Failure of the ATSU

TASK 31-32-00-810-941-A
Failure of the ATSU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-32-00-740-009	Read the AVIONICS STATUS on the MCDU
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 31-32-00-865-175-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	ATSU 1	3TX1	L16
121VU	ATSU 1/SWTG	5TX1	L15

Subtask 31-32-00-740-313-A

B. Read the AVIONICS STATUS on the MCDU AMM 31-32-00-740-009.

4. Fault Isolation
Subtask 31-32-00-810-194-A

A. If the test gives the maintenance message NO ATSU DATA:
(1) replace the ATSU [1TX1] AMM 46-21-34-000-001 and AMM 46-21-34-400-001.

Subtask 31-32-00-869-052-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:29:59 UTC