W DOC AIRBUS | AMM A320F

Operational Test of the APU


TASK 49-00-00-710-008-A
Operational Test of the APU


WARNING: MAKE SURE THAT THE FWD AVIONICS ACCESS DOOR 811 IS OPEN WITH A WARNING PLACARD ATTACHED TO IT. THE WARNING NOTICE MUST TELL PERSONS NOT TO CLOSE THE DOOR. THIS PREVENTS ACCIDENTAL PRESSURIZATION OF THE AIRCRAFT.
WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).
WARNING: WHILE THE APU OPERATES, DO NOT GO INTO THESE AREAS:
  • THE AREA BEHIND THE APU EXHAUST DUCT: 25m (82ft.) REARWARD OF THE DUCT, MORE THAN 3m (10ft.) ABOVE THE GROUND, AND THE WIDTH OF THE HORIZONTAL STABILIZER
  • THE AREA AROUND THE APU AIR-INTAKE: 2m (7ft) AROUND THE INTAKE
  • THE AREA OF THE OIL-COOLER OUTLET.
THERE IS A RISK OF INJURY IF YOU GO INTO THESE AREAS.
WARNING: DO NOT START THE APU WHEN THE AIRCRAFT IS IN THE HANGAR. WHEN THE APU OPERATES, THERE ARE RISKS OF INJURY FROM HIGH TEMPERATURES AND DANGEROUS FUMES (THAT CAN FILL THE HANGAR). MAKE SURE THAT PERSONS STAY AWAY FROM THE EXHAUST DUCT. THE EXHAUST DUCT IS DANGEROUS.
CAUTION: DO NOT USE THE APU DURING FLUID DE-ICING OPERATIONS. DE-ICING FLUID CAN CONTAMINATE THE INSIDE OF THE APU.
CAUTION: DO NOT START OR TRY TO START THE APU MORE THAN THREE TIMES, ONE AFTER THE OTHER. AFTER THE THIRD TIME, THERE MUST BE A MINIMUM OF ONE HOUR BEFORE YOU START OR TRY TO START THE APU AGAIN. THIS MAKES SURE THAT THE TEMPERATURE OF THE STARTER MOTOR DECREASES SUFFICIENTLY.
CAUTION: DO NOT START THE APU WITH ACCESS DOORS 315AL AND 316AR OPEN/REMOVED. THE APU FIRE EXTINGUISHER SYSTEM IS NOT SUFFICIENT TO EXTINGUISH A FIRE IF THE ACCESS DOORS 315AL AND 316AR ARE OPEN/REMOVED.
CAUTION: OBEY THE SAFETY PRECAUTIONS.
FIN: 4005KM ** ON A/C NOT FOR ALL
1. Reason for the Job
Self explanatory
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
WARNING NOTICE(S)
 B. Work Zones and Access Panels
ZONE/ACCESS
ZONE DESCRIPTION
811
 C. Referenced Information
REFERENCE
DESIGNATION
TASK 23-44-00-860-001-A
Operation of the Service Interphone System
TASK 24-41-00-861-002-A
Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01
Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02
Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A
De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01
De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02
De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 26-22-00-710-001-A
Operational Test of the APU Fire-Extinguishing Loop/Squib
TASK 29-00-00-864-001-A
Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 31-60-00-860-001-A
EIS Start Procedure
TASK 34-10-00-860-002-A
ADIRS Start Procedure
TASK 49-00-00-710-005-A
Self-Test of the ECB
TASK 52-41-00-010-002-A
Open the Avionics Compartment Doors for Access
TASK 52-41-00-410-001-A
Close the APU Doors after Access
3. Job Set-up
Subtask 49-00-00-941-058-A ** ON A/C NOT FOR ALL
A. Safety Precautions
WARNING: WHILE THE APU OPERATES, DO NOT GO INTO THESE AREAS:
  • THE AREA BEHIND THE APU EXHAUST DUCT: 25m (82ft.) REARWARD OF THE DUCT, MORE THAN 3m (10ft.) ABOVE THE GROUND, AND THE WIDTH OF THE HORIZONTAL STABILIZER
  • THE AREA AROUND THE APU AIR-INTAKE: 2m (7ft) AROUND THE INTAKE
  • THE AREA OF THE OIL-COOLER OUTLET.
THERE IS A RISK OF INJURY IF YOU GO INTO THESE AREAS.
   (1) Make sure that the danger areas are clear of persons and/or equipment.
   (2) Close the APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
   (3) If an emergency or a malfunction occurs during operation of the APU, do the emergency shutdown procedure immediately. You can start the emergency shutdown from:
  • The APU FIRE PUSH pushbutton switch on the panel 20VU.
  • The APU SHUT OFF pushbutton switch on the panel 108VU.
NOTE: Do the emergency shutdown immediately if fire, smoke, unusual noise, fuel or oil leakage occurs.
Subtask 49-00-00-860-075-A ** ON A/C NOT FOR ALL
B. Aircraft Maintenance Configuration
   (1) Open the access door 811 (Ref. AMM TASK 52-41-00-010-002).
     (a) Put the WARNING NOTICE(S) in position on the opened access door 811 which tells persons not to close the door.
   (2) Energize the aircraft electrical circuits.
     (a) On the ELEC section on the panel 35VU:
  • Make sure that the BAT 1 and BAT 2 pushbutton switches are in the auto position (the OFF and FAULT legends are off).
     (b) Energize the aircraft electrical circuits from the external power (Ref. AMM TASK 24-41-00-861-002).
   (3) Make sure that there is sufficient fuel in the A/C fuel system.
   (4) Depressurize the aircraft hydraulic systems
(Ref. AMM TASK 29-00-00-864-001).
   (5) Make a service interphone connection from the cockpit to the APU compartment area (Ref. AMM TASK 23-44-00-860-001).
   (6) On the AIR COND section of the panel 30VU:
  • Make sure that the APU BLEED pushbutton switch is in the off position (the ON and FAULT legends are off).
  • Make sure that the X BLEED selector switch is in the AUTO position.
   (7) On panel 115VU:
  • Make sure that both ENG MASTER control switches are in OFF position.
   (8) Do the EIS start procedure (upper ECAM DU and lower ECAM DU only)
(Ref. AMM TASK 31-60-00-860-001).
     (a) On the ECAM control panel, push the APU pushbutton switch (on the lower ECAM DU, the APU page comes on).
   (9) Do the start procedure of the ADIRS (Ref. AMM TASK 34-10-00-860-002).
NOTE: If the ADIRU 2 is selected OFF or not available the APU Bleed Pressure indication is replaced by amber 'XX'.
   (10) Make sure that the APU fire and overheat detection system and the APU fire extinguishing system are operational (Ref. AMM TASK 26-22-00-710-001).
   (11) Remove the APU air intake and exhaust blanking plugs.
   (12) If not required during operation of the APU, remove the ground support equipment, the special and standard tools and all other items.
   (13) Do the ECB self test (Ref. AMM TASK 49-00-00-710-005).
   (14) Get access to the CFDS/AVIONICS STATUS page:
  • Turn the MCDU1(2) BRT knob.
  • Push the MCDU MENU mode key.
  • Push the line key adjacent to the CFDS indication.
  • Push the line key adjacent to the AVIONICS STATUS indication.
Keep the AVIONCS STATUS active during the operational test of the APU.
Subtask 49-00-00-865-077-A ** ON A/C NOT FOR ALL
C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
49VUAPU/FUEL/BLOW OFF/PUMP2QCB14
121VUAPU/FUEL/BLOW OFF/CTL1QCK39
121VUAPU/FIRE AND OVHT/DET/LOOP B2WGL44
121VUAPU/FIRE AND OVHT/DET/LOOP A1WGL43
121VUAPU/APU/CTL2KDL42
121VUAPU/ECB/SPLY1KDL41
121VUAPU/AUTO/EXTIG/GND/TEST30WFL40
121VUAPU/FIRE/EXTIG/SQUIB/B2WFL39
121VUAPU/FIRE/EXTIG/SQUIB/A1WFL38
121VUAPU/FIRE/LP VALVE/NORM4WFM42
121VUAPU/FIRE/LP VALVE/STBY3WFM41
121VUAPU/FUEL/LP VALVE/CTL1QFM40
121VUAPU/FUEL/LP VALVE/SPLY2QFM39
121VUAPU/FUEL/PUMP/CTL3QCM38
4. Procedure
Subtask 49-00-00-710-057-B ** ON A/C NOT FOR ALL
WARNING: MAKE SURE THAT THE FWD AVIONICS ACCESS DOOR 811 IS OPEN WITH A WARNING PLACARD ATTACHED TO IT. THE WARNING NOTICE MUST TELL PERSONS NOT TO CLOSE THE DOOR. THIS PREVENTS ACCIDENTAL PRESSURIZATION OF THE AIRCRAFT.
CAUTION: DO NOT USE THE APU DURING FLUID DE-ICING OPERATIONS. DE-ICING FLUID CAN CONTAMINATE THE INSIDE OF THE APU.
CAUTION: DO NOT START OR TRY TO START THE APU MORE THAN THREE TIMES, ONE AFTER THE OTHER. AFTER THE THIRD TIME, THERE MUST BE A MINIMUM OF ONE HOUR BEFORE YOU START OR TRY TO START THE APU AGAIN. THIS MAKES SURE THAT THE TEMPERATURE OF THE STARTER MOTOR DECREASES SUFFICIENTLY.
A. Operational Test of the APU
ACTION
RESULT
1.On the panel 35VU:
  • Push the BAT1 and BAT2 pushbutton switches in the AUTO position.
On the panel 35VU:
  • DC V battery indicators show each battery voltage (28V maximum, 21V minimum).
2.On the panel 11VU:
  • Push the BLEED pushbutton switch on the ECAM panel.
On the ECAM panel display:
  • The BLEED system page comes on.
3.On the panel 30VU:
  • Push the APU BLEED pushbutton switch to the OFF position.
On the panel 30VU:
  • The ON legend in the APU BLEED pushbutton switch goes off.
4.On the panel 30VU:
  • Set the X BLEED switch to the AUTO position.
On the lower ECAM display:
  • The X BLEED valve is in the closed position.
5.On the panel 40VU:
  • Push the fuel X FEED pushbutton switch to the CLOSED position.
On the panel 40VU:
  • The ON legend in the fuel X FEED pushbutton switch goes off.
6.On the panel 11VU:
  • Push the APU pushbutton switch on the ECAM panel.
On the ECAM panel display:
  • APU systems page comes on.
7.On the panel 25VU:
  • Push the APU MASTER SW pushbutton switch to the ON position.
On the panel 25VU:
  • The ON legend in the APU MASTER SW comes on.
NOTE: The MASTER SW FAULT legend could come on if the Battery Charge Limiter does a power-up test after A/C power loss. Wait 45 seconds, recycle the APU MASTER SW then continue with the start sequence.
NOTE: Wait 5 seconds before power-up and monitor that the phases are completed.
8.On the panel 25VU:
  • Push the APU START pushbutton switch to the ON position.
On the panel 25VU:
  • The ON legend in the APU START pushbutton switch comes on.

On the lower ECAM display:
  • N indication increases.
9.On the lower ECAM display:
  • Do a check at 7% N.
On the lower ECAM display:
  • N% indication increases.
  • EGT increases.
  • Monitor the acceleration.
  • Continuous increase of EGT and N indications.
  • Do a check at 100% N.
On the panel 25VU:
  • The ON legend in the START pushbutton switch is off.
  • The AVAIL legend in the START pushbutton switch is on.

On the lower ECAM display:
  • AVAIL indication is on.
  • EGT in limits.
  • N indication shows 100% N.
  • APU GEN (amber) OFF (white) indication is on.
  • The APU bleed valve symbol is in closed position.
10.On the panel 35VU:
  • Push the APU GEN pushbutton switch to the ON position.
On the panel 35VU:
  • The APU GEN pushbutton switch OFF legend goes off.

On the lower ECAM display:
  • The generator load, voltage and frequency indications are in the specified limits (no amber or red indications).
11.On the panel 30VU:
  • Push the APU BLEED pushbutton switch to the ON position.
On the panel 30VU:
  • The APU BLEED pushbutton switch ON legend comes on.

On the lower ECAM display:
  • Momentarily there is a small increase in EGT.
  • The APU bleed valve symbol is in open position.
  • The APU bleed pressure indication shows that the bleed pressure has increased.
12.On the panel 30VU:
  • Push the PACK1 and PACK2 pushbutton switches to the ON position.
On the panel 30VU:
  • The OFF legends in the PACK1 and PACK2 pushbutton switches go off.

On the lower ECAM display:
  • The N indication stays at 100%.
  • The EGT indication changes to the pneumatic load condition.
  • All indications show that the APU operates in the specified limits (no amber or red indications).
On the panel 35VU:
  • Push the APU GEN pushbutton switch to the OFF position.
On the panel 35VU:
  • The APU GEN pushbutton switch OFF legend comes on.

On the lower ECAM display:
  • APU GEN (amber) OFF (white) indication comes on.
13.On the panel 30VU:
  • Push the PACK1 and PACK2 pushbutton switches to the OFF position.
On the panel 30VU:
  • The OFF legends in the PACK1 and PACK2 pushbutton switches come on.

On the lower ECAM display:
  • The N indication stays at 100%.
  • The EGT indication changes to the no pneumatic load condition.
14.On the panel 30VU:
  • Push the APU BLEED pushbutton switch to the OFF position.
On the panel 30VU:
  • The ON legend in the APU BLEED pushbutton switch goes off.
15.On the panel 25VU:
  • Release the APU MASTER SW pushbutton switch.
On the panel 25VU:
  • The ON legend in the APU MASTER SW pushbutton switch goes off.
  • The AVAIL legend in the APU START pushbutton switch stays on during the APU cooldown delay of 2 minutes, it goes off after the APU cooldown delay is completed.

On the lower ECAM display:
  • APU BLEED valve symbol changes to the closed position.

On the lower ECAM display:
  • The AVAIL indication goes off, when the AVAIL legend in the APU START pushbutton switch goes off.
  • The EGT and N indications go off, when the ECB is powered down.
16.On the MCDU 1(2) AVIONICS STATUS page:
  • There is no APU related indication.

NOTE: You must wait 2 minutes after the AVAIL legend goes off before you select BAT 1and BAT 2 to the OFF position. This gives sufficient time for the air intake to fully close.

5. Close-up
Subtask 49-00-00-860-076-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
   (1) On the MCDU 1(2):
  • Push the line key adjacent to the RETURN indication until the MCDU MENU page comes on.
  • Set the BRT knob to off.
   (2) Make sure that the hydraulic system has returned back to the previous configuration (Ref. AMM TASK 29-00-00-864-001).
   (3) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).
   (4) Make sure that the work area is clean and clear of tools and other items.
   (5) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
[Rev.10 from 2021] 2026.04.01 04:05:02 UTC