Loss of the FIRE TEST (LOOP A) Discrete Input from the Engine 1 FDU

TASK 26-12-00-810-827-A
Loss of the FIRE TEST (LOOP A) Discrete Input from the Engine 1 FDU

1. Possible Causes

ENG/APU FIRE PNL [1WD]
wiring of the 28VDC signal from the circuit breaker (7WD1) to the ENG/APU FIRE panel (1WD)
wiring of the FIRE TEST (LOOP A) discrete from the engine 1 FDU (2WD1) to the ENG/APU FIRE panel (1WD)

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 26-12-00-710-001	Operational Check of Loop/Squib
ASM 261202
AMM 26-12-12-000-001	Removal of the ENG/APU Fire Panel
AMM 26-12-12-400-001	Installation of the ENG/APU Fire Panel

3. Fault Confirmation
Subtask 26-12-00-710-100-A

A. Test
(1) Do the operational test of the engine fire and overheat detection (loop/squib) AMM 26-12-00-710-001.

4. Fault Isolation
Subtask 26-12-00-810-080-A

A. If the ENG 1 FIRE indication does not come into view on the upper ECAM DU and if the FIRE legend of the ENG 1 annunciator does not come on on the ENG panel 115VU:

do a check to see if the DISCH legend of the ENG 1/AGENT 1 pushbutton switch on the ENG/APU FIRE panel (1WD) comes on during the fire test.

(1) If the DISCH legend does not come on:

replace the ENG/APU FIRE PNL [1WD] AMM 26-12-12-000-001 and AMM 26-12-12-400-001.

(a) If the fault continues:

do a check and repair the wiring of the 28VDC signal from the circuit breaker (7WD1) to the ENG/APU FIRE panel (1WD), pin A/M ASM 261202.

(2) If the DISCH legend comes on:

replace the ENG/APU FIRE PNL [1WD] AMM 26-12-12-000-001 and AMM 26-12-12-400-001.

(a) If the fault continues:

do a check and repair the wiring of the FIRE TEST (LOOP A) discrete from the engine 1 FDU (2WD1) to the ENG/APU FIRE panel (1WD) ASM 261202.

Subtask 26-12-00-710-101-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:27:10 UTC