Loss of the ATSU BUS of the FWC2

TASK 31-53-00-810-945-A
Loss of the ATSU BUS of the FWC2

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System
AMM 31-53-34-000-001	Removal of the Flight Warning Computer (FWC)
AMM 31-53-34-400-001	Installation of the Flight Warning Computer (FWC)
AMM 46-21-00-710-001	Operational Test of the ATSU
ASM 462106
AMM 46-21-34-000-001	Removal of the Air Traffic Service Unit (ATSU)
AMM 46-21-34-400-001	Installation of the Air Traffic Service Unit (ATSU)

3. Fault Confirmation
Subtask 31-53-00-710-285-A

A. Do the operational test of the central warning systems (FWC) AMM 31-50-00-710-001.

Subtask 31-53-00-710-346-A

B. Do the operational test of the ATSU AMM 46-21-00-710-001.

4. Fault Isolation
Subtask 31-53-00-810-188-A

A. If the test gives the maintenance message

FWC2: NO DATA FROM ACARS

or

FWC2: NO DATA FROM ATSU:

(1) Replace the FWC-2 [1WW2] AMM 31-53-34-000-001 and AMM 31-53-34-400-001.
(2) Replace the ATSU [1TX1] AMM 46-21-34-000-001 and AMM 46-21-34-400-001.
(3) If the fault continues:

Do a check and repair the wiring from FWC2 (1WW2) pins AE/5E, 5F to the first terminal block ASM 462106.

Subtask 31-53-00-710-286-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:30:21 UTC