W DOC AIRBUS | TSM A320F

Failure of the APU Generator

TASK 24-20-00-810-844-A
Failure of the APU Generator

1. Possible Causes
  • GEN-APU [8XS]
  • wiring
  • GCU-APU [1XS]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
ASM 242301
AMM 24-23-34-000-001
Removal of the GCU-APU
AMM 24-23-34-400-001
Installation of the GCU-APU
AMM 24-23-51-000-001
Removal of the APU Generator
AMM 24-23-51-400-001
Installation of the APU Generator
AMM 24-41-00-861-002
Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002
De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 49-91-45-200-002
Discard Lube and Alternator Scavenge Filter Elements (GTCP 36-300)
3. Fault Confirmation
Subtask 24-20-00-700-092-A ** ON A/C NOT FOR ALL
A. Test
Not applicable.
NOTE: As the APU GEN was set to OFF because of a true failure, the fault confirmation is not necessary.
4. Fault Isolation
CAUTION: BEFORE YOU START THE CHECK OF IDG WIRING THAT INCLUDES CONNECTORS, EXAMINE EACH CONNECTOR TO MAKE SURE THAT THERE IS NO CONTAMINATION IN IT. IF YOU FIND CONTAMINATION, CLEAN THE CONNECTOR AND CONNECT IT AGAIN. IF THE FAILURE CONTINUES, DO THE TROUBLE SHOOTING PROCEDURE AS GIVEN BELOW.
Subtask 24-20-00-810-083-A ** ON A/C NOT FOR ALL
A. If the fault symptom is identified by the CFDS message GEN APU (GEN DIODE) and the upper ECAM DU warning APU GEN FAULT:
NOTE: Do the check of the APU alternator and lube-pump oil filters for metal contamination AMM 49-91-45-200-002.
   (1) If the fault continues:
  • do a check of the wiring for short to open between respectively the APU GCU pins C/1, C/5 and the APU generator pins A/9, A/10 ASM 242301.
   (2) If the wiring is not correct:
  • repair it.
   (3) If the wiring is correct:
  • do a check of the wiring for open or short circuit between respectively the APU generator terminals T/1, T/2, T/3 and the APU GLC terminals A/F, A/E, A/D, then between respectively the APU GLC terminals A/D, A/E, A/F and the APU GCU pins B/3A, B/2B, B/1A.
     (a) If the wiring is not correct:
  • repair it.
     (b) If the wiring is correct:
NOTE: Do not remove the APU GCU before you do the other steps of the trouble shooting.
Subtask 24-20-00-810-083-C ** ON A/C NOT FOR ALL
A. If the fault symptom is identified by the CFDS message GEN APU (GEN DIODE) and the upper ECAM DU warning APU GEN FAULT:
NOTE: Do the check of the APU alternator and lube-pump oil filters for metal contamination AMM 49-91-45-200-002.
   (1) If the fault continues:
  • do a check of the wiring for short to open between respectively the APU GCU pins C/1, C/5 and the APU generator pins A/9, A/10 ASM 242301.
     (a) If the wiring is not correct:
  • repair it.
     (b) If the wiring is correct:
  • do a check of the wiring for open or short circuit between:
    . respectively the APU generator terminals T/1, T/2, T/3 and the APU/EXT power contactor module (29XN) pins 7, 8, 9,
    . then respectively the APU/EXT power contactor module (29XN) pins 7, 8, 9 and the APU GCU pins B/3A, B/2B, B/1A.
       1 If the wiring is not correct:
  • repair it.
       2 If the wiring is correct:
NOTE: Do not remove the APU GCU before you do the other steps of the trouble shooting.
Subtask 24-20-00-700-093-A ** ON A/C NOT FOR ALL
B. Make sure that the aircraft electrical circuits operate correctly in APU configuration.
   (1) Energize the aircraft electrical circuits from the APU AMM 24-41-00-861-002.
   (2) De-energize the aircraft electrical circuits from the APU AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:26:13 UTC
"WTRUIB" 2025