fuel inlet connection to the FuelControl Unit. It permits fuel to be drained and airto be bled.




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APU FUEL FEED SYSTEM DESCRIPTIONTMUAPA301-P01 LEVEL 3



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49-40-00 APU IGNITION AND STARTINGDESCRIPTION AND OPERATION

CONTENTS :Starter ControlIgnition ControlSelf Examination

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APU IGNITION AND STARTING DESCRIPTION AND OPERATION

STARTER CONTROL

The starting system drives the APU rotor through aclutch and gearbox.When the APU speed is 55% N, the start logic of theElectronic Control Box (ECB) cuts off the supply tothe start contactor which switches off the startermotor.The timed acceleration loop of the ECB causes the APUto accelerate to governed speed.

IGNITION CONTROL

The ignition system is used to ignite and maintaincombustion during the start phase.The ignition system includes:

- An Ignition Exciter Unit.- Two ignition leads.- Two igniter plugs.

The ignition system operates between 7% and 55% n.




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APU IGNITION AND STARTING DESCRIPTION AND OPERATIONTMUAPA901-P01 LEVEL 3



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SELF EXAMINATION

Which component controls the ignition and startingoperation

A - The Electronic Control Box.B - The Ignition Exciter Unit.C - The Start Contactor.

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49 - APU

49-32-00 FUEL SYSTEM DESCRIPTION OPERATION

CONTENTS:GeneralFuel Control UnitFuel ScheduleMuscle PressureFuel Shut-OffFlow DividerFuel DistributionFuel DrainControlMonitoringSelf Examination

TMUAPAF01 LEVEL 3

EFFECTIVITY 49-32-00 Page 1Sep 30/99


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FUEL SYSTEM DESCRIPTION OPERATION

GENERAL

The fuel system provides metered fuel to sustaincombustion.Part of the fuel is used as muscle pressure to operatethe Inlet Guide Vane actuator and the surge valveactuator.

FUEL CONTROL UNIT

The Fuel Control Unit has five functions:- fuel filtering,- pressure increase, - fuel metering,- positive fuel shut-off,- fuel muscle pressure regulation.

The Fuel Control Unit is composed of a low pressurefuel pump, a filter by-pass valve with a delta Pindicator, a high pressure fuel pump with a PressureRelief Valve, a constant delta P solenoid valve, apressure regulator (for bleed/surge valve and IGVactuators), a fuel metering valve, and the 3 waysolenoid valve.

FUEL SCHEDULE

The fuel metering valve is controlled by the ElectronicControl Box through a torque motor.The ECB schedules fuel flow for start sequence, onspeed operation and shutdown sequence.The Electronic Control Box modulates the on speed fuelschedule to match the aircraft demand for bleed airand electrical power.

MUSCLE PRESSURE

Fuel muscle pressure is used to operate the BleedControl Valve (BCV) actuator (air delivery to theaircraft and air discharge to the exhaust) and theload compressor Inlet Guide Vane (IGV) actuator.Servo fuel is returned downstream to the low pressurepump outlet and upstream to the fuel filter inlet.

FUEL SHUT-OFF

The Electronic Control Box controls the fuel solenoidvalve (3 Way Solenoid Valve) for positive fuelshut-off.The valve is controlled open during the start sequenceand closed during the stop sequence.Fuel is returned between the low pressure pump outletand the fuel filter inlet.

FLOW DIVIDER

The Flow Divider and Drain Valve (FDDVA) divides thefuel between the pilot and main injectors.During the initial start sequence, only the pilotinjectors are supplied.

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FUEL DISTRIBUTION

Fuel distribution is assumed by 3 pilot and 6 mainfuel injectors.When APU start is selected, the pilot injector valveopens when fuel pressure reaches 20 psi.During normal running the two valves are in the openposition and the fuel is allowed to supply bothinjector types.

FUEL DRAIN

The fuel drain and vent valve assembly is installedin the APU compartment at the fuel inlet connectionto the FCU (drain of APU fuel feed line/bled of airfor maintenance).In the Flow Divider and Drain Valve Assembly (FDDVA)and during shutdown, as the fuel pressure decreases,the two injector valves close. The fuel remaining inthe pilot injector is purged to the exhaust bycombustion chamber pressure.An FCU drain line purges the pump shaft seal.

CONTROL

The Electronic Control Box controls the fuel systemusing several parameters.During on speed operation, the ECB uses APU speed,Exhaust Gas Temperature and aircraft demand signals.During start, it uses speed, EGT, air inlet pressureand temperature probes (P1 and T1).The Electronic Control Box acts on the fuel meteringvalve and fuel shut-off 3 way solenoid valve.

MONITORING

Contamination of the fuel system is monitored by thedifferential pressure indicator which sends a signalto the ECB.

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TMUAPAF01 LEVEL 3



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SELF EXAMINATION

The Electronic Control box acts on:A - The fuel metering valve and the 3 way

solenoid valve ?B - The fuel metering valve and the pressure

regulator ?

When APU start is selected:A - The pilot injector valve opens ?B - The main injector valve opens ?C - Both valve types open ?

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49-90-00 OIL SYSTEM DESCRIPTION OPERATION

StorageSupplyScavengeVentingControlProtectionMonitoringSelf Examination

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OIL SYSTEM DESCRIPTION

STORAGE

The sump of the APU accessory gearbox is the oilreservoir. The accessory gearbox sump contains 5.2 l (1.4 US gal)of oil.On the left side of the gearbox is located a gravityfill port with a scupper to drain spilled oil.The gearbox has :

- a fill tube for gravity filling,- an overflow drain,- a pressure fill connector,- a sight glass.

SUPPLY

The oil is drawn from the sump and pressurized by avane type pressure pump. If the pump pressure isexcessive, a pressure relief valve opens and releasesoil back to the inlet gearbox.Regulated oil passes through a cooler and a disposablefilter.The oil is then directed to the cooling fan splines,the APU spline shaft, the APU supporting bearings (Rearand front), the gearbox pinions and the electricalgenerator (AC generator and Generator spline shaft).

SCAVENGE

Oil from the electrical generator and APU rear bearingis returned to the sump by two scavenge pumps.The oil from the AC generator returns to the sumpthrough a vane type scavenge pump and a filter.

The oil from the APU rear bearing returns to the sumpthrough a gerotor scavenge pump.Oil from the gearbox pinions and the APU front bearingis scavenged by gravity.

VENTING

The air oil mist from the rear bearing is returned tothe gearbox housing through an external pipe.An air/oil separator removes the oil particules fromthe gearbox air.This oil free air is discharged in the APU exhaust.

CONTROL

The only component of the oil system controlled by theElectronic Control Box (ECB) is the de-oiling valve.The de-oiling solenoid valve is electricaly controlledopen during APU start to ensure cold start conditions,to reduce the load on the pressure pump, and duringAPU shut-down to prevent coking of the oil remainingin the bearing chambers.

PROTECTION

The Electronic Control Box protects the APU in caseof oil system malfunction. The ECB monitors oilpressure and oil temperature.If one of the oil parameters is out of range, theElectronic Control Box initiates an automatic APU shutdown without time delay.

- Gearbox high oil temp threshold : 135°C- AC generator high oil temp : 180°C- Oil low pressure : 35PSIT

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OIL SYSTEM DESCRIPTIONTMUAPAO01-P01 LEVEL 3



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OIL SYSTEM DESCRIPTION

MONITORING

The oil system is monitored to increase the APU life.Lube and scavenge filters are equipped with visualclogging indicators.The oil sump is equipped with a low level sensor todisplay maintenance information in the cockpit. Whenthe level is at the "ADD" mark (4L/1USG) the APU mustbe able to continue running for at least 60 hours.A magetic drain plug, immersed in the APU oil, enablesthe oil drainage from the sump and attracts ferrousmetal particules.Two delta P switches (one for the scavenge filter anda second for the pressure filter) inform the ElectronicControl Box about a clogging situation (Class 2 faultmessage).

TMUAPAO01-T01 LEVEL 3



UFD4200



TMUAPAO01 LEVEL 3



UFD4200


SELF EXAMINATION

What is the only component of the oil system controlledby the Electronic Control Box ?

A - The De-oiling solenoid valve.B - The low level sensor.C - The Low Oil Pressure.

How do you check the oil quantity ?A - On the ECAM OIL page, or on a sight

glass on the oil cooler, or by CFDSinterrogation.

B - On the ECAM APU page, or on a sightglass on the accessory gearbox, or byCFDS interrogation.

C - Only by CFDS interrogation and on theECAM ENGINE/WARNING page.

TMUAPAO01 LEVEL 3



UFD4200


49 - APU

49-51-00 AIR SYSTEM DESCRIPTION OPERATION

CONTENTS:Bleed SupplyBleed ControlSurge ProtectionOil CoolingCompartment CoolingGearbox PressurizationOil VentControlMonitoringSelf Examination

TMUAPAA01 LEVEL 3



UFD4200


AIR SYSTEM DESCRIPTION OPERATION

BLEED SUPPLY

Bleed air supply to the aircraft pneumatic system iscontrolled by a bleed Control valve (deliveryfunction).The fuel operated bleed Control valve is a divertervalve (either to the aircraft system or the APUexhaust).

BLEED CONTROL

The amount of air required by the pneumatic system iscontrolled by the load compressor Inlet Guide Vanes(IGV).The Inlet Guide Vanes are moved by a fuel poweredactuator.

SURGE PROTECTION

Load compressor surge protection is also ensured bythe Bleed Control valve which discharges the excessof air in the exhaust (surge function).

OIL COOLING

A gearbox driven fan draws filtered air from the inletplenum and forces it to pass through the oil cooler.After leaving the oil cooler, the air is dischargedoverboard.The cooling fan incorporates a Permanent MagnetGenerator (PMG) which provides an emergency directcurrent supply to the Electronic Control Box, shouldthe main supply fail.

COMPARTMENT COOLING

Air supplied by the fan (driven by one of the gearsof the gearbox) is also used for APU compartmentcooling.A pneumatic compartment cooling valve enables air tobe blown through a smaller duct.Natural convection ventilates the APU compartment whenthe APU is not in operation.

GEARBOX PRESSURIZATION

Pressurized air enters the gearbox during operationfrom the front bearing seal buffering system (air frompower section compressor).

OIL VENT

The gearbox is vented to the APU exhaust. The air isbled after an air/oil separator action.

TMUAPAA01-T01 LEVEL 3



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AIR SYSTEM DESCRIPTION OPERATIONTMUAPAA01-P01 LEVEL 3



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AIR SYSTEM DESCRIPTION OPERATION

CONTROL

The Electronic Control Box controls the air systemusing several parameters:

- APU inlet pressure and temperature sensor andLoad Compressor Discharge Temperature sensor

- load compressor discharge pressure sensors(total and differential pressures)

- command and feed back signals from the actuatorand the valves.

Monitoring

To help maintenance and troubleshooting, the bleedload valve is equipped with visual position indicators(Load or Surge indication).The Load Compressor Discharge Temperature sensor(LCDT) is used to calculate the bleed air flow.

TMUAPAA01-T01 LEVEL 3



UFD4200



TMUAPAA01 LEVEL 3



UFD4200


SELF EXAMINATION

Which component regulates the airflow to thepneumatic system ?

A - The bleed load valve.B - The Inlet Guide Vanes.

Which components have a visual position indicator ?A - Bleed load valve and IGV actuator.B - IGV actuator.C - Bleed load valve.

TMUAPAA01 LEVEL 3



UFD4200



49-60-00 APU SYSTEM MANAGEMENT

CONTENTS:GeneralPower upWatch and Start preparation stateStarting stateSteady stateCooldown stateNormal Shutdown Protective ShutdownEmergency ShutdownSelf Examination

TMUAPAC01 LEVEL 3



UFD4200


APU SYSTEM MANAGEMENT

GENERAL

The APU system management and control keeps the APUrotation speed constant to obtain a constant ACgenerator frequency output, protects the power unitfrom over temperature, avoids load compressor surge,controls safe APU start and eases the APU maintenance.The APU management system controls the followingsequences:

- power state- watch statestarting statesteady run statecooldown state- shutdown state

POWER UP STATE

When the APU Master Switch is set to ON, The APU fuelLow Pressure shutoff valve opens and the APU fuel pumplogic is energized.The ECB controls the opening of the air intake flapand initiates a Power Up test:

- test of OBRM, ROM checksum, RAM read/write- test of speed injection, oil level,discreteand analog outputs

WATCH AND START PREPARATION STATE

After completion of the POWER UP state, the ECBautomatically enters the WATCH state.Upon receipt of the start command, provided that thereare no prohibitive conditions and rotation speed is

less than or equal to 7% , the ECB enters the STARTPREPARATION state.

STARTING STATE

START P/B pressed + 100 mSecsWhen the START push-button has been pressed in, theECB initiates the start sequence. The receipt of astop signal at any time during the starting state leadsto a shutdown without any cooldown.The main electrical stage selected by the ECB is:

- Backup start contactor supply

BACKUP START CONTACTOR SUPPLIED +1,5 SECThe main electrical stages selected by the ECB are:

- gearbox de-oiling valve- ignition exciter control- main start contactor supply

ROTATION SPEED N > 3%The main electrical stages selected by the ECB are:

- 3 way solenoid valve for the HP fuel ON/OFFfunction,

- fuel servovalve for the fuel metering function.

ROTATION SPEED N > 5%During starting fuel flow is controlled under thefollowing programs:

- begin manifold fill algorithm- open loop fuel schedule

TMUAPAC01-T01 LEVEL 3



UFD4200


TMUAPAC01-P01 LEVEL 3

APU SYSTEM MANAGEMENT - GENERAL



UFD4200



∆ EGT > 10°C- initiate acceleration control to 100% N


- ignition exciter de energized- gearbox de-oiling valve de-energized- main start contactor de-energized

ROTATION SPEED N > 55% + 5 SECSbackup start contactor is de energized


- surge control loop activation- APU AVAILable signal activation- start in progress output de-activation- steady state speed control loop activation- enter run state

STEADY STATE

SPEED CONTROLThis function keeps the rotation speed of the APUrotating assembly constant, whatever the load applied.This is achieved by metering the fuel flow, whichvaries with the air inlet pressure and temperature.

LOAD COMPRESSOR SURGE CONTROLThis function avoids compressor surge.

This is achieved by controlling and metering theposition of the Bleed Control Valve, according to theinlet and discharge pressure signals of the loadcompressor (∆P/P ratio).If ECB detects a surge condition, the Bleed ControlValve is positioned to discharge air to exhaust.

Note 1: In case of failure, the Bleed Control Valveis fully open to discharge.

Note 2: In case of reverse flow operation, the APU isautomatically shutdown by the ECB.

EGT CONTROLThis function avoids APU overtemperature bycontrolling the Inlet Guide Vane (IGV) position.Thus, the pneumatic load is first reduced to give thepriority to the electrical load.This is achieved by metering the position of the IGVas function of EGT and the operation mode Main EngineStart or Environmental Control System.

Note 1: In case of IGV control failure, the IGVs areclosed.

Note 2: In case of high EGT, the IGVs are closed.




UFD4200


TMUAPAC01-P02 LEVEL 3




UFD4200



COOLDOWN STATE

At stop command MASTER SW Off, all loads are removed(IGV closed, Bleed Control Valve to discharge, ACgenerator excitation cut out)then the engine goes intoa 120 second cooldown cycle.This function runs the APU at a low stabilizedtemperature before normal shutdown.

NORMAL SHUTDOWN

An APU normal shutdown is initiated when the MASTERSW pushbutton is released out.If the APU bleed air is not selected, the APU shutsdown immediately.The normal shutdown signal stops the fuel supply, Thiscauses the APU to decelerate. The AVAIL indicationgoes off and the AC generator de-energizes.When the speed is less than 90 %, the gearbox de-oilsolenoid valve opens.When the speed is less than 7% RPM, the air intakeflap is controlled to fully closed.

PROTECTIVE SHUTDOWN

When the ECB is powered, it controls the APU startingand running phases. If an abnormal parameter isdetected, it initiates an immediate shutdown withouttime delay, even if APU bleed air system is used.

ECB PROTECTIVE SHUTDOWN PARAMETERS:- OVERSPEED- OVERTEMPERATURE- LOW OIL PRESSURE- HIGH OIL TEMPERATURE- START PERIOD TIMER- SENSOR FAILURE- AIR INTAKE FLAP- NO FLAME- REVERSE FLOW- NO ACCELERATION- LOSS OF DC POWER - ECB FAILURE - GENERATOR HIGH OIL TEMPERATURE - LOSS OF SPEED SENSING - IGV SHUTDOWN

EMERGENCY SHUTDOWN

The ECB initiates an Emergency shutdown when eitherthe APU FIRE pushbutton (located in the cockpit) isreleased out or when the APU SHUT OFF pushbutton(located on external power receptacle panel) ispressed.The ECB initiates an automatic Emergency shutdown whenan APU FIRE is detected on ground.The APU shuts down immediately without time delay,even if the APU bleed air system is used.




UFD4200


SELF EXAMINATION

When does the APU air intake flap open?A - As soon as the APU operates under air

load.B - As soon as ignition begins.C - As soon as MASTER SW pushbutton is set

to ON.

APU is running and APU bleed air system is in use.What happens if APU MASTER SW pushbutton isreleased out?

A - The APU shuts down after a cooling cyclehas been completed.

B - The APU shuts down immediately.C - The APU shuts down after the closure of

fuel LP shut off valve.

The starter motor assists the APU up to which speed?A - 55 % RPM.B - 40 % RPM.C - 95 % RPM.

TMUAPAC01 LEVEL 3



UFD4200



TMUAPAC01 LEVEL 3



UFD4200



49-70-00 APU WARNINGS

CONTENTS:Automatic Shut DownEmergency Shut Down

TMUAPA601 LEVEL 3



UFD4200


APU WARNINGS

AUTO SHUT DOWN

If an AUTO SHUT DOWN occurs, the aural warning sounds,the MASTER CAUT and the MASTER SW FAULT light come on.The ECAM warning page is activated and the APU ECAMpage is called automatically.AUTO SHUT DOWN when :

- Overspeed- EGT Overtemperature- Low oil pressure- High oil temperature- Start period timer- Sensor failure EGT or Low Oil Pressure switch- Air intake not open- Underspeed- No flame- Reverse flow- No acceleration- DC power lost- ECB failure- Generator High Oil Temperature- Loss of speed sensing

EMER SHUT DOWN

If an EMER SHUT DOWN occurs, the aural warning sounds,the MASTER CAUT and the MASTER SW FAULT light come on.The ECAM warning page is activated and the APU ECAMpage is called automatically.An EMER SHUT DOWN occurs when:

- The APU shut off pushbutton is pressed on theexternal power control panel

- The APU FIRE pushbutton is released out on theoverhead panel

- The automatic fire extinguishing logic istriggered on ground.




UFD4200


APU WARNINGS - AUTOMATIC SHUT DOWN & EMERGENCY SHUT DOWNTMUAPA601-P01 LEVEL 3



UFD4200



TMUAPA601 LEVEL 3



UFD4200



49-60-00 ECB INTERFACES

CONTENTS:Power SupplyMaster Switch PushbuttonAir Intake FlapStart PushbuttonBack Up and Main Start ContactorsEmergency StopLGCIU 1APU Fuel Feed SystemEIUsBMCsTSO/JARZone Controller A320/321Generator Oil Temperature SensorSDACsCFDS

TMUAPA101 LEVEL 3

EFFECTIVITY 49-60-00 Page 1Jul 31/98


UFD4200


ECB INTERFACES

POWER SUPPLY

The Electronic Control Box is electrically supplied,through the APU MAIN control relay, by at least oneof the aircraft batteries, the aircraft DC networkand/or from the 28 VDC Permanent Magnet Generator.

MASTER SWITCH PUSHBUTTON

The APU MASTER SWITCH sends a discrete supply or stopsignal to the ECB.The Electronic Control Box sends a discrete signal tothe FAULT light when an automatic shutdown occurs ora Power Up Test fails.

AIR INTAKE FLAP

The ECB receives an air intake flap open or closedposition signal and sends a power output for openingor closing the air intake flap.

START PUSHBUTTON

A discrete input signal from the START pushbuttoninitiates the starting sequences.The ECB sends a discrete signal to the ON light duringAPU start sequence.A discrete output signal to the aircraft energizes theAVAIL light in the START pushbutton when the APU speedis above 95 %.

BACK UP AND MAIN START CONTACTORS

The ECB receives a discrete input from the Main StartContactor and sends discrete outputs to the Back Upand the Main Start Contactors.

EMERGENCY STOP

A discrete input signal from the aircraft initiatesthe APU shutdown logic after the ECB has received thissignal.

LGCIU 1

The ECB receives the flight/ground discrete inputsignal from the Landing Gear Control and InterfaceUnit 1 (LGCIU 1).This signal is used for automatic shutdown inhibitionlogic and for failed sensor logic.

APU FUEL FEED SYSTEM

The ECB receives a discrete signal from the APU LowFuel Pressure Switch.It sends a discrete signal to theAPU Fuel LP Shut OffValve.




UFD4200



ECB INTERFACES



UFD4200


ECB INTERFACES

EIUs

During engine starts, the ECB receives a Main EngineStart signal from Engine Interface Units 1 or 2.This signal causes the ECB to position the Inlet GuideVanes to fully open and the Bleed Control Valve tomodulate in delivery position.

BMCs

When the APU bleed pushbutton is set to ON, BMC 1 or2 sends a discrete input to the ECB which controlsthe opening of the APU Bleed Control Valve.

TSO/JAR

The ECB receives a discrete input from the aircraftsignature PIN programmingThis open or ground signal determines whether the ECBfollows the Technical Standard Order (TSO) or the JointAirworthiness Requirements (JAR).

ZONE CONTROLLER

The ECB receives, via an ARINC 429 bus, an input fromthe Zone Controller to control the IGV and the BleedControl Valve position according to the demand.The ECB sends a discrete output to the Zone Controllerto signal that the APU bleed control valve is indelivery position.

A320/321

The ECB receives a discrete input from the aircraftsignature PIN programmingThis identification PIN allows the ECB to identifyA321 applications for functional differences fromthose of an A320.

GENERATOR OIL TEMPERATURE SENSOR

The ECB receives an analog input from this sensor whichis an aircraft supplied component mounted on the ACgenerator.

SDACs

The ECB sends to SDACs 1 and 2, via ARINC 429 Databuses, the indications to be displayed on the ECAM APUpage and shutdown information to trigger thecorresponding warnings.

CFDS

The ECB is a type 1 computer and is connected to theCentralized Fault Display System via ARINC 429 Databuses.




UFD4200



49-30-00 APU FUEL SYSTEM COMPONENTS

CONTENTS:Fuel Control Unit LP Filter Servo Valve Fuel Nozzles Fuel Divider and Drain Valve Assembly (FDDVA)Case Drain Valve

TMUAPAV02 LEVEL 3



UFD4200


APU FUEL SYSTEM COMPONENTS

FUEL CONTROL UNIT

IDENTIFICATIONFIN: 4005 KM2

LOCATIONZONE: 315

COMPONENT DESCRIPTION

The FCU is mounted by a V band clamp on the front faceof the gearbox.

The control and metering section includes :- a constant delta P valve which controls thedifferential pressure accross the servovalve,

- a 3 way solenoid valve.

The pump section includes :- a low pressure pump,- a low pressure filter,- a high pressure pump provided with apressure relief valve.

TMUAPAV02-T01 LEVEL 3



UFD4200


APU FUEL SYSTEM COMPONENTS - FUEL CONTROL UNITTMUAPAV02-P01 LEVEL 3



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FUEL CONTROL UNIT - LP FILTER

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe inlet section includes :

- an inlet fuel filter.- a filter bypass valve.- an inlet filter differential pressureindicator.




UFD4200


APU FUEL SYSTEM COMPONENTS - LP FILTERTMUAPAV02-P02 LEVEL 3



UFD4200



FUEL CONTROL UNIT - SERVO VALVE

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe control and metering section includes :

- a Servo Valve.




UFD4200


APU FUEL SYSTEM COMPONENTS - SERVO VALVETMUAPAV02-P03 LEVEL 3



UFD4200



FUEL NOZZLES

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe 3 pilot fuel injectors spray the fuel into thecombustion chamber to permit starting.They also remain in operation during normal runningto prevent coking.The 6 main injectors spray the fuel into the combustionchamber.




UFD4200


APU FUEL SYSTEM COMPONENTS - FUEL NOZZLESTMUAPAV02-P04 LEVEL 3



UFD4200



FUEL DIVIDER AND DRAIN VALVE ASSEMBLY (FDDVA)


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe Fuel Divider and Drain Valve Assembly contains :

- a fuel filter element.- a pilot injector and purge valve.- a secondary drain valve.- a main injector valve.




UFD4200


APU FUEL SYSTEM COMPONENTS - FUEL DIVIDER AND DRAIN VALVE ASSEMBLY (FDDVA)TMUAPAV02-P05 LEVEL 3



UFD4200



CASE DRAIN VALVE

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONA combustion chamber case drain valve is provided todrain fuel that may accumulate in the combustor andthe plenum following an unsuccessful light up.




UFD4200


APU FUEL SYSTEM COMPONENTS - CASE DRAIN VALVETMUAPAV02-P06 LEVEL 3



UFD4200



TMUAPAV02 LEVEL 3



UFD4200



49-90-00 APU OIL SYSTEM COMPONENTS

CONTENTSLubrication UnitDrain PlugOil Level SensorDe-oil ValveOil Cooler AssemblyLow Oil Pressure switchHigh Oil Temperature switchOil FiltersOil Ports

TMUAPAT01 LEVEL 3

EFFECTIVITY 49-90-00 Page 1Jun 30/00


UFD4200


APU OIL SYSTEM COMPONENTS

LUBRICATION UNIT


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe oil sump assembly is formed by the lower part ofthe gearbox.One pressure pump and two scavenge pumps are drivenby the gearbox.

TMUAPAT01-T01 LEVEL 3



UFD4200


TMUAPAT01-P01 LEVEL 3

APU OIL SYSTEM COMPONENTS - LUBRICATION UNIT



UFD4200



DRAIN PLUG

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe drain plug contains a chip detector.When the chip detector is removed, a check valveprevents oil loss.




UFD4200



APU OIL SYSTEM COMPONENTS - DRAIN PLUG



UFD4200



OIL LEVEL SENSOR

IDENTIFICATIONFIN: 119 KD

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe oil level sensor is a Resistive Temperature Device.The resistance varies with the oil level and modifiesthe sensor output voltage checked by the ECB.




UFD4200



APU OIL SYSTEM COMPONENTS - OIL LEVEL SENSOR



UFD4200



DE-OIL VALVE


LOCATIONZONE: 315

COMPONENT DESCRITIONThe de-oil valve permits air to enter the suction sideof the lubrification pump to reduce the starter loadin the following conditions :

- If the oil sump temperature is below -6.7°C(20°F) during the start sequence between 0%and 60% APU speed.

- When the APU speed is between 95% and 7% ateach shutdown.

- When the altitude is more than 30,000 ft ateach start.




UFD4200



APU OIL SYSTEM COMPONENTS - DE-OIL VALVE



UFD4200



OIL COOLER ASSEMBLY


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe oil cooler includes:

- An air cooler housing which consists of anintegrally brazed aluminium heat exchanger withaluminium face flanges and stainless steel backup flanges

- A check valve and a by pass valve- A drain plug.




UFD4200


APU OIL SYSTEM COMPONENTS - OIL COOLERTMUAPAT01-P05 LEVEL 3



UFD4200



LOW OIL PRESSURE SWITCH


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe Low Oil Pressure switch contact opens to signallow oil pressure.




UFD4200


APU OIL SYSTEM COMPONENTS - LOW OIL PRESSURE TMUAPAT01-P06 LEVEL 3



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HIGH OIL TEMPERATURE SWITCH

IDENTIFICATIONFIN:120 KD

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe High Oil Temperature sensor is a resistivetemperature device.The resistance varies with the oil temperature andmodifies the sensor output voltage.




UFD4200


APU OIL SYSTEM COMPONENTS - HIGH OIL TEMPERATURE SWITCHTMUAPAT01-P07 LEVEL 3



UFD4200



OIL FILTERS

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENTS DESCRIPTIONThe 20 microns filter elements for the generator oilscavenge filter and the lubrication filter areidentical.The impending blockage indicator pops up for a ∆Phigher than 30 to 35 PSI.A bypass valve opens for a ∆P higher than 30 to 60PSI.




UFD4200



APU OIL SYSTEM COMPONENTS - OIL FILTERS



UFD4200



OIL PORTS

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENTS DESCRIPTIONWhen using the pressure fill port, do not overfill theAPU.




UFD4200



APU OIL SYSTEM COMPONENTS - OIL PORTS



UFD4200



TMUAPAT01 LEVEL 3



UFD4200



49-50-00 APU AIR SYSTEM COMPONENTS

CONTENTSBleed Control ValveInlet Guide VaneLoad Compressor Discharge Temperature SensorLoad Compressor Discharge Pressure SensorsLoad Compressor Inlet Pressure And Temperature SensorCooling Fan

TMUAPAW01 LEVEL 3



UFD4200


APU AIR SYSTEM COMPONENTS

BLEED CONTROL VALVE


LOCATIONZONE: 316

COMPONENT DESCRIPTIONThe Bleed Control Valve is located on the right lowerpart of the APU at the scroll outlet.It delivers air to the aircraft while avoiding loadcompressor surge.The valve is selected from the APU BLEED pushbuttonswitch, and controlled by the ECB.

TMUAPAW01-T01 LEVEL 3



UFD4200


APU AIR SYSTEM COMPONENTS - BLEED CONTROL VALVETMUAPAW01-P01 LEVEL 3



UFD4200



INLET GUIDE VANE SYSTEM


LOCATIONZONE: 316

COMPONENT DESCRIPTIONThe Inlet Guide Vanes and their control mechanism arelocated at the load compressor air inlet.The servo valve and actuator form an assembly locatedon the right upper part of the APU on the loadcompressor casing.




UFD4200


APU AIR SYSTEM COMPONENTS - INLET GUIDE VANETMUAPAW01-P02 LEVEL 3



UFD4200



LOAD COMPRESSOR DISCHARGE TEMPERATURE SENSOR (LCDT)


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe LCDT is located on the bleed valve inlet duct.The LCDT provides an input signal to the ECB forindication, it’s a resistance temperature device.




UFD4200


TMUAPAW01-P03 LEVEL 3

APU AIR SYSTEM COMPONENTS - LOAD COMPRESSOR DISCHARGE TEMPERATURE SENSOR (LCDT)



UFD4200



LOAD COMPRESSOR DISCHARGE PRESSURE SENSORS

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe pressure sensors are assembled together in oneunit which is located on the front of the air intakeplenum.They are made of a bridge of 4 resistors.




UFD4200


APU AIR SYSTEM COMPONENTS - LOAD COMPRESSOR DISCHARGE PRESSURE SENSORSTMUAPAW01-P04 LEVEL 3



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LOAD COMPRESSOR INLET PRESSURE AND TEMPERATURE SENSOR

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe sensor is located on the rear of the air intakeplenum.The pressure sensor is made of a bridge of 4 resistorsprinted on a flexible support, the temperature sensoris an adjustable resistor.




UFD4200



APU AIR SYSTEM COMPONENTS - LOAD COMPRESSOR INLET PRESSURE AND TEMPERATURE SENSOR



UFD4200



COOLING FAN

IDENTIFICATIONFIN:

LOCATIONZONE: 315

COMPONENT DESCRIPTION

The cooling fan incorporates a generator which providesan emergency direct current to the Electronic ControlBox.The cooling fan is located at the gearbox front face.




UFD4200



APU AIR SYSTEM COMPONENTS - COOLING FAN



UFD4200



TMUAPAW01 LEVEL 3



UFD4200



49-00-00 MISCELLANEOUS APU SYSTEMCOMPONENTS

CONTENTS:Attach RodsStarter MotorSerial Number EncoderEGT SensorSpeed SensorElectronic Control BoxDrain TankIgnition Unit

TMUAPAS01 LEVEL 3



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MISCELLANEOUS APU SYSTEM COMPONENTS

ATTACH RODS

IDENTIFICATIONFIN: 4065/4075/4085 KM

LOCATIONZONE:315/316

COMPONENT DESCRIPTIONDuring APU removal and installation, use the threadprotectors to prevent damaging the bolts.

TMUAPAS01-T01 LEVEL 3



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MISCELLANEOUS APU SYSTEM COMPONENTS - ATTACH RODSTMUAPAS01-P01 LEVEL 3



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STARTER MOTOR


LOCATIONZONE: 315/316

COMPONENT DESCRIPTIONThe starter motor is a series wound DC electric motorwith 4 poles and 4 brushes.It is equipped with a visual and an electrical brushwear indicator.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENT - STARTER MOTORTMUAPAS01-P02 LEVEL 3



UFD4200



SERIAL NUMBER ENCODER


LOCATIONZONE: 315

COMPONENT DESCRIPTIONThe engine identification module is made of resistorslocated on printed circuit board.The Electronic Control Box (ECB) automatically resetsthe cycles and hours to zero when it sees a change inAPU serial number.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - SERIAL NUMBER ENCODERTMUAPAS01-P03 LEVEL 3



UFD4200



EGT SENSOR

IDENTIFICATIONFIN: P30, P31


COMPONENT DESCRIPTIONThe thermocouples provide an electromotive force infunction of the temperature difference between the hotjunction in the exhaust gas stream and the coldjunction connected to the measuring device.The two EGT rakes (EGT sensors) are separatelyconnected and the ECB uses the higher value. In caseof failure of a rake, the ECB uses the remaining one.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - EGT SENSORTMUAPAS01-P04 LEVEL 3



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SPEED SENSOR

IDENTIFICATIONFIN: 113 KD, 112 KD


COMPONENT DESCRIPTIONThe two independent magnetic speed sensors are locatedin front of a common target phonic wheel.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - SPEED SENSORTMUAPAS01-P05 LEVEL 3



UFD4200



ELECTRONIC CONTROL BOX


LOCATIONZONE: 152

COMPONENT DESCRIPTIONThe Electronic Control Box (ECB) is a fully digitalelectronic controller that does the primary part ofthe APU system logic.It is located in the bulk cargo compartment, righthand side.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - ELECTRONIC CONTROL BOXTMUAPAS01-P06 LEVEL 3



UFD4200



DRAIN TANK

IDENTIFICATIONFIN:

LOCATIONZONE: 316

COMPONENT DESCRIPTIONThe capacity of the drain tank is three shutdowns ofthe APU when the aircraft is on the ground.After three shutdowns, the contents will automaticallydrain when the drain system tank is full.In flight, due to suction effect, it is automaticallydrained.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - DRAIN TANKTMUAPAS01-P07 LEVEL 3



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IGNITION UNIT

IDENTIFICATIONFIN: P10


COMPONENT DESCRIPTIONThe ignition exciter is a sealed metal box assemblywith a mounting bracket on one side.Power is supplied to the ignition exciter through amultipin electrical connector, the two igniter cablesconnect the two connectors to the igniters.




UFD4200


MISCELLANEOUS APU SYSTEM COMPONENTS - IGNITION UNITTMUAPAS01-P08 LEVEL 3



UFD4200



TMUAPAS01 LEVEL 3



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49-11-00 APU COMPARTMENT ACCESS DOOROPERATION

CONTENTS:Door OpeningDoor Closure

TMUAPUK01 LEVEL 3



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APU COMPARTMENT ACCESS DOOR OPERATION

DOOR OPENING

In the cockpit, open the APU circuit breakers.Position a work stand suitable to reach the aircraftunder the APU compartment.The APU doors are secured by a total of seven latches,five latches secure the left door and two latchessecure the right door.The left hand door must be opened first to gain accessto the latches for the right hand door.Start by releasing the rear latch.Next, the three latches connecting the doors togetherare undone.As each latch is undone, secure the latch hook on thelatch lever.Continue to release the remaining latches.When all latches have been released, pull the dooropen and secure with the door support strut.The strut is stowed at the forward end of the leftdoor.Release the strut pip-pin from the door, extend thetelescopic strut and secure to the aircraft using thepip-pin.Push the door open until the strut locks in the fullyextended position.This completes the opening of the left hand door.With the left hand door open, the two latches securingthe right hand door are now visible.The forward latch is released.Followed by the rear latch and the door is ready tobe opened.

Use the assist handle mounted on the air inlet ductand swing the door fully open.The door hold open mechanism incorporates acounterbalance spring that takes most of the doorweight.The door will lock automatically in the door openposition.No locking pins are necessary to secure the right handdoor in the open position.A red coloured pip-pin is provided to lock the doorhold open spring mechanism should it become necessaryto remove the door from the aircraft. In this eventthe red pip-pin should be removed from its stowage andinserted in the adjacent hole with a red surround. Toprevent injury, a placard advises against removal ofthe red coloured bolt when the access door is removed.This completes the APU door opening procedure.

CAUTION: In event of door removal you must secure theright access door hold-open device byinserting the locking pin in the locking hole.The pin is stowed next to this locking hole.

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APU COMPARTMENT ACCESS DOOR OPERATIONTMUAPUK01-P01 LEVEL 3



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APU COMPARTMENT ACCESS DOOR OPERATION

DOOR CLOSURE

To close the right hand door, apply a lifting forceto the door with one hand, and at the same time, tapthe orange coloured release handle marked "PUSH" in adownward, outward direction to release the overcentregeometric lock on the door hold open mechanism.Lift the door to the closed position, using the assisthandle on the air inlet duct.Secure the forward and rear latches on the right handdoor.The left door support strut must be stowed beforeclosing the left door.To release the lock on the left hand door supportstrut, pull down on the knurled collar. While holdingthe collar down, partially close the door.Hold the door with the left hand and with the righthand, release the door support strut pip-pin from theaircraft. Stow the support strut on the door. Closethe left door.Secure the forward latch.Ensure that the latch release lever is flush with thelatch.Secure the rear latch.Secure the three latches holding the left and rightdoors together. To secure these latches:

- Release the latch hook by pressing the latchrelease lever.

- Engage the latch hook in the locking bracket.- Close the latch lever. - Ensure that the latch release lever is flushwith the latch.

Repeat the closing procedure for the remaining latches.Carry out a final visual inspection to ensure that alllatches are secure. This completes the APU access doorclosing procedure. Finally, reset the APU circuitbreakers in the cockpit.

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49-12-00 APU REMOVAL AND INSTALLATION

CONTENTS:WarningFuel DrainElectrical Connectors 1Electrical Connectors 2PneumaticHoistingMountsSupport Frame

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APU REMOVAL AND INSTALLATION

WARNING

WARNING: Make sure that you have the correct firefighting equipment available.

WARNING: Do not touch the APU until it is sufficientlycool to prevent burns when you do themaintenance task.

WARNING: Lock the mechanism of access door 316 AR withthe pip pin when you open the access door.

WARNING: Depressurize green and yellow hydraulicsystems.

WARNING: Open, safety and tag the appropriate circuitbreakers.

NOTE: Before APU removal, on the CFDS, do the BITEtest of the APU and record the APU hours andcycles.

NOTE: After APU installation, bleed the APU fuel linebefore you start the APU (to prevent hot start).

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APU REMOVAL AND INSTALLATION - FUEL DRAINTMUAPUR01-P01 LEVEL 3



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APU REMOVAL AND INSTALLATION - ELECTRICAL CONNECTORS 1TMUAPUR01-P02 LEVEL 3



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APU REMOVAL AND INSTALLATION - ELECTRICAL CONNECTORS 2TMUAPUR01-P03 LEVEL 3



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APU REMOVAL AND INSTALLATION - PNEUMATICTMUAPUR01-P04 LEVEL 3



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APU REMOVAL AND INSTALLATION - HOISTINGTMUAPUR01-P05 LEVEL 3



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APU REMOVAL AND INSTALLATION - MOUNTSTMUAPUR01-P06 LEVEL 3



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APU REMOVAL AND INSTALLATION - SUPPORT FRAMETMUAPUR01-P07 LEVEL 3



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49 - APU

49-73-00 CFDS SPECIFIC PAGE PRESENTATION

CONTENTS:APU Data/oilPerformance SettingsShutdowns.

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EFFECTIVITY 49-73-00 Page 1Mar 31/94


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CFDS SPECIFIC PAGE PRESENTATION

APU DATA/OIL

To gain access to the SYSTEM REPORT/TEST APU MENU, theAPU MASTER SWITCH must be set to ON.The APU is a type 1 system. It is not available inCFDS back-up mode.The APU DATA/OIL page gives the :

- APU serial number- APU operating hours- APU cycles- APU oil level.

"OIL LEVEL:LOW" replaces"OIL LEVEL:OK" when the oilquantity decreases to 3.69 l (3.9 qt.).Each APU contains a serial number encoder whichprovides the information required for proper CFDSinterpretation, continuity of LRU fault history, hoursand cycles of the APU.When you replace an APU or a serial number encoder,the ECB resets the APU hours and cycles to zero. TheData Management Unit (DMU) of the Aircraft IntegratedData System (AIDS) also calculates the APU hours andcycles so that their records are not lost when an ECBis replaced.

PERFORMANCE SETTINGS

The APU Performance Settings page gives the settingsof:

- EGT trim- COOLDOWN time

Base maintenance staff cannot modify these settingswhich are programmed by adjusting the variouselectronic switches within the ECB (5 levelsavailable) following the aircraft operatingconditions.

SHUTDOWNS.

The APU SHUTDOWNS page gives the reason of the shutdown(OVERSPEED) and the related LRUs causing thefault(classed in descending probability order) .Refer to the TSM to trouble shoot the faulty componentwhich caused the shutdown.

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CFDS SPECIFIC PAGESTMUAPWY06-P01 LEVEL 3



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Documents

ATA 49 APU (APIC)