Airbus A318/A319/A320/A321 (CFM56) and AT A 49

Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

TRAINING MANUAL

Airbus A318/A319/A320/A321 (CFM56) and

Airbus A319/A320/A321 (IAE V2500) B1.1
(sub-) categories

49. APU – GARRETT GTCP 36-300

(ATA49)

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 1

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

TABLE OF CONTENTS

APU PRESENTATION ....................................................................................... 4

APU CONTROLS PRESENTATION .................................................................. 8
ECAM ENG WARNING AND STATUS PAGE ................................................. 11
APU ATT ACHMENT ......................................................................................... 16
APU REMOVAL AND INSTALLAT ION ............................................................ 18
APU COMPARTMENT ACCESS DOORS OPERATION ................................ 22
APU DRAIN SYSTEM PRESENTATION ......................................................... 24
AIR INTAKE SYSTEM ...................................................................................... 26
APU BASIC DESCRIPTION............................................................................. 32
APU IGNITION AND STARTING - DESCRIPTION AND OPERATION ......... 34
APU FUEL FEED SYSTEM DESCRIPTION ................................................... 43
APU FUEL SYSTEM DESCRIPTION .............................................................. 44
FUEL SYSTEM COMPONENTS ...................................................................... 47
APU AIR SYSTEM DESCRIPTION.................................................................. 50
AIR SYSTEM COMPONENTS ......................................................................... 52
APU SYSTEM MANAGEMENT........................................................................ 58
INDICAT ION AND MONITORING SYSTEM ................................................... 68
ENGINE CONTROL.......................................................................................... 74
ECB INTERFACES........................................................................................... 76
APU ECAM PAGE PRESENTATION............................................................... 80
APU WARNINGS.............................................................................................. 84
CFDS SPECIFIC PAGE PRESENTATION ...................................................... 88
APU OIL SYSTEM DESCRIPTION.................................................................. 90

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 2

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

IGV ACTUATOR ...............................................................................................56

TABLE OF FIGURES RUNNING SEQUENCE AIR INTAKE FLAP SEQUENCE - START
SEQUENCE.......................................................................................................59
APU PRESENTATION....................................................................................... 5 RUNNING SEQUENCE - ACCELERATION SEQUENCE ..............................61
COOLING ........................................................................................................... 6 RUNNING SEQUENCE - PNEUMATIC AND ELECTRICAL SUPPLY
APU CONTROLS PRESENTATION ................................................................. 8 NORMAL SHUTDOWN SEQUENCE - PNEUMATIC AND ELECTRICAL
APU CONTROLS PRESENTATION ................................................................. 9 SUPPLY ............................................................................................................63
APU ECAM DISPLAY ...................................................................................... 10 NORMAL SHUTDOWN SEQUENCE DECELERATION SEQUENCE -AIR
APU ECAM ENG. WARNING AND STATUS PAGE...................................... 11 INTAKE FLAP SEQUENCE .............................................................................65
CONTROLS AND INDICATIONS.................................................................... 12 PROTECTIVE SHUTDOWN - EMERGENCY SHUTDOWN............................67
WARNINGS AND CAUTIONS......................................................................... 13 RPM SPEED SENSOR DESCRIPTION...........................................................68
APU COMPARTMENT..................................................................................... 15 SPEED SENSOR ..............................................................................................69
ATTACH ROADS ............................................................................................. 16 SERIAL NUMBER ENCODER .........................................................................71
APU ATTACHMENT ........................................................................................ 17 EGT SENSOR ...................................................................................................73
HOISTING......................................................................................................... 19 ECB ...................................................................................................................75
MOUNTS .......................................................................................................... 20 ECB INTERFACES ...........................................................................................77
SUPPORT FRAME........................................................................................... 21 APU ECAM PAGE PRESENTATION ..............................................................81
APU COMPARTMENT ACCESS DOORS...................................................... 23 APU ECAM PAGE PRESENTATION ..............................................................82
APU DRAIN SYSTEM PRESENTATION ........................................................ 25 APU ECAM PAGE PRESENTATION ..............................................................83
AIR INTAKE SYSTEM LAYOUT ..................................................................... 29 AUTO SHUT DOWN .........................................................................................85
AIR INTAKE SCHEMATIC............................................................................... 31 EMER SHUT DOWN.........................................................................................87
APU BASIC DESCRIPTION ............................................................................ 33 CFDS SPECIFIC PAGES .................................................................................89
APU IGNITION AND STARTING DESCRIPTION AND OPERATION........... 35 APU OIL SYSTEM DESCRIPTION ..................................................................91
IGNITION UNIT ................................................................................................ 37 OIL SYSTEM COMPONENTS - LUBRICATION UNIT ...................................93
IGNITER PLUG/IGNITION UNIT ..................................................................... 39 DRAIN PLUG ....................................................................................................94
STARTER MOTOR .......................................................................................... 41 OIL LEVEL SENSOR........................................................................................95
APU FUEL FEED SYSTEM DESCRIPTION ................................................... 43 GENERATOR SCAVENGE PUMP ..................................................................96
APU FUEL SYSTEM DESCRIPTION.............................................................. 45 DE-OIL VALVE .................................................................................................97
FUEL CONTROL UNIT .................................................................................... 47 COOLING FAN .................................................................................................98
COMPONENTS ................................................................................................ 49 OIL COOLER ASSEMBLY...............................................................................99
APU AIR SYSTEM DESCRIPTION ................................................................. 51 LOW OIL PRESSURE / HIGH OIL TEMPERATURE SWITCHES................100
AIR SYSTEM COMPONENTS - LOAD BLEED VALVE ................................ 52 PRESSURE REGULATOR VALVE ...............................................................101
SURGE CONTROL VALVE ............................................................................. 52 OIL FILTERS...................................................................................................102
AIR SENSING ELEMENTS.............................................................................. 53 OIL PORTS .....................................................................................................103
P2 SENSOR ..................................................................................................... 53 SUMP OIL TEMPERATURE SENSOR..........................................................104
LOAD COMPRESSOR DISCHARGE TEMPERATURE SENSOR (LCDT)... 54 OIL HEATER...................................................................................................105
Load Compressor Inlet Temperature Sensor (LCIT) .................................. 54
LOAD COMPRESSOR INLET TEMPERATURE SENSOR (LCIT)................ 54
COMPONENTS ................................................................................................ 55

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 3

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU PRESENTATION

General Air

The APU is a Model GTCP 36-300 manufactured and designed by GARRET. The main role of the air system is to supply bleed air to the pneumatic
system.
The APU is an independent source of pneumatic and electrical power. It can This is supplied by the load compressor.
be used in flight and on ground. The bleed air includes a load bleed valve, a flow regulation by means of Inlet
Guide Vanes and a surge protection.
Engine Control and operation of these components are controlled by the Electronic
Control Box.
The APU is a single shaft type engine which produces the energy used to
drive the load compressor and the accessory gearbox. Ignition and Starting

The engine is composed of: The APU start sequence is initiated from the cockpit and is controlled by the
Electronic control box. During starting, the electrical starter motor drives the
a single stage centrifugal compressor. APU and initial combustion is seconded by the ignition system.
a reverse flow combustion chamber. Starter disengages when the APU is above 50% RPM.
a single stage radial inflow turbine.

The combustion chamber is equipped for the installation of 6 dual fuel

nozzles and one igniter plug.

Oil

The conditions of the Oil system is monitored by the Electronic Control Box
which receives temperature, pressure and quantity signals.
The self contained oil system lubricates, cleans and cools the APU bearings
and accessory gearbox.
The oil is also used to cool and lubricate the gearbox mounted generator.

Fuel

The Fuel Control Unit (FCU) is the main component of the fuel system.
The Electronic Control Box (ECB) computes the fuel/air ratio, corresponding
to the APU load, and meters the fuel flow accordingly.
Fuel pressure is also used as muscle pressure to operate the load
compressor Inlet Guide Vane actuator.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 4

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 5

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Bleed Valve

The bleed air delivered by the load compressor, is ducted to the aircraft
pneumatic system via the bleed load valve.

The Bleed Valve is electrically controlled and pneumatically operated. Each

Bleed Monitoring Computer (BMC) sends an opening signal to the ECB,
which energizes the bleed load valve solenoid only if the APU speed is
greater than 95% and no shutdown is initiated.

Surge Valve

The air delivered by the load compressor may be much more than the air
needed by the pneumatic system. The surge valve discharges the excess air
into the APU exhaust.

The ECB controls the surge valve via a torque motor. To avoid compressor
surge, a calculated airflow is determined according to the IGV positions. The
ECB compares the measured compressor airflow rate from Pt and DP with
the calculated airflow. The airflow difference repositions the Surge Valve.
W hen the Bleed Load Valve is open, the Surge Valve tends to close. During
Main Engine Start, the Surge Valve modulates to give a constant bleed air
pressure.

Cooling

A gearbox driven cooling fan draws the air from the inlet plenum and forces
some of it through the oil cooler. The remaining air is used for APU
compartment ventilation.

Inlet air is used for oil cooler and APU compartment cooling.

This air is drawn by a gearbox driven fan.

COOLING

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 6

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 7

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU CONTROLS PRESENTATION

General

Normal control of the APU is carried out from the APU control panel located The FAULT light comes on amber and the corresponding warnings are
in the cockpit. Emergency shut down can be performed on ground from activated when an automatic shutdown occurs.
outside the aircraft.
Start Push Button
Overhead Panel
The start push-button initiates the APU start sequence. The ON light comes
Master Switch on blue until 95%N(RPM).
The AVAIL light comes on green above 95% N (RPM).
The master switch controls the power supply for APU operation and
protection. APU Fire Push Button
A normal shutdown sequence is initiated when the master switch is released
out. W hen the APU fire push button is released out, an APU emergency
The ON light illuminates blue when the Master switch P/B is pressed and the shutdown is initiated.
APU page appears on the ECAM system display.

APU CONTROLS PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 8

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

External Power Control Panel APU Shutoff Push-button

APU Fire Light An APU emergency shutdown can be performed using the APU SHUT OFF
push button located on the external power control panel, next the nose
The APU FIRE red light comes on when a fire is detected on ground. landing gear.

Red light illumination is accompanied by the ground horn. (Auto extinguishing Operation of the APU SHUTOFF push-button cancels the external horn.
in this case).

APU CONTROLS PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 9

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU ECAM DISPLAY

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 10

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

ECAM ENG WARNING AND STATUS PAGE

APU AVAIL. STS

If APU is running the green ”APU AVAIL” Message will be displayed on the APU
MEMO page.If APU Bleed is ”ON” the Message will be ”APU BLEED”
If APU is shown on the STS-page a Class 2 Fault is present.Using the CFDS
APU Emerg. STOP or APU Auto Shut Down the fault which is stored in the ECB can be identified.

”APU EMERG STOP” is displayed in case of fire.

”APU AUTO SHUT DOW N” is displayed in case of a FAULT other than a
fire.

APU ECAM ENG. WARNING AND STATUS PAGE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 11

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

CONTROLS AND INDICATIONS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 12

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

E/W D: FAILURE TITLE LOCAL

AURAL MASTER SD PAGE FLT PHASE
W ARNING
W ARNING LIGHT CALLED INHIB
Conditions LIGHT
AUTO SHUT DOW N
Automatic shut down of APU for a reason other than a fire.
MASTER APU MASTER
EMER SHUT DOW N SINGLE CHIME APU 3. 4, 5, 7, 8
CAUTION SW FAULT
Fire detection on ground or use of APU SHUT OFF P/B on
external power control panel or APU FIRE P/B pushed.

MEMO DISPLAY

APU AVAIL message is displayed in green when APU N is above 95%.

WARNINGS AND CAUTIONS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 13

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU Compartment

The APU compartment is located in the aircraft tail section. Note: The compartment temperature is kept below 100°C (212°F) on the
ground (ISA +40°C). The APU surface temperature does not exceed 232°C
The tail cone of this section is attached to the fuselage structure and (450°F).
arranged as a support and fairing for the APU.

The compartment is arranged as a fire proof box with fire walls made of
titanium alloy.

Two longitudinally-hinged access doors also made of titanium alloy provide

access to the APU compartment.

The air inlet duct is attached to the right door to provide access for APU
removal and installation.

A pressure relief door limits the pressure in the compartment to a value which
is acceptable for the structure. The APU compartment is entirely fire proof. It
has a fire extinguishing bottle located in a separate compartment, forward of
the APU compartment.

Cooling and ventilation of the compartment is provided during APU operation

and when the APU is shutdown.

W hen the APU is in operation forced cooling and ventilation is provided by

the APU air cooling system.

The cooling is provided by the APU driven oil cooler fan. The fan provides the
air flow to the oil cooler and a flow which escapes into the APU compartment.

Refer to "air system" for more details.

W hen the APU is not operating, ventilation is achieved through a louvre in

the upper left side of the compartment. Due to the temperature difference
between the inside and outside of the compartment, ventilation is by
convection.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 14

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU COMPARTMENT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 15

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU ATT ACHMENT

The APU is provided with two lateral front mounts and one aft upper mount. Jacking

The mounts are provided with shock absorbers (silicone vibration insulators). The APU also has three jacking points: one on each side of the gearbox, and
one at the bottom of the combustor casing.
The shock mounts are designed so that the APU does not fall in the event of
the loss of a shock mount.

The attachment is designed to retain the APU in the event of the failure of
one complete mounting.

The APU is suspended in the tail section by rods:

On each of the two lateral front mounts

On the rear mount.

Aircraft on ground, the APU longitudinal axis forms an angle of approximately

6° with the horizontal axis (the APU front section is thus inclined downwards).

Front Attachment

The front attachment consists of the two lateral front mounts, one on each
side of the APU gearbox. Each front mount is connected to rods through
vibration insulators.

Rear Attachment

The rear attachment consists of the rear mount located at the rear of the
power section. The rear mount is also connected through vibration insulators.

Lifting of the APU

Lifting of the complete APU is achieved by means of a lifting eye installed on

the gearbox.

Note: The shock mounts and the rods are provided by the aircraft
ATTACH ROADS
manufacturer.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 16

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU ATTACHMENT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 17

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU REMOVAL AND INST ALLAT ION

Warning

Warning: Make sure that you have the correct fire fighting equipment
available.

Warning: Do not touch the APU until it is sufficiently cool to prevent burns
when you do the maintenance task.

Warning: Lock the mechanism of access door 316 AR with the pip pin when
you open the access door.

Warning: Depressurize green and yellow hydraulic systems.

Warning: Open, safety and tag the appropriate circuit breakers.

Note: Before APU removal, on the CFDS, do the BITE test of the APU and
record the APU hours and cycles.

Note: After APU installation, bleed the APU fuel line before you start the APU
(to prevent hot start).

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 18

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Connect the hoist to the ceiling bracket.

Connect the hoist to the left side wall.
Connect the shackle to the APU hoisting point.

HOISTING

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 19

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Slowly wind the APU hoist until the cable is in tension.

Remove the APU mount nuts.
Protect the APU mount threads.

MOUNTS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 20

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Using the mounts, attach the APU to its support frame.

SUPPORT FRAME

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 21

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU COMPARTMENT ACCESS DOORS OPERATION

Door Opening Door Closure

In the cockpit, open the APU circuit breakers. To close the right hand door, apply a lifting force to the door with one hand,
Position a work stand suitable to reach the aircraft under the APU and at the same time, tap the orange colored release handle marked 'PUSH
compartment. The APU doors are secured by a total of seven latches, five in a downward, outward direction to release the over centre geometric lock
latches secure the left door and two latches secure the right door. on the door hold open mechanism.
The left hand door must be opened first to gain access to the latches for the Lift the door to the closed position, using the assist handle on the air inlet
right hand door. duct. Secure the forward and rear latches on the right hand door.
Start by releasing the rear latch. Next the three latches connecting the doors The left door support strut must be stowed before closing the left door.To
together are undone. As each is undone, secure the latch hook on the latch release the lock on the left hand door support strut, pull down on the knurled
lever. collar.
Continue to release the remaining latches. W hen all latches have been W hile holding the collar down, partially close the door. Hold the door with the
released, pull the door open and secure with the door support strut. left hand and with the right hand, release the door support strut pip-pin from
The strut is stowed at the forward end of the left door. Release the strut pip- the aircraft. Stow the support strut on the door. Close the left door.
pin from the door, extend the telescopic strut and secure to the aircraft using Secure the forward latch. Ensure that the latch release lever is flush with the
the pippin. latch.
Push the door open until the strut locks in the fully extended position. This Secure the rear latch. Secure the three latches holding the left and right
completes the opening of the left hand door. doors together.
W ith the left hand door open. The two latches securing the right hand door
are now visible. The forward latch is released. Followed by the rear latch and To secure these latches, release the latch hook by pressing the latch release
the door is ready to be opened. lever
Use the assist handle mounted on the air inlet duct and swing the door fully
open. The door hold open mechanism incorporates a counterbalance spring  Engage the latch hook in the locking bracket
that takes most of the door weight.  Close the latch lever
The door will lock automatically in the door open position. No locking pins are  Ensure that the latch release lever is flush with the latch
necessary to secure the right hand door in the open position. A red colored
pip-pin is provided to lock the door hold open spring mechanism should it Repeat the closing procedure for the remaining latches. Carry out a final
become necessary to remove the door from the aircraft. visual inspection to ensure that all latches arc secure. This completes the
In this event the red pip-pin should be removed from its stowage and inserted APU access door closing procedure. Finally, reset the APU circuit breakers in
in the adjacent hole with a red surround. the cockpit.
To prevent injury, a placard advises against removal of the red coloured bolt
when the access door is removed.
This completes the APU door opening procedure.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 22

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU COMPARTMENT ACCESS DOORS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 23

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU DRAIN SYSTEM PRESENTATION

Fuel/Oil Pump Drain Exhaust Coupling Drain

The fuel and oil pump seal drain line is routed via a collector line to the drain The exhaust coupling drain line is routed to the drain mast. This drain line
tank. This line drains fuel or oil leaks. collects fuel, water or air leaks.

Drain-Port Air Check-Valve Drain Tank

An air check valve, mounted on the Fuel Control Unit (FCU) drain line, For venting and evacuation the drain tank is connected to the drain mast.
prevents air ingestion in the FCU.
Airflow across the drain mast creates a vacuum in the drain line. The suction
Gearbox Vent effect produced at 200 kt, is sufficient to remove the contents of the drain
tank. A vent line ventilates the drain tank and drain lines. The APU drain lines
The accessory gearbox is vented to the APU exhaust through a vent line. are connected to the right access door drain lines through spring adapter
This line vents air or oil leaks to the APU exhaust. seals (kiss seals).

Iniet Guide Vane Actuator Drain The drain mast drains any fluid leakage from the APU through four holes.

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

Flow Divider Drain

The fuel flow divider and drain valve drain line is routed via a collector line to
the drain tank. This drain line collects fuel leaks.

Turbine Plenum Drain

The turbine plenum drain line is routed alone to the drain mast. This drain
line collects fuel or air leaks.

Heat Shield Drain

The heat shield drain line is routed to the drain mast. This drain line collects
fuel, water or air leaks.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 24

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU DRAIN SYSTEM PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 25

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

AIR INT AKE SYSTEM

General

The air intake system provides ambient air of sufficient quantity and quality to up to approximately 150mm (6in) forward of the interface to the APU
the APU. The main function of the air intake system is: compartment is covered with a CRES face sheet to serve as an extension of
the APU compartment fireproof area. A fireproof gasket is used to join the air
 provide sufficient mass flow to the APU plenum chamber, inlet assembly to the APU compartment firewall.
 minimization of pressure loss and flow distortion (thus also reducing
the danger of APU surge), The air inlet consists of the following major components:
 noise reduction,
 reduce the potential for foreign object ingestion,  Air Inlet Body: This is essentially a U-shaped component, forming
 prevent exhaust (from APU and main engines) from re-entering the both side walls as well as the rear portion of the upper wall. It is of a
inlet, fiberglass fabric/ aluminum core sandwich design. The upper wall is
 prevent the ingestion of fluids existing externally, acoustically treated with feltmetal. Rails, which extend into the
 prevent the accumulation of flammable fluids in the intake system. airstream, are incorporated along the side walls in order to prevent
the ingression of fluids flowing along the tailcone outer surface.
System Description  Air Inlet Flap: It is of a fiberglass fabric/Nomex core sandwich design
without acoustic treatment. The flap is hinged at the forward end of
Fixed Diverter the air inlet body and is operated by an attached actuator. It serves
two purposes: to close the air inlet when the APU is not in operation.
This item, being installed just forward of the tailcone at the bottom the rear To form the forward portion of the upper wall when the APU is in
fuselage, serves two purposes: operation.
 Air Inlet Nose: This item forms the lower wall of the air intake and is
Its primary purpose is to improve the ram air recovery during in-flight APU permanently installed in the air inlet body. It is of a CRES
operation. This is accomplished by positioning the inlet some 50mm into the skin/aluminum core sandwich construction and is acoustically treated
airstream, thus the lowest energy portion of the aerodynamic boundary layer with feltmetal along the inlet airstream aft of the lip area.
is prevented from entering the air inlet.  Air Inlet Housing: This conventional aluminum structure attached to
the air inlet body serves two functions: provide an attachment for the
Its secondary purpose is to divert any fluids (such as oil, hydraulic or de-icing inlet flap actuator; serve as maintenance platform for work within the
fluid, fuel or water), which might be migrating aft along the fuselage during tailcone forward of the APU compartment.
flight. They are thus prevented from entering the air inlet.  Air Inlet actuator: This electrically operated linear actuator operates
the air inlet flap. Its major components are:
Air Inlet  28V DC motor with brake control (basic version),
 a limit switch at each end position,
The air inlet assembly is installed as a unit in a cutout in the bottom of the  a flap position switch at each end position,
tailcone just forward of the APU compartment. The interface to the air duct is  thermal overload protection device.
attached to the APU compartment forward firewall. The inlet airstream area

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 26

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 27

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Air Duct

The air duct forms the central portion of the air intake system, connecting the
air inlet with the APU plenum chamber. It is located completely within the
APU compartment and is installed on the access door 316AR. W hen subject
door is opened, the air duct is dislocated from its normal installation position,
thus permitting improved access to the APU. The purpose is to duct the
airflow to the APU and to reduce aerodynamic noise. In case of APU
compartment fire, it retains its shape. It consists of 2 major components:

 Diffuser: Decelerates the air stream to reduce airflow turbulence by

means of expansion
 Elbow: Redirects the air stream to the APU plenum

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 28

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

AIR INTAKE SYSTEM LAYOUT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 29

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Operation Control and Indication Closing of the Air Intake

The following components control the opening/closing of the air intake flap:  Normal APU Shutdown Procedure
W hen you release the APU MASTER SW pushbutton switch in the off
 the MASTER SW pushbutton switch, position:
 the APU main relay 4KD (APU MAIN) and  if the bleed air mode was used, a 120s cool-down cycle starts,
 the ECB.  if no bleed air mode was used, no cool-down cycle is started,
 when the APU speed has decreased to below 7%, the ECB
Opening of the Air Intake sends a 'FLAP CLOSE'-command to the air intake flap
actuator,
The following settings are required:  the air intake flap actuator moves the flap into the 'CLOSED'-
position within approximately 20s,
 busbar 301PP energized (carries 28V DC electrical power),  when the air intake flap actuator reaches the end position
 circuit breaker 1KD (ECB SPLY) closed, 'extended' (flap in 'CLOSED'-position), a 'FLAP CLOSED'-
 circuit breaker 2KD (APU CTL) closed and signal is transmitted back to the ECB,
 MASTER SW 14KD in'ON'-position.  the APU main relay 4KD is de-energized,
 electrical power is disconnected from the ECB.
W hen you push the APU MASTER SW pushbutton switch in the ON position:
 APU Emergency Stop (Ground Signal)
 the blue ON legend in the MASTER SW comes on, In case the ECB receives an 'APU EMERGENCY STOP'-command
 the APU main relay 4KD is energized, for a minimum of 50 ms, the following sequence occurs:
 electrical power is supplied to the ECB,  the ECB 59KD shuts down the APU immediately (no cool-
 the ECB transmits a 'FLAP OPEN'-command to the air intake flap down cycle),
actuator,  when the APU speed has decreased to below 7%, the ECB
 the air intake flap actuator moves the flap into the 'OPEN'-position transmits a 'FLAP CLOSE'-command to the air intake flap
within approximately 20s, actuator,
 when the air intake flap actuator reaches the end position 'retracted'  the air intake flap actuator moves the flap into the 'CLOSE'-
(flap in 'OPEN'-position), a 'FLAP OPEN'-signal is transmitted back to position within approximately 20s.
the ECB,  W hen the air intake flap actuator reaches its end position
 on the lower ECAM display unit, the FLAP OPEN indication comes 'extended' (flap in 'CLOSED'-position), a 'FLAP CLOSED'-
on. signal is transmitted back to the ECB.

After the MASTER SW has been set to the 'off-position, the following
sequence occurs:

 the APU main relay 4KD is de-energized,

 electrical power is disconnected from the ECB.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 30

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

AIR INTAKE SCHEMATIC

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 31

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU BASIC DESCRIPTION

General Turbine

The APU has a modular design. The three APU modules are: The turbine assembly drives the compressor, the load compressor and the
gear train of the accessory gearbox. The single stage radial inflow turbine
 the power section includes.
 the load compressor
 the accessory drive gearbox.  a cooled nozzle guide vane
 a rotor
Power Section  a diffuser exhaust pipe including a diffuser nozzle and seven radial
vanes.
Compressor
Load Compressor
The compressor is of a single stage centrifugal compressor design.
The load compressor is of a single stage centrifugal design.
The main components of the compressor are:
The main components of the load compressor are:
 the inlet plenum
 the impeller and the diffuser  the inlet guide vane assembly,
 the deswirl vane assembly, the compressor hub containment.  the load compressor impeller, the load compressor diffuser, the load
compressor scroll.
Combustion Chamber
Inlet Guide Vanes
The combustion chamber is of a reverse flow annular design and is installed
inside the turbine plenum. The main parts of the combustion chamber are: The Inlet Guide Vane assembly controls the amount of low pressure bleed
from the APU load compressor. The 14 Inlet Guide Vanes are moved
 the inner combustion chamber shell simultaneously by a gear train operated by an actuator.
 the outer combustion chamber shell.

The following components are installed on the combustion chamber:

 the igniter plug

 the six fuel nozzles

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 32

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU BASIC DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 33

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU IGNITION AND ST ARTING - DESCRIPTION AND OPERATION

Starter Control

The starting system rotates and accelerates the APU rotor through a clutch
and gearbox.

W hen the APU speed is about 50%, the start logic of the Electronic Control
Box cuts off the supply to the Start Contactor which switches off the Starter
Motor. The timed acceleration loop of the Electronic Control Box causes the
APU to accelerate to governed speed.

Ignition Control

The ignition system provides initial light-on of the fuel air mixture in the
combustion chamber.

The ignition system includes:

 An Ignition Exciter Unit which produces high voltage electrical energy.

 An ignition lead wich delivers electrical energy to an igniter plug
screwed into the combustion chamber.

During starting, the ECB switches on the ignition between 7% and 95%.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 34

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU IGNITION AND STARTING DESCRIPTION AND OPERATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 35

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Ignition Unit

IDENTIFICATION FIN: P10

LOCATION ZONE: 315/316

Component Description

Disconnect the low tension electrical supply 5 mins before starting work on
the ignition system. Also, ground the igniter lead with an insulated device as
you disconnect it from the igniter plug.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 36

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

IGNITION UNIT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 37

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Igniter Plug

IDENTIFICATION FIN:
LOCATION ZONE: 315/316

Component Description

Disconnect the low tension electrical supply 5 mins before starting work on
the ignition system. Also, ground the igniter lead with an insulated device as
you disconnect it from the igniter plug.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 38

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

IGNITER PLUG/IGNITION UNIT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 39

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Starter Motor

IDENTIFICATION FIN: 4005 KM1

LOCATION ZONE: 315/316

Component Description

For boroscope inspection, the APU can be rotated manually through the
starter. The starter is equipped with a brush wear indicator.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 40

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

STARTER MOTOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 41

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Accessory Gearbox

Gearbox Assembly

The gearbox transmits the shaft power to the APU accessories and to the
APU generator which are installed on the gearbox pads.

The gearbox is also the oil reservoir for the APU lubrication system.

Accessories

The components mounted on the accessory gearbox are:

 the Starter Motor Assembly

 the Cooling Air Fan Assembly
 the Oil Pump Assembly (lubrication unit)
 the Fuel Control Unit
 the AC generator.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 42

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU FUEL FEED SYSTEM DESCRIPTION

Fuel Pump

The APU fuel pump is a centrifugal pump driven by a single phase AC motor. The FUEL LO PR message is displayed on the ECAM APU page if it is
This pump is controlled to run if the APU MASTER SW pushbutton is set to selected and:
ON and the fuel crossfeed line pressure is not sufficient.  the APU speed is greater than 7% RPM
The fuel crossfeed line pressure sensor controls the operation of the APU  the fuel pressure is lower than 15.8 PSI (1.01 Bar).
fuel pump.
The APU fuel pump runs as soon as the pump inlet pressure is lower than The ECB memorizes this information in its BITE memory even if the pressure
21.8 PSI (1.50 Bar). increases above 17.3 PSI (1.19 Bar).

It stops when the pressure is above 23.2 PSI (1.60 Bar). Fuel Drain / Vent System

Fuel LP Isolation Valve A vent APU fuel line pushbutton, located on the firewall allows the APU fuel
feed line to be purged during ground maintenance.
The APU Fuel LP isolation valve is driven by two DC motors. As long as the pushbutton is held pressed in, the APU fuel LP isolation valve
This valve is open as long as the MASTER SW pushbutton is set to ON. is open and the APU fuel pump runs.
W hen closed, it prevents pressurization of APU fuel feed line and flow of fuel A fuel drain and vent valve is installed in the APU compartment at the fuel
into a specific fire zone. inlet connection to the Fuel Control Unit. It permits fuel to be drained and air
to be bled.
The APU Fuel LP isolation valve is automatically closed when:

 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 the cockpit),
 the APU SHUT OFF P/B has been pressed on the external power
receptacle panel.

APU Inlet Low Pressure Sensor

At the inlet connection of the Fuel Control Unit, a pressure sensor transmits
low pressure information through the ECB to the ECAM APU page.

APU FUEL FEED SYSTEM DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 43

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU FUEL SYSTEM DESCRIPTION

General Flow Divider and Drain Valve Assembly

The APU fuel system operates fully automatically. The purpose of the flow divider is to direct fuel to the primary and secondary
manifolds. Both manifolds supply duplex fuel nozzles.
The APU fuel system includes:
From 7% RPM, the primary nozzles are supplied with fuel above 7.5 psi.
 a fuel control unit which schedules the fuel flow, Secondary nozzles are supplied above 150 psi during acceleration and
 a flow divider and drain valve assembly which directs the fuel to running phases.
nozzles.
Time Acceleration Rate Schedule
Fuel Control Unit
The time acceleration rate schedule controls the fuel in order to cause the
The fuel flow into the fuel control unit passes through the inlet fuel filter to the APU speed to increase at a constant rate without overtemperature. It controls
high pressure fuel pump, then it goes through the high pressure filter to: the fuel torque motor of the fuel control unit.

 the Inlet Guide Vane Actuator to position the Inlet Guide Vanes. The ECB protective circuits are set to shut down the APU if a start is initiated
 the Torque Motor metering valve for flow control. and:
 the differential pressure regulator.
 Speed is less than 7% for more than 30 seconds.
The metered fuel goes through the pressurizing valve to the fuel shut-off  Speed is less than 20% for more than 50 seconds.
solenoid valve.  Speed is less than 50% for more than 70 seconds.
 Acceleration rate is below 0.2% per second with EGT above 204°C.
The fuel solenoid valve is normally closed. It is electrically controlled to open  EGT is below 204°C with speed more than 7% for 15 seconds.
by the ECB when the speed is above 7% RPM. W hen the fuel solenoid valve
is open, the pressurizing valve ensures that the appropriate working fuel
pressures are available to the system.

The high pressure fuel pump will produce more fuel flow than will be required
to support combustion under any given RPM. A differential pressure
regulating valve bypasses the excess fuel back to the filter inlet.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 44

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU FUEL SYSTEM DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 45

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Speed Control

The ECB controls the speed by means of the fuel torque motor according to
air conditioning zone controller and Main Engine Start demands.

On Ground

The ECB maintains the speed at:

 99% RPM if there is no bleed air demand

 99% RPM for air conditioning below 25°C
 101 % RPM for air conditioning above 30°C
 101% RPM for Main Engine Start

In Flight

The ECB maintains speed at:

 101% RPM

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 46

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

FUEL SYSTEM COMPONENTS

Fuel Control Unit

IDENTIFICATION FIN: 4005 KM2

LOCATION ZONE: 315
MMEL NOT LISTED

FUEL CONTROL UNIT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 47

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 48

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

COMPONENTS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 49

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU AIR SYSTEM DESCRIPTION

Inlet Guide Vanes Exhaust Gas Temperature (EGT)

Depending on the load demand, the ECB controls the speed of the APU and The bleed air flow is reduced as a function of compressor inlet temperature
the Inlet Guide Vanes to modulate the air flow available from the load and Exhaust Gas Temperature. The EGT cannot exceed a limit set in the
compressor. The Inlet Guide Vanes (IGVs) are driven by an actuator ECB.
operated by fuel pressure, and controlled by a torque motor signalled from
the ECB. T2 is the Load Compressor Inlet Temperature (LCIT). T5 is the EGT. The
EGT limit is set in the ECB and memorized by the EPROM.
During the start sequence, the IGVs are fully closed below 50% RPM, 10°
open between 50% and 75% RPM and 22° open above 75% RPM. Note: The APU bleed air system is used for Main Engine Starting (MES) and
The minimum open or idle position of the IGVs when the APU is running is Air Conditioning (ECS).
22°.
The maximum open position of the IGVs is 88°. Above 23000ft, the IGVs Generator Load
assume the idle position and below 21000ft they will open on demand.
If the APU generator load increases, the ECB reduces the bleed air load by
Environmental Control System (ECS) Load controlling the Inlet Guide Vanes to close.

In response to the Environmental Control System (ECS) signal coming from If a generator shock load occurs (speed decreasing by more than 10% RPM
the air conditioning zone controller, the Inlet Guide Vane position may not per second) the IGVs are closed for 3 seconds.
exceed limits set in the ECB.

APU speed is 99% RPM if ambient temperature is below 30°C (+86°F) or

101% RPM if above.

The Inlet Guide Vanes modulate within limits. The ECS limits are: ECS MIN,
ECS COLD, ECS NORMAL, ECS HOT, memorized by the Erasable
Programmable Read Only Memory (EPROM) which is part of the ECB.

Main Engine Start (MES) Load

In response to the Main Engine Start (MES) signal coming from the Engine
Interface Unit, the ECB sets the Inlet Guide Vanes to the fully open position.
The Inlet Guide Vanes are fully opened. The APU speed is controlled to
101%.
The MES load is limited by an MES limit set in the ECB and memorized by
The EPROM.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 50

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU AIR SYSTEM DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 51

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

AIR SYSTEM COMPONENTS

Load Bleed Valve Surge Control Valve

IDENTIFICATION FIN: 110 KD IDENTIFICATION FIN: 111 KD

LOCATION ZONE: 316 LOCATION ZONE: 316
MMEL NOT LISTED MMEL NOT LISTED

Component Description Component Description

The load bleed valve is located on the T-duct to the right of the APU. The surge control valve is located on the T-duct to the right of the APU.
It is a two-position valve, open/close, controlled by a solenoid. It is a modulating valve controlled by a torque motor. The purpose of the
The valve is selected from the APU BLEED pushbutton switch, and surge control valve is to prevent load compressor surge on changing
controlled by the ECB. operating conditions.
The filter may be cleaned by washing in warm soapy water, rinsing in clean
water and drying with compressed air (max. 1.0 bar /14.5 PSI).

AIR SYSTEM COMPONENTS - LOAD BLEED VALVE SURGE CONTROL VALVE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 52

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Air Sensing Elements P2 Sensor

IDENTIFICATION FIN: 117 KD IDENTIFICATION FIN:

LOCATION ZONE: 316 LOCATION ZONE: 316
MMEL NOT LISTED MMEL NOT LISTED

Component Description Component Description

The air sensing elements are located on the T-duct between the surge valve The P2 sensor is located on the right side of the compressor inlet plenum.
and the bleed valve.
It provides an input signal which is used by the ECB to modify the schedules
Electrical signals from the differential pressure transducer and the total of the surge valve and the APU fuel control.
pressure transducer are used by the ECB to control the surge valve.
It is a class 3 failure.
The air sensing elements are class 1 failures.

AIR SENSING ELEMENTS

P2 SENSOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 53

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Load Compressor Discharge Temperature Sensor (LCDT) Load Compressor Inlet Temperature Sensor (LCIT)

IDENTIFICATION FIN: 102 KD

LOCATION ZONE; 316 IDENTIFICATION FIN: 101 KD
MMEL NOT LISTED LOCATION ZONE: 316
MMEL NOT LISTED
Component Description
Component Description
The LCDT is located in the discharge duct leading to the load bleed valve.
The LCDT provides an input signal to the ECB for indication. It is a class 3 The LCIT sensor is located below the IGV actuator. The sensor provides an
failure. input signal which is used by the ECB in the reverse flow protection logic.
The LCIT sensor is a class 3 failure.

LOAD COMPRESSOR DISCHARGE TEMPERATURE SENSOR (LCDT) LOAD COMPRESSOR INLET TEMPERATURE SENSOR (LCIT)

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 54

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

COMPONENTS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 55

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

IGV Actuator

IDENTIFICATION FIN:
LOCATION ZONE: 313
MMEL NOT LISTED

Component Description

IGV actuator adjustment:

 Ensure IGV clevis is screwed fully into the IGV rod.

 Ensure IGVs are fully closed.
 Engage IGV clevis with actuator linkage screw.
 If necessary, adjust actuator linkage screw to close the IGVs. The
IGV position is determined by a position fixture entered in the LCIT
mounting.

IGV ACTUATOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 56

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 57

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Control and Monitoring APU SYSTEM MANAGEMENT

APU control and monitoring are performed by the Electronic Control Box
(ECB). Running Sequence - Air Intake Flap Sequence
Should a fault occur during APU operation, the ECB records it and sends the
fault message to the ECAM system and to the centralized maintenance W hen the APU MASTER SW is set to ON, the ECB is electrically supplied
system. The ECB also acts as interface between the aircraft and the APU. and initiates a power up test. The APU fuel system is energized and the air
The ECB has a built in test equipment used for the power up test and the intake flap is controlled to open.
monitoring test. The APU fuel LP isolation valve opens and the APU fuel pump logic is
The ECB receives the APU Data and sends main parameters to the ECAM energized (the APU fuel pump will run as long as the main engine fuel feed
system. line pressure is lower than 23 psi (1.56 bar)).
The parameters and the indications displayed on the APU ECAM page are: The ECB controls the opening of the air intake flap. W hen it is fully open (in
20 seconds) the ECB receives a flap open signal.
 Speed (N) and Exhaust Gaz Temperature (EGT).
 Bleed pressure and APU Generator. Running Sequence - Start Sequence
 Inlet flap position.
 Low Oil level and low fuel pressure. Then, when the START pushbutton has been pressed, the ECB initiates the
Start Sequence by closing the start contactor only if the listed conditions are
AC Generator met. Start contactor is closed if:

An oil cooled APU Generator (90 KVA) can supply the aircraft electrical  the POW ER UP test is completed
network.  10 seconds delay after setting the MASTER SW pushbutton to ON (in
The APU, driven by the accessory gear box, uses the APU shaft power. flight only)
If the APU load increases, the Inlet Guide Vanes close in order to give priority  the APU speed is less than 7% RPM
to electrical power supply over the pneumatic supply.  no shutdown initiated.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 58

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

RUNNING SEQUENCE AIR INTAKE FLAP SEQUENCE - START SEQUENCE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 59

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Running Sequence - Acceleration Sequence

The APU spool speed is monitored by two identical speed sensors installed The surge control valve torque motor is controlled by the ECB according to
on the gearbox casing. The ECB takes into account the highest speed signal the total pressure and the differential pressure measured by pressure
for APU contrcl and ECAM display. sensors at the discharge of the load compressor.
N represents the percentage of APU RPM. The load compressor pressure is a function of the inlet guide vane position.
At 7%, the ECB energizes the igniter and opens the fuel solenoid valve on W hen the APU bleed load control valve is open, the air conditioning zone
the Fuel Control Unit. The ECB also sets the correct metered quantity of fuel controller sends a demand signal to the Electronic Control Box in order to
for engine light-up. control the Inlet Guide Vane position and APU speed accordingly. The Inlet
The metered quantity of fuel is adjusted by the Fuel Torque Motor. Guide Vane (IGV) position determines the air flow delivered to the pneumatic
The light-up phase is confirmed by the increase in EGT. system.
This temperature is monitored by two sensors which send a signal to the The speed of the APU is 99% RPM in ambient temperatures lower than 30°C
ECB. (86°F) and 101% RPM in temperatures higher than 30°C. For Main Engine
The ECB takes into account the highest temperature value for APU control Start, APU speed is 101% RPM.
and ECAM display (EGT). The EGT increases as the APU accelerates, with W hen the APU bleed valve is closed the Inlet Guide Vanes move to the idle
starter motor assistance to 50% RPM where the ECB cuts off the starter position.
contactor electrical supply. The surge control valve allows the discharge of air from the load compressor.
At 50% RPM, the Inlet Guide Vanes move to 10° open to avoid compressor
surge.
Above 50% RPM, the APU continues to accelerate under its own power to
governed speed.
To prevent APU load compressor surge a leakage flow is sent to the APU
exhaust through the control valve. The surge control valve is pneumatically
operated and electrically controlled by a torque motor.
The APU continues to accelerate under the control of the ECB.
At 75% RPM, the Inlet Guide Vanes move to 22° open.
As the APU accelerates, the ECB transmits a signal to the torque motor of
the Fuel Control Unit.
This controls the metered fuel flow to the governed speed.
The ECB has a protection called Time Acceleration Loop. It controls the fuel
flow so that the APU speed increases at a constant rate from 0 to 95% within
operating temperature limits.
W hen the APU speed reaches 95%, the igniter is de-energized, the
combustion is self sustaining. 2 seconds after 95% RPM has been reached
the AVAIL light comes on and the ON light goes off on the START
pushbutton. This indicates that the APU is available to supply pneumatic and
electrical power.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 60

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

RUNNING SEQUENCE - ACCELERATION SEQUENCE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 61

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Running Sequence - Pneumatic and Electrical Supply

The ECB monitors the oil temperature, pressure and level.

Normal Shutdown Sequence - Pneumatic and Electrical Supply

An APU normal shutdown is initiated when the MASTER SW pushbutton is

released out.
If the APU bleed air is selected, the ECB sends a signal to close the APU
bleed load valve and initiate a cool down cycle so that the APU shutdown is
delayed. If the APU bleed air is not selected, the APU shuts down
immediately.
The normal shutdown signal closes the fuel solenoid valve of the Fuel
Control Unit. This causes the APU to shut down.

Note: The AVAIL indications goes off and the AC generator de-energized.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 62

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

RUNNING SEQUENCE - PNEUMATIC AND ELECTRICAL SUPPLY NORMAL SHUTDOWN SEQUENCE - PNEUMATIC AND ELECTRICAL SUPPLY

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 63

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Normal Shutdown Sequence - Deceleration Sequence

The APU decelerates.

W hen the speed is less than 50%, the Inlet Guide Vanes go progressively to
the closed position.
W hen the speed is less than 7% RPM, the air intake flap is controlled to fully
close.
The surge control valve is electrically signalled to progressively open during
APU roll down and remains spring loaded open.

Normal Shutdown Sequence - Air Intake Flap Sequence

W hen the air intake flap is fully closed and the APU has stopped, the ECB is
no longer electrically supplied.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 64

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

NORMAL SHUTDOWN SEQUENCE DECELERATION SEQUENCE -AIR INTAKE FLAP SEQUENCE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 65

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Protective Shutdown

W hen the ECB is electrically supplied, it controls the APU starting and
running phases. If an abnormal parameter is detected, it initiates an
immediate shutdown without time delay, even if APU bleed air system is
used.

ECB PROTECTIVE SHUTDOW N 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 POW ER
 ECB FAILURE
 GENERATOR HIGH OIL TEMPERATURE
 LOSS OF SPEED SENSING
 IGV SHUTDOW N

Emergency Shutdown

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

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 66

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

PROTECTIVE SHUTDOWN - EMERGENCY SHUTDOWN

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 67

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

INDICAT ION AND MONITORING SYSTEM

Speed Sensors ( 2 )

It is necessary for the APU control system to have a correct speed signal.
Two identical, but separate speed sensors are used. They are located on the
gearbox casing. A phonic wheel with 24 teeth is attached to the rotor shaft.
The gap between the phonic wheel and the speed sensor is 5 mm and is
non−adjustable.

Electronic Components in the ECB

The two sensors are connected to the ECB which calculates the average
value of the sensors’ signals. W hen the signal difference is greater than 5%,
the sensor with the highest value is selected. This voltage ( signal ) is sent to
an ARINC driver which, through the ARINC 429 bus, supplies the speed
information to the system page of the ECAM.

Indication

The system page of the ECAM shows the APU speed information. The ECB
59KD transmits the speed information to the ECAM through the ARINC 429
Bus as a binary word with Label 176. The display format has :

 an analog scale from 0 % to 120 % with an amber box at 102 % and

with a RED sector for speeds more than 105 %,
 a digital readout in %

Note: A speed signal is also delivered by the PMG ( part of the cooling fan ).
This speed signal is used by the back−up overspeed protection 107 %.

RPM SPEED SENSOR DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 68

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

SPEED SENSOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 69

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Serial Number Encoder

IDENTIFICATION FIN: 116 KD

LOCATION ZONE: 315

Component Description

The Electronic Control Box (ECB) resets automatically the cycles and hours
to zero when it sees a change in APU serial number.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 70

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

SERIAL NUMBER ENCODER

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 71

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

EGT Sensor

IDENTIFICATION FIN: 114 KD, 115 KD

LOCATION ZONE: 315/316

Component Description

The two EGT rakes (EGT sensors) are independent and the ECB uses the
higher value. In case of one rake failure, the ECB uses the remaining one.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 72

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

EGT SENSOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 73

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

ENGINE CONTROL

Electronic Control Box

Function Main Components

The Electronic Control Box (ECB) controls and monitors the Auxiliary Power The main components are:
System.
 The ECB enclosure which houses Printed W iring Assemblies (PW A)
Location  The ECB front face which includes:
 A RS 232-C connector
The ECB is installed in the cargo compartment (rear lower part of the  A front cover door housing the On Board Replaceable Memory
fuselage). Module (OBRM)
 A handle
Main features  The ECB rear face which includes an ARINC 600 connector.
 Full Authority Digital Electronic Controller (FADEC) Identification
 Hybrid design for size and weight reduction
 Erasable Programmable Logic Device (EPLDs) for design flexibility The electronic control box has an identification plate and a modification plate,
and reduced component count both located on the front face of the ECB close to the front cover door.
 Modular design for reliability, main tenability and testability
 No calibration required
 Digital communication links (ARINC429 and RS232-C).

Dimensions

 W idth: 159 mm (6.2 inches)

 Height: 195.4 mm (7.6 inches)
 Depth: 375.4 mm (14.6 inches).

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 74

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

ECB

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 75

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

ECB INTERFACES

Power Supply

The Electronic Control Box is electrically supplied, through the APU main  The Automatic Fire Extinguishing System.
control relay, by at least one of the aircraft batteries, the aircraft DC network  The APU FIRE handle pushbutton in the cockpit and the APU SHUT
and/or from the 115 V AC APU generator (during a power failure up to 230 OFF switch on the External Power Control Panel.
ms).
During flight:
Master Switch Pushbutton
 The APU FIRE handle pushbutton in the cockpit.
The APU MASTER SW ITCH provides the ECB with a supply and reset signal
and with a shutdown signal. LGCIU 1
The Electronic Control Box sends a signal to the FAULT light when an
automatic shutdown occurs or a Power Up Test fails. The ECB receives the flight/ground discrete input signal from the Landing
Gear Control and Interface Unit 1.
Start Pushbutton This signal is used for automatic shutdown inhibition logic and for failed
sensor logic.
This discrete input signal from the A/C initiates the timed acceleration loop
which controls the APU acceleration from 0 to 95% speed. ElUs
In flight the START switch has a time delay of 10 sees. The ECB illuminates
the ON light during APU start sequence. During engine start, the Engine Control Box receives the Main Engine Start
A discrete output signal to the aircraft energizes the AVAIL light in the signal from Engine Interface Unit 1 or 2.
START pushbutton when the APU speed is above 95%. This discrete input signal causes the ECB to position the Inlet Guide Vanes
to a preselected angle.
Back Up and Main Start Contactors

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

Emergency Stop

A discrete input signal from the A/C initiates the APU shutdown logic 100
msecs after the ECB has received this signal.
The sources for emergency stop signals are:
On ground:

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 76

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

ECB INTERFACES

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 77

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

BMCs

W hen the APU bleed pushbutton is set to ON, BMC 1 or 2 sends a discrete
input to the ECB which may control the APU bleed valve to open.

TSO/JAR

The ECB receives a discrete input from the aircraft signature PIN
programming This open or ground signal determines whether the ECB
follows the Technical Standard Order or the Joint Airworthiness
Requirements.

Environment Control System

The ECB receives, via an ARINC 429 bus, an input from the Zone Controller
to increase the APU speed. The ECB sends a discrete output to the Zone
Controller to signal that the APU bleed valve is open.

A320/321

The ECB receives a discrete input from the aircraft signature PIN
programming This identification PIN allows the ECB to identify A321
applications for functional differences from those of an A320.

SDACs

The ECB sends to SDACs 1 and 2, via ARINC 429 Data buses, the
indications to be displayed on the ECAM APU page and shutdown
information to trigger the corresponding warnings.

CFDS

The ECB is a type 1 computer.

The ECB is connected to the Centralized Fault Display System through Data
buses (ARINC 429).

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 78

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 79

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU ECAM PAGE PRESENTATION

General

The APU indications are displayed on the lower ECAM page.

This page is called manually or automatically during APU start.

Exhaust Gas Temperature

The Exhaust Gas Temperature is displayed green in normal configuration.

This includes the pointer symbol and digital indication.
It pulses in advisory mode.
It becomes amber or red in case of over-temperature.
A movable red line is computed by the ECB.The red EGT limit value is
different during APU starting and when APU 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 the air intake flap is fully
open.
No indication is displayed otherwise.

 FLAP OPEN Displayed steady: Air intake flap fully open with the
MASTER SW push-button set to ON.
 FLAP OPEN Displayed pulsing: Air intake flap not fully closed 3
minutes after the MASTER SW push-button has been set to OFF.

Avail

W hen the APU is running, a green APU AVAILable indication appears on the
upper ECAM page.
The green AVAILable indication is displayed when the APU speed is above
95%. Nothing is displayed otherwise.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 80

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU ECAM PAGE PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 81

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU Generator

The APU electrical generator output is displayed as shown on the picture.

The load voltage or frequency indication is displayed amber when the

corresponding parameter is out of range. The APU generator parameters are
displayed amber in case of overload, or voltage or frequency are out of
range.

APU ECAM PAGE PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 82

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU Bleed Low Oil Level

The APU bleed valve indication is displayed as shown on the picture. The green LOW OIL LEVEL indication pulses when the oil in the gearbox
The APU bleed pressure indication is replaced by amber crosses when the reaches the low level an needs servicing.
indication is not available.
 If the oil quantity decreases below 3.9 qt(3.69 I), the indication pulses
Fuel Low Press on the APU ECAM page.

The Amber Fuel Low Pressure indication is displayed when the pressure
upstream the fuel control unit is too low.

 The amber FUEL LO PR message is displayed when the fuel

pressure, in the APU fuel feed line, is below 15 PSI.

APU ECAM PAGE PRESENTATION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 83

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU WARNINGS

Auto Shut Down

If an AUTO SHUT DOW N 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 ECAM page is called automatically.

AUTO SHUT DOW N when:

 Overspeed
 Overtemperature
 Low oil pressure
 High oil temperature
 Start period timer
 Sensor failure EGT or LOP switch
 Air intake flap closed
 IGV shut-down
 No flame
 Reverse flow
 No acceleration
 DC power lost
 ECB failure
 Generator high oil temperature
 Loss of speed sensing

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 84

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

AUTO SHUT DOWN

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 85

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Emer Shut Down

If an EMER SHUT DOW N 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 ECAM page is called automatically.

An EMER SHUT DOW N occurs when:

 The APU shut off pushbutton is pressed on the external power control
panel.
 The APU FIRE pushbutton is released out on the overhead panel.
 The automatic fire extinguishing logic is triggered on ground.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 86

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

EMER SHUT DOWN

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 87

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

CFDS SPECIFIC PAGE PRESENTATION

APU Data/Oil Shutdowns

To gain access to the SYSTEM REPORT/TEST APU MENU, the APU The APU SHUTDOW NS page gives the reason of the shutdown
MASTER SW ITCH must be set to ON. (OVERSPEED) and the related LRUs causing the fault (classed in
descending probability order). Refer to the TSM to trouble shoot the faulty
The APU is a type 1 system. It is not available in CFDS back-up mode. component which caused the shutdown.

The APU DATA/OIL page gives the:

 APU serial number

 APU operating hours
 APU cycles
 APU oil level.

"OIL LEVELLOW " replaces "OIL LEVELOK" when the oil quantity decreases
to 3.69 I (3.9 qt.).

Each APU contains a serial number encoder which provides the information
required for proper CFDS interpretation, continuity of LRU fault history, hours
and cycles of the APU.

W hen you replace an APU or a serial number encoder, the ECB resets the
APU hours and cycles to zero. The Data Management Unit (DMU) of the
Aircraft Integrated Data System (AIDS) also calculates the APU hours and
cycles so that their records are not lost when an ECB is replaced.

Performance Settings

The APU Performance Settings page gives the settings of:

 EGT trim
 COOLDOW N time

Base maintenance staff cannot modify these settings which are programmed
by adjusting the various electronic switches within the ECB (5 levels
available) following the aircraft operating conditions.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 88

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

CFDS SPECIFIC PAGES

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 89

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU OIL SYSTEM DESCRIPTION

Oil Reservoir Pressure Pump

The sump of the APU accessory gearbox is the oil reservoir. Oil is serviced The Pressure Pump driven from the accessory gearbox supplies oil to the oil
through either a pressure fill port or a gravity fill port. cooler.

The accessory gearbox sump contains 5.7 I (1.5 US gal) of oil. The oil pressure is controlled at 60 psi (4.1 bar) by a Pressure Regulating
Valve (PRV).
An APU oil heater is installed on the APU gearbox. W hen the APU Master
Switch is not set to ON, the oil heater monitors the oil temperature in the Oil Cooler
reservoir between 21 °C (70°F) and 43°C (110°F).
The pressurized oil flows through a thermal bypass valve to the oil cooler.
Level Monitoring The oil cooler uses airflow from a fan driven by the accessory gearbox.

An oil quantity switch, installed in the gearbox sump and connected tothe At low temperatures, most of the oil bypasses the oil cooler. Between 60°C
Electronic Control Box monitors the oil level for ECAM and CFDS. and 77°C (140°F and 171°F), the thermal bypass valve progressively closes,
forcing the oil to pass through the oil cooler.
On ground, when the oil quantity decreases to 3.69 I (3.9 qt) and the oil
temperature is less than 66°C (150°F), the APU page shows a pulsing green Oil Users
LOW OIL LEVEL message. A sight glass on the left side of the gearbox gives
a visual indication of the oil level. The cooled and bypassed oil is filtered and then flows to the bearings,
gearbox and generator.
Gearbox Pressurization
The filter, if clogged, is bypassed and a differential pressure indicator shows
To improve operation at high altitude, the accessory gearbox is pressurized this condition.
with air tapped from the turbine bearing housing.

The gearbox is vented through an air/oil separator, the air being discharged
into the APU exhaust and oil returned to the gearbox sump.

The gearbox pressurizing valve limits the gearbox/ambient differential

pressure to 8 PSI.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 90

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

APU OIL SYSTEM DESCRIPTION

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 91

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Scavenge Pumps

Two scavenge pumps return the oil to the accessory gearbox.

One scavenge pump driven together with the pressure pump returns the
power section rear bearing oil.
The other scavenge pump returns the generator oil through a separate filter.
Oil from the power section forward bearing, gearbox bearings, gears and
starter clutch returns by gravity.

Oil Monitoring

The ECB monitors the oil pressure and oil temperature.

The ECB will shut down the APU if:

 the Low Oil Pressure switch (LOP) senses pressure below 35 psi
(2.38 bar);
 the High Oil Temperature switch (HOT) senses temperature above
152°C (305.6°F);
 the generator oil temperature is above 185°C (365°F).

De-Oil System

The de-oil system admits air into the oil pump inlet to break the suction of the
oil pump.
This reduces oil pump resistance on APU cold start and assists in purging
the oil system on APU roll-down. The De-oil solenoid is energized on start 0-
60% RPM if:

 oil temperature is less than 20°F (-7°C).

 oil temperature is between 20°F and 40°F (-7°C and 4.4°C), and T2 is
less than -20°F (-29°C).
 P2 is less than 4.862 PSI (0.33 bar) (above 28000 ft).

The De-oil solenoid is energized on roll-down:

 from 95% RPM to 7% RPM, plus 5 seconds.

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 92

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

OIL SYSTEM COMPONENTS

Lubrication Unit

IDENTIFICATION FIN: 4005 KM6

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The steel shaft of the pump is spline driven from the gearbox and runs on
bronze bushes that are force-lubricated with oil.
On pump replacement, some components must be transferred to the new
unit.
See the Maintenance Manual for details.

OIL SYSTEM COMPONENTS - LUBRICATION UNIT

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 93

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Drain Plug

IDENTIFICATION FIN:
LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The drain plug contains a chip detector.

W hen the chip detector is removed, a check valve prevents oil loss.

DRAIN PLUG

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 94

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Oil Level Sensor

IDENTIFICATION FIN: 119KD

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The oil level sensor contains reed type switches activated by a magnet
embedded within a float.

OIL LEVEL SENSOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 95

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Generator Scavenge Pump

IDENTIFICATION FIN: 4005 KM4

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The scavenge pump forces oil from the generator through the scavenge filter
into the gearbox.

GENERATOR SCAVENGE PUMP

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 96

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

De-Oil Valve

IDENTIFICATION FIN: 117KD

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The de-oil valve permits air to enter the suction side of the lubrication pump
to reduce the starter load in the following conditions:

 if the oil temperature is below 20°F (-7°C).

 if the oil temperature is between 20°F and 40°F (-7°C and 4.4°C), and
T2 is below -20°F (-29°C).
 if P2 is below 4.862 PSI (0.33 bar) (above 28000ft).

It opens each shutdown between 95% and 7% RPM, plus 5 seconds.

DE-OIL VALVE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 97

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Cooling Fan

IDENTIFICATION FIN: 4005 KM5

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The fan bearings are oil lubricated through a transfer tube from the gearbox.

COOLING FAN

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 98

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Oil Cooler Assembly

IDENTIFICATION FIN: 4005 KM3

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The bypass valve contains a thermostat valve which is open below 60°C
(140°F) and closed above 77°C (170.6°F).
At low temperatures, oil bypasses the oil cooler. If the oil cooler should clog,
the bypass valve opens at 50 PSI (3.4 bar).

OIL COOLER ASSEMBLY

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 99

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Low Oil Pressure / High Oil Temperature Switches

IDENTIFICATION FIN: 121KD, 120KD

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The Low Oil Pressure switch contacts open to signal low oil pressure at 27.5
PSI (1.87 bar).
The High Oil Temperature switch contacts open to signal high oil temperature
at 152°C (305.60°F).

LOW OIL PRESSURE / HIGH OIL TEMPERATURE SWITCHES

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 100

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Pressure Regulator Valve

IDENTIFICATION FIN: P16

LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The pressure regulator valve controls the gearbox pressure to 8 PSI (0.54
bar) whenever the APU is running.

PRESSURE REGULATOR VALVE

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 101

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Oil Filters

IDENTIFICATION FIN:
LOCATION ZONE: 315
MMEL NOT LISTED

Components Description

The elements for the generator oil scavenge filter and the oil pump pressure
filter are identical.

The differential pressure indicator extends at 20 PSI (1.36 bar).

A bypass valve opens at 60 PSI (4.10 bar).

OIL FILTERS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 102

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Oil Ports

IDENTIFICATION FIN:
LOCATION ZONE: 315
MMEL NOT LISTED

Components Description

W hen using the pressure fill port, do not overfill the APU.

OIL PORTS

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 103

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Sump Oil Temperature Sensor

IDENTIFICATION FIN:
LOCATION ZONE: 315
MMEL NOT LISTED

Component Description

The sump oil temperature sensor signal is used by the ECB in the de-oil
system circuit.

SUMP OIL TEMPERATURE SENSOR

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 104

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

Oil Heater

IDENTIFICATION FIN: 2KT

LOCATION ZONE: 316
MMEL NOT LISTED

Component Description

The APU oil heater has an oil temperature switch which is a thermal
temperature delay switch, measuring the ambient temperature of the oil in
the reservoir. It also has an heater coil which is made of a nickel iron alloy,
using 115 V AC power to increase the oil temperature during cold soak
condition.

OIL HEATER

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 105

Airbus A318/A319/A320/A321 (CFM56) and AT A 49
Airbus A319/A320/A321 (IAE V2500) B1.1 (sub-) cat. APU – GARRETT GTCP 36-300

THIS PAGE IS INTENTIONALLY LEFT BLANK

ISSUE 1, 17 Jul 2013 FOR TRAINING PURPOSES ONLY Page: 106