DOC AIRBUS | AMM A320FTest of the Clutch of the APU Starter Motor (131-9(A))
TASK 49-42-51-700-002-A
Test of the Clutch of the APU Starter Motor (131-9(A))
This AMM task is also used for other maintenance purposes.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 49-42-51-860-073-A ** ON A/C NOT FOR ALL
Subtask 49-42-51-210-060-A ** ON A/C NOT FOR ALL
Subtask 49-42-51-410-065-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 12:43:08 UTC
Test of the Clutch of the APU Starter Motor (131-9(A))
WARNING:
DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).
WARNING:
MAKE SURE THAT YOU HAVE THE CORRECT FIRE FIGHTING EQUIPMENT AVAILABLE.
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.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
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 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.
1. Reason for the JobThis AMM task is also used for other maintenance purposes.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| No specific | 1 | SOCKET DIA 5/16 IN - HEXAGONAL |
| No specific | AR | WARNING NOTICE(S) |
| No specific | 1 | WRENCH 1/4 IN - RATCHET |
| 98L12003001000 | AR | HARNESS,SAFETY |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.08BBB1) | Non Aqueous Cleaner-- Petroleum Based - |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 315 | TAIL CONE APU AND ACCESSORY COMPARTMENT |
| 316 | TAIL CONE APU AND ACCESSORY COMPARTMENT |
| 315AL, 316AR |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 24-42-00-861-001-A | Energize the Ground Service Network from the External Power |
| TASK 24-42-00-862-001-A | De-energize the Ground Service Network Supplied from the External Power |
| TASK 29-00-00-864-001-A | Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action |
| TASK 49-00-00-860-008-A | APU Start by External Power |
| TASK 49-00-00-860-008-A-01 | APU Start by Batteries |
| TASK 49-00-00-860-009-A | APU Shutdown by External Power (131-9(A)) |
| TASK 49-00-00-860-009-A-01 | APU Shutdown by Batteries (131-9(A)) |
| TASK 49-42-51-000-006-A | Removal of the Starter Motor (131-9(A)) |
| TASK 49-42-51-400-006-A | Installation of the Starter Motor (131-9(A)) |
| TASK 49-42-52-000-003-A | Removal of the Starter Motor Clutch (131-9(A)) |
| TASK 49-42-52-400-003-A | Installation of Starter Motor Clutch (131-9(A)) |
| TASK 52-41-00-010-001-A | Open the APU Doors for Access |
| TASK 52-41-00-410-001-A | Close the APU Doors after Access |
| TSM 49-00-81-810-834 | APU AUTO SHUTDOWN - NO ACCELERATION, Starter Motor Fault (131-9(A)) |
Starter-Motor Brush-Wear Indicator (131-9(A))Subtask 49-42-51-860-073-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On overhead panel 25VU, make sure that the APU MASTER SW pushbutton switch is released (the ON legend is off).
(3) On the APU section of overhead panel 25VU, put the WARNING NOTICE(S) in position to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
Subtask 49-42-51-865-075-A ** ON A/C NOT FOR ALL (1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On overhead panel 25VU, make sure that the APU MASTER SW pushbutton switch is released (the ON legend is off).
(3) On the APU section of overhead panel 25VU, put the WARNING NOTICE(S) in position to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
B. Open, safety and tag this(these) circuit breaker(s):
Subtask 49-42-51-010-067-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/APU/CTL | 2KD | L42 |
| 121VU | APU/ECB/SPLY | 1KD | L41 |
C. Get Access
(2) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below APU access doors 315AL and 316AR.
(3) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(4) Set the light switch 11LJ to the ON position.
4. ProcedureWARNING:
BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.
(1) Put on and attach the HARNESS, SAFETY before you start work in the work area.(2) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below APU access doors 315AL and 316AR.
(3) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(4) Set the light switch 11LJ to the ON position.
Subtask 49-42-51-210-060-A ** ON A/C NOT FOR ALL
A. Inspection of the brush indicator of the Starter Motor.
(1) If necessary, clean the brush-wear indicator area with Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
(2) Do a visual check of the brush-wear indicator pin (2) position.
(a) If you cannot see the brush-wear indicator pin (2):
Subtask 49-42-51-710-052-A ** ON A/C NOT FOR ALL (1) If necessary, clean the brush-wear indicator area with Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) .
(2) Do a visual check of the brush-wear indicator pin (2) position.
(a) If you cannot see the brush-wear indicator pin (2):
- Replace the starter motor (Ref. AMM TASK 49-42-51-000-006) and (Ref. AMM TASK 49-42-51-400-006).
- Replace the starter motor (Ref. AMM TASK 49-42-51-000-006) and (Ref. AMM TASK 49-42-51-400-006).
B. Test of the Starter Motor
(2) Remove the starter-motor drive-shaft cover (1).
(a) Make sure that:
(a) Make sure that:
(6) If the clutch does not engage or disengage correctly, replace the starter motor clutch (Ref. AMM TASK 49-42-52-000-003) and (Ref. AMM TASK 49-42-52-400-003).
(7) Install the starter-motor drive-shaft cover (1).
(8) Set the light switch 11LJ to the OFF position.
(9) Start and operate the APU (Ref. AMM TASK 49-00-00-860-008).
(10) Listen for unusual noises after the starter motor is disengaged at 50% of the APU speed.
(11) Stop the APU (Ref. AMM TASK 49-00-00-860-009).
(12) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(13) Set the light switch 11LJ to the ON position.
(14) Examine the starter motor area for oil leaks:
(a) If you find leaks, replace the starter motor (Ref. AMM TASK 49-42-51-000-006) and (Ref. AMM TASK 49-42-51-400-006).
5. Close-upNOTE: The test procedure that follows is not applicable, if you replaced the starter motor at Paragraph 4. A. Step (2).
(1) Get access to the starter motor drive-shaft.(2) Remove the starter-motor drive-shaft cover (1).
CAUTION:
IF YOU FEEL INTERFERENCE WHILE YOU TURN THE STARTER-MOTOR MANUAL DRIVE-SHAFT, DO NOT APPLY TOO MUCH FORCE. TOO MUCH FORCE CAN CAUSE DAMAGE TO THE STARTER-MOTOR MANUAL DRIVE-SHAFT.
(3) Turn the starter-motor manual drive-shaft with the SOCKET DIA 5/16 IN - HEXAGONAL and the WRENCH 1/4 IN - RATCHET in the direction of the arrow shown on the starter motor body.(a) Make sure that:
- The starter-motor manual drive-shaft turns freely from the APU side.
- The clutch engages to the starter-motor manual drive-shaft.
NOTE: The starter motor clutch engages correctly:
- If it engages immediately
- If it does not rub
- If it does not make an unusual noise.
CAUTION:
IF YOU FEEL INTERFERENCE WHILE YOU TURN THE STARTER-MOTOR MANUAL DRIVE-SHAFT, DO NOT APPLY TOO MUCH FORCE. TOO MUCH FORCE CAN CAUSE DAMAGE TO THE STARTER-MOTOR MANUAL DRIVE-SHAFT.
(4) Turn the starter-motor manual drive-shaft with the SOCKET DIA 5/16 IN - HEXAGONAL and the WRENCH 1/4 IN - RATCHET in the opposite direction of the arrow shown on the starter motor body.(a) Make sure that:
- The starter-motor manual drive-shaft turns freely from the APU side.
- The clutch disengages from the starter-motor manual drive-shaft.
NOTE: The starter motor clutch disengages correctly:
(5) If the starter-motor manual drive-shaft does not turn freely, do the troubleshooting procedure TSM 49-00-81-810-834.- If it disengages immediately
- If the starter-motor manual drive-shaft turns freely in the opposite direction of the arrow
- If it does not rub
- If it does not make an unusual noise.
(6) If the clutch does not engage or disengage correctly, replace the starter motor clutch (Ref. AMM TASK 49-42-52-000-003) and (Ref. AMM TASK 49-42-52-400-003).
(7) Install the starter-motor drive-shaft cover (1).
(8) Set the light switch 11LJ to the OFF position.
(9) Start and operate the APU (Ref. AMM TASK 49-00-00-860-008).
(10) Listen for unusual noises after the starter motor is disengaged at 50% of the APU speed.
(11) Stop the APU (Ref. AMM TASK 49-00-00-860-009).
(12) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(13) Set the light switch 11LJ to the ON position.
(14) Examine the starter motor area for oil leaks:
(a) If you find leaks, replace the starter motor (Ref. AMM TASK 49-42-51-000-006) and (Ref. AMM TASK 49-42-51-400-006).
NOTE: No leaks are permitted.
Subtask 49-42-51-410-065-A ** ON A/C NOT FOR ALL
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the light switch 11LJ to the OFF position.
(3) Close APU access doors 316AR and 315AL (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the 98L12003001000 HARNESS,SAFETY.
(5) Remove the access platform(s).
Subtask 49-42-51-865-076-A ** ON A/C NOT FOR ALL (1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the light switch 11LJ to the OFF position.
(3) Close APU access doors 316AR and 315AL (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the 98L12003001000 HARNESS,SAFETY.
(5) Remove the access platform(s).
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 49-42-51-860-074-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | APU/APU/CTL | 2KD | L42 |
| 121VU | APU/ECB/SPLY | 1KD | L41 |
C. Put the aircraft back to its initial configuration.
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(2) Remove the WARNING NOTICE(S).
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(2) Remove the WARNING NOTICE(S).