Loss of the AP INST DISC Discretes on the FMGC 1

TASK 22-83-00-810-807-A
Loss of the AP INST DISC Discretes on the FMGC 1

1. Possible Causes

FMGC-1 [1CA1]
wiring of the AP INST DISC NO discrete (from the FMGC 1 (1CA1) to the takeover and priority relay (47CE1)
wiring of the GND FILTERED discrete (from the FMGC 1 (1CA1) to the takeover and priority relay (47CE1))
RELAY-TAKEOVER & PRIORITY 1 [47CE1]
wiring of the AP INST DISC NC discrete (from the FMGC 1 (1CA1) to the takeover and priority relay (47CE1))
wiring of the takeover and priority relay (47CE1)

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 22-83-00-710-062-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 1:
(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 22-83-00-810-056-B

A. If only the first test gives the maintenance message AFS: FMGC1/TAKE OV CKT:

replace the FMGC-1 [1CA1] , AMM 22-83-34-000-001 and AMM 22-83-34-400-001.

(1) If the fault continues:

do a check of the wiring of the AP INST DISC NO discrete (from the FMGC 1 (1CA1) to the takeover and priority relay (47CE1) 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 1 (1CA1) to the takeover and priority relay (47CE1)) ASM 228503.

1 If there is no continuity:

repair the above wiring.

2 If there is continuity:

replace the RELAY-TAKEOVER & PRIORITY 1 [47CE1] .

Subtask 22-83-00-810-057-B

B. If only the second test gives the maintenance message AFS: FMGC1/TAKE OV CKT:

replace the FMGC-1 [1CA1] , AMM 22-83-34-000-001 and AMM 22-83-34-400-001.

(1) If the fault continues:

do a check of the wiring of the AP INST DISC NC discrete (from the FMGC 1 (1CA1) to the takeover and priority relay (47CE1)) 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 (47CE1) (from 47CE1 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 1 [47CE1] .

Subtask 22-83-00-710-063-A

C. Do the tests given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:25:29 UTC