W DOC AIRBUS | TSM A320F

Loss of the AP INST DISC Discretes on the FMGC 2

TASK 22-83-00-810-808-A
Loss of the AP INST DISC Discretes on the FMGC 2

1. Possible Causes
  • FMGC-2 [1CA2]
  • wiring of the AP INST DISC NO discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2))
  • wiring of the GND FILTERED discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2))
  • RELAY-TAKEOVER & PRIORITY 2 [47CE2]
  • wiring of the AP INST DISC NC discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2))
  • wiring of the takeover and priority relay (47CE2)
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 22-83-34-000-001
Removal of the FMGC
AMM 22-83-34-400-001
Installation of the FMGC
ASM 228503
AMM 22-96-00-710-001
Operational Test of the AFS
3. Fault Confirmation
Subtask 22-83-00-710-064-A
A. Test
   (1) On the FCU, make sure that the two AP pushbutton switches are pushed.
   (2) Do the operational tests of the AFS AMM 22-96-00-710-001 and read the result for the FMGC 2:
     (a) With one takeover and priority pushbutton switch pushed (on side stick).
     (b) With the two takeover and priority pushbutton switches released.
4. Fault Isolation
Subtask 22-83-00-810-059-B
A. If only the first test gives the maintenance message AFS: FMGC2/TAKE OV CKT:
   (1) If the fault continues:
  • do a check of the wiring of the AP INST DISC NO discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2)) ASM 228503.
     (a) If there is no continuity:
  • repair the above wiring.
     (b) If there is continuity:
  • do a check of the wiring of the GND FILTERED discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2)) ASM 228503.
       1 If there is no continuity:
  • repair the above wiring.
       2 If there is continuity:
  • replace the RELAY-TAKEOVER & PRIORITY 2 [47CE2] .
Subtask 22-83-00-810-060-B
B. If only the second test gives the maintenance message AFS: FMGC2/TAKE OV CKT:
   (1) If the fault continues:
  • do a check of the wiring of the AP INST DISC NC discrete (from the FMGC 2 (1CA2) to the takeover and priority relay (47CE2)) ASM 228503.
     (a) If there is no continuity:
  • repair the above wiring.
     (b) If there is continuity:
  • do a check of the wiring of the takeover and priority relay (47CE2) (from 47CE2 pin A/D to the first terminal block) ASM 228503.
       1 If there is no continuity:
  • repair the above wiring.
       2 If there is continuity:
  • replace the RELAY-TAKEOVER & PRIORITY 2 [47CE2] .
Subtask 22-83-00-710-065-A
C. Do the tests given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:25:29 UTC
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