W DOC AIRBUS | AMM A320F

APU Start by Batteries

TASK 49-00-00-860-005-A-01
APU Start by Batteries

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: DISCONNECT THE LOW-TENSION ELECTRICAL SUPPLY 6 MINUTES BEFORE YOU START WORK ON THE IGNITION SYSTEM. THE HIGH CURRENT AND VOLTAGE WHICH ARE USED IN THE IGNITION SYSTEM CAN KILL YOU.
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 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: DO NOT TRY TO START THE APU AGAIN DURING A REFUEL/DEFUEL PROCEDURE AFTER AN AUTOMATIC SHUTDOWN OR FAILED APU START. IF YOU DO, THERE IS A RISK OF INJURY AND/OR DAMAGE.
CAUTION: OBEY THE SAFETY PRECAUTIONS.
ZONE: 210
ZONE: 310
FIN: 4005KM ** ON A/C NOT FOR ALL
1. Reason for the Job
Start and operate the APU to do maintenance tasks.
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
SAFETY CLIP - CIRCUIT BREAKER
No specific
1
WARNING NOTICE(S)
 B. Work Zones and Access Panels
ZONE/ACCESS
ZONE DESCRIPTION
210
CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
310
FUSLG TAIL SECTION AFT OF AFT PRESS BHD
811
 C. Referenced Information
REFERENCE
DESIGNATION
TASK 12-33-21-618-001-A
Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Available)
TASK 12-33-21-618-001-A-01
Pre-conditioning through the HP Ground Connection
TASK 12-33-21-618-001-A-02
Pre-conditioning with the APU
TASK 12-33-21-618-001-A-03
Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Not Available)
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 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 49-00-00-941-074-A ** ON A/C NOT FOR ALL
A. Safety Precautions
   (1) Make sure that the danger areas are clear of persons and/or equipment.
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.
   (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 49-00-00-860-130-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) Remove the APU air intake and exhaust blanking plugs.
   (3) On the ELEC section on the panel 35VU:
  • Push the BAT 1 and BAT 2 pushbutton switches in the auto position.
  • Make sure that both batteries are serviceable (the OFF and FAULT legends are off).
   (4) Make sure that there is sufficient fuel in the A/C fuel system.
   (5) 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.
Subtask 49-00-00-865-131-A ** ON A/C NOT FOR ALL
C. Make sure that this(these) circuit breaker(s) is(are) closed:
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/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 49-00-00-875-051-A ** ON A/C NOT FOR ALL
A. Open, safety and tag this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
121VUAPU/AUTO/EXTIG/GND/TEST30WFL40
Subtask 49-00-00-860-230-A ** ON A/C NOT FOR ALL
CAUTION: OBEY THE SAFETY PRECAUTIONS.
B. Start and Operate the APU
NOTE: When the aircraft supply is from the batteries, the test of the APU fire pushbutton-switch shows only the status of fire loop A but not the status of fire loop B.
NOTE: If you must start the APU with the batteries and the Outside Air Temperature (OAT) is 0 deg. C or less, we recommend that you:
  • Select the APU generator to supply aircraft electrical power
  • Start the L1 or L2 main fuel boost-pump.
    You must do this immediately after the APU starts and the AVAIL light comes on. Thus, you will prevent APU AUTO S/D because of air in the APU fuel delivery-line.
NOTE: If the battery voltage is less than 25.5 V, we recommend a battery charging-cycle of approximately 20 minutes.

   (1) Make sure that there is a minimum interval of three seconds between the time you set the APU MASTER SW pushbutton switch to ON and the time you set the APU START pushbutton switch to ON.
   (2) On rear circuit-breaker panel 121VU, make sure that circuit breaker APU AUTO EXTIG GND TEST 30WF (L40) is open.
NOTE: This is necessary to prevent an unwanted automatic fire-extinguisher discharge during the test.
ACTION
RESULT
1.On overhead control and indicator panel 25VU, on the APU section:
  • Push the APU MASTER SW pushbutton (14KD) switch.
On overhead control and indicator panel 25VU, on the APU section:
  • The ON legend of the APU MASTER SW pushbutton switch (14KD) comes on.
2.On overhead panel 20VU, on engine APU FIRE panel 1WD:
On overhead panel 20VU, on engine APU FIRE panel 1WD:
  • Push and hold the APU FIRE TEST pushbutton switch.
  • The APU FIRE light of the APU FIRE pushbutton switch comes on (half-light).
  • The SQUIP/DISCH legend of the AGENT pushbutton switch comes on.
  • Release the APU FIRE TEST pushbutton switch.
  • The APU FIRE light and the SQUIP/DISCH legend go off.
3.On rear circuit-breaker panel 121VU:
  • Close circuit breaker APU AUTO EXTIG GND TEST 30WF (L40).

4.On overhead control and indicator panel 25VU, on the APU section:
  • Push the APU START pushbutton switch (2KA).
On overhead control and indicator panel 25VU, on the APU section:
  • The ON legend of the APU START pushbutton switch (2KA) comes on.
NOTE: The Electronic Control Box (ECB) (59KD) controls and monitors the APU start.
At the end of the APU start sequence:


On overhead control and indicator panel 25VU, on the APU section:
  • The ON legend of the APU START pushbutton switch (2KA) goes off.
  • The AVAIL legend of the APU START pushbutton switch (2KA) comes on.
NOTE: If necessary, the APU generator can energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).
NOTE: If necessary, the APU can supply bleed air for the pre-conditioning (Ref. AMM TASK 12-33-21-618-001).
[Rev.10 from 2021] 2026.04.01 01:25:32 UTC
"Aviabrain" 2025