Loss of the Reception of the BSCU 2 VALID Discretes by one FMGC

TASK 22-83-00-810-849-A
Loss of the Reception of the BSCU 2 VALID Discretes by one FMGC

1. Possible Causes

FMGC-1 [1CA1]
BSCU [10GG]
wiring of the BSCU OPP VALID COM and BSCU OPP VALID MON discretes (from the FMGC 1 (1CA1) to the BSCU (10GG))
FMGC-2 [1CA2]
wiring of the BSCU OWN VALID COM and BSCU OWN VALID MON discretes (from the FMGC 2 (1CA2) to the first terminal block)

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 228504
AMM 22-91-00-710-001	Ground Scanning of the AFS
AMM 32-42-34-000-001	Removal of the Braking/Steering Control Unit (BSCU)
AMM 32-42-34-400-001	Installation of the Braking/Steering Control Unit (BSCU)

3. Fault Confirmation
Subtask 22-83-00-865-076-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	HYDRAULIC/BRAKING AND STEERING/SYS2/SPLY	4GG	M36
121VU	HYDRAULIC/BRAKING AND STEERING/SYS2/CTL	3GG	M35
121VU	HYDRAULIC/BRAKING AND STEERING/SYS1/CTL	1GG	M34
121VU	HYDRAULIC/BRAKING AND STEERING/SYS1/IND AND/SPLY	2GG	M33

Subtask 22-83-00-710-130-A

B. Test

NOTE: If the fault message AFS: BSCU2 is shown on the post flight report after in-flight or on ground reset of the anti skid and nose wheel steering system with the A/SKID & NOSE WHEEL control switch (5 GG):

no maintenance action required.

(1) Open the circuit breakers 1GG and 2GG.
(2) Do the Ground Scanning of the AFS AMM 22-91-00-710-001.
(3) Close the circuit breakers 1GG and 2GG.

4. Fault Isolation
Subtask 22-83-00-810-128-A

A. If the test gives the maintenance message AFS: BSCU2 (ISSUED BY: FG1):

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

(1) If the fault continues:

replace the BSCU [10GG] AMM 32-42-34-000-001 and AMM 32-42-34-400-001.

(2) If the fault continues:

do a check and repair the wiring of the BSCU OPP VALID COM and BSCU OPP VALID MON discretes (from the FMGC 1 (1CA1) to the BSCU (10GG)) ASM 228504.

Subtask 22-83-00-810-129-A

B. If the test gives the maintenance message AFS: BSCU2 (ISSUED BY: FG2):

replace the FMGC-2 [1CA2] AMM 22-83-34-000-001 and AMM 22-83-34-400-001.

(1) If the fault continues:

do a check and repair the wiring of the BSCU OWN VALID COM and BSCU OWN VALID MON discretes (from the FMGC 2 (1CA2) to the first terminal block) ASM 228504.

Subtask 22-83-00-710-131-A

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:25:32 UTC