DOC AIRBUS | TSM A320FAPU Master Switch ON Legend inoperative
TASK 49-00-00-810-967-A
APU Master Switch ON Legend inoperative
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 49-00-00-710-348-A ** ON A/C NOT FOR ALL
Subtask 49-00-00-810-326-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:34:28 UTC
APU Master Switch ON Legend inoperative
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 |
| ESPM 2053210 | |
| AMM 33-14-00-710-001 | Operational Test of the Lights |
| ASM 496101 |
Subtask 49-00-00-710-348-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 49-00-00-810-326-A ** ON A/C NOT FOR ALL
A. If the ON legend is off:
Subtask 49-00-00-710-349-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 ESPM 2053210.
- replace the P/BSW-APU/MASTER SW [14KD] .
B. Do the test given in Para. 3.