Loss of the FCU 1 Channel A Output Bus by the DMC 3

TASK 31-63-00-810-946-A
Loss of the FCU 1 Channel A 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 31-63-00-865-178-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AUTO FLT/FCU/1	9CA1	B05

Subtask 31-63-00-740-302-A ** ON A/C NOT FOR ALL

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

Subtask 31-63-00-740-302-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 31-63-00-810-194-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message DMC 3 : NO FCU 1A DATA:

(1) If the fault continues:

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

Subtask 31-63-00-810-194-C ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message FCU1(2CA)BUS FCU1A/DMC3(1WT3):

(1) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pins AA/6A, 6B to the first terminal block ASM 316201.

Subtask 31-63-00-740-303-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:40:07 UTC