DOC AIRBUS | TSM A320FAPU Master Switch ON Legend inoperative (131-9(A))
TASK 49-00-81-810-897-A
APU Master Switch ON Legend inoperative (131-9(A))
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 49-00-81-710-244-A ** ON A/C NOT FOR ALL
Subtask 49-00-81-810-162-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:34:39 UTC
APU Master Switch ON Legend inoperative (131-9(A))
1. Possible Causes
- bulbs
- aircraft wiring
- P/BSW-APU/MASTER SW [14KD]
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 33-14-00-810-801-A | Failure of One Annunciator Light Only |
| AMM 33-14-00-710-001 | Operational Test of the Lights |
| ASM 496101 |
Subtask 49-00-81-710-244-A ** ON A/C NOT FOR ALL
A. Test
(1) Push the APU Master SW p/bsw and check that the ON legend comes on.
(2) Release the APU Master SW p/bsw.
4. Fault Isolation(1) Push the APU Master SW p/bsw and check that the ON legend comes on.
(2) Release the APU Master SW p/bsw.
Subtask 49-00-81-810-162-A ** ON A/C NOT FOR ALL
A. If the ON legend is off:
Subtask 49-00-81-710-245-A ** ON A/C NOT FOR ALL - do the Operational Test of the Annunciator Light Test System in the Cockpit AMM 33-14-00-710-001.
- replace the bulbs .
- do the trouble shooting of the anunciator light test system (Ref. TSM TASK 33-14-00-810-801).
- do a check for a GND signal at the APU Master SW p/bsw (14KD) A/C1 ASM 496101.
- repair the aircraft wiring .
- replace the P/BSW-APU/MASTER SW [14KD] .
B. Do the test given in Para. 3.