Message Name:

INTERNAL FAULT

Message Code:

B3-006747

Associated CAS:

FIREX APU SQUIB FAIL
(Caution)

APU FIRE DET FAIL
(Caution)

R FIRE DET FAIL
(Caution)

CARGO SMOKE DET FAIL
(Caution)

FIRE SYS FAULT
(Caution)

L FIRE DET FAIL
(Caution)

GEAR BAY DET FAIL
(Caution)

FIREX BTL 1 LOW
(Advisory)

FIREX BTL 1 FAULT
(Advisory)

FIREX BTL 2 LOW
(Advisory)

FIREX BTL 2 FAULT
(Advisory)

Reporting LRU:	FIREX CTRL UNIT
System Description:	26-11-00
Schematic Diagram:	26-11-00
Wiring Diagram:	26-11-05

An internal fault to the FIREX Control Unit has been detected.

• Missing 28 VDC input or ground to FIREX CU
• Temperature is too high
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW300-26-0249 - Landing GEAR BAY DET FAIL EICAS Message (20003 - 20500)

Forum Articles/Infoservice/Newsletter: None

Removal of the Fire-Detection-and-Extinguishing (FIREX) Control-Unit	AMM 26-11-01-000-801
Installation of the Fire-Detection-and-Extinguishing (FIREX) Control-Unit	AMM 26-11-01-400-801
Wiring - Maintenance Practices - ALL	SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL	SPM 20-12-10-02

1. Reset FIREX Control Unit (A91) circuit breakers CB5-A3, CB6-A4, CB1-A11 and CB2-A11. Check MDC for fault.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

2. Measure for 28 VDC at 91P1 pins 1, 3 and 91P2 pins 1, 3. Repair as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

3. Measure for GND signal at 91P1 pins 9, 15, 63 and 91P2 pins 9, 15, 63. Repair as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

4. Replace FIREX control unit.
5. Do close out.