Loss of the MDDU

TASK 31-38-00-810-809-A
Loss of the MDDU

1. Possible Causes

CMPTR-TCAS [1SG]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AWM 313802
AWM 313805
AMM 34-43-34-000-001	Removal of the TCAS Computer
AMM 34-43-34-400-001	Installation of the TCAS Computer

3. Fault Confirmation
Subtask 31-38-00-740-052-A ** ON A/C NOT FOR ALL

A. Not applicable, the fault is evident.

4. Fault Isolation
Subtask 31-38-00-810-058-A ** ON A/C NOT FOR ALL

A. If the fault is identified by the crew observation:

UNIT FAIL (0400) is displayed on the MDDU display

(1) replace the CMPTR-TCAS [1SG] AMM 34-43-34-000-001 and AMM 34-43-34-400-001.
(2) If the fault continues:
(a) Do a check and repair if necessary the wiring between:

the pins A/50, 51, 52 and 53 of the MDDU (1TD) and the pins B/23, 22, 21 and 20 of the DLRB (102TD) AWM 313802,
the pins B/36, 37 and 38 of the DLRB (102TD) and the pins AF/6D, 6C and 6B of the TCAS (1SG) AWM 313805.

[Rev.8 from Aug 2018] 2026.04.04 04:30:08 UTC