Loss of the FCU 2 Channel B Output Bus by the DMC 3

TASK 31-63-00-810-951-A
Loss of the FCU 2 Channel B Output Bus by the DMC 3

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-60-00-740-002	Perform Electronic Instrument System (EIS) Input Test
AMM 31-60-00-740-007	GROUND SCANNING Test of the DMC
ASM 316201
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC

3. Fault Confirmation
Subtask 31-63-00-865-183-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	AUTO FLT/FCU/2	9CA2	M21

Subtask 31-63-00-740-312-A ** ON A/C NOT FOR ALL

B. Test
Do the EIS input test AMM 31-60-00-740-002.

Subtask 31-63-00-740-312-B ** ON A/C NOT FOR ALL

B. Test
Do the Ground Scanning Test of the DMC AMM 31-60-00-740-007.

4. Fault Isolation
Subtask 31-63-00-810-199-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message DMC 3 : NO FCU 2B DATA:

(1) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pins AA/2F, 2G to the first terminal block ASM 316201.

Subtask 31-63-00-810-199-C ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message FCU2(2CA)BUS FCU2B/DMC3(1WT3):

(1) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pins AA/1G, 1H to the first terminal block ASM 316201.

Subtask 31-63-00-740-313-A

B. Do the test given in Para. 3.B.

[Rev.8 from Aug 2018] 2026.04.04 04:30:48 UTC