Loss of the Bus Output from the FDU of the Engine 1 to the CFDIU

TASK 31-32-00-810-814-A
Loss of the Bus Output from the FDU of the Engine 1 to the CFDIU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 26-12-34-000-001	Removal of the Engine Fire-Detection Unit (FDU)
AMM 26-12-34-400-001	Installation of the Engine Fire-Detection Unit (FDU)
AMM 31-32-00-869-002	Procedure for the Class 3 Fault Reading
ASM 313206
AMM 31-32-34-000-001	Removal of the CFDIU
AMM 31-32-34-400-001	Installation of the CFDIU

3. Fault Confirmation
Subtask 31-32-00-865-061-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	ENGINE/1/FIRE DET/LOOP A	7WD1	A06
121VU	ENGINE/ENG1/FIRE DET/LOOP B	8WD1	Q38

Subtask 31-32-00-740-074-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 31-32-00-810-062-A

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

(1) If the fault continues:

(a) If the fault continues:

do a check and repair the wiring from the CFDIU (1TW) to the FDU of the engine 1 (2WD1) from pins AA/14B, 14C to pins A/G,F , ASM 313206.

Subtask 31-32-00-740-075-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:29:48 UTC