Loss of the Bus Output from the BMC 1 to the CFDIU

TASK 31-32-00-810-846-A
Loss of the Bus Output from the BMC 1 to the CFDIU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-32-00-869-002	Procedure for the Class 3 Fault Reading
ASM 313204
AMM 31-32-34-000-001	Removal of the CFDIU
AMM 31-32-34-400-001	Installation of the CFDIU

3. Fault Confirmation
Subtask 31-32-00-865-093-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 1/CTL	3HA1	D12
49VU	AIR BLEED/ENG 1/MONG	2HA1	D11
** ON A/C NOT FOR ALL
49VU	AIR BLEED/ENG 1/CTL	2HA1	D11
122VU	AIR BLEED/ENG 1/MONG	3HA1	Z23

Subtask 31-32-00-740-138-A

B. Test
On the CFDS MENU page, get access to the AVIONICS STATUS page AMM 31-32-00-869-002.

4. Fault Isolation
Subtask 31-32-00-810-094-A

A. If the test gives the maintenance message:
NO BMC 1 DATA:

(1) If the fault continues:

do a check and repair the wiring from the CFDIU (1TW) pins AA/7D, 7E to the first terminal block , ASM 313204.

Subtask 31-32-00-740-139-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:29:51 UTC