Loss of the RA Indication on the CAPT PFD

TASK 34-42-00-810-827-A
Loss of the RA Indication on the CAPT PFD

1. Possible Causes

DMC-1 [1WT1]
wiring of the RA2 INPUT bus from the DMC1 (1WT1) to the first terminal block
wiring of the RA1 INPUT bus from the DMC1 (1WT1) to the first terminal block
XCVR-RA, 1 [2SA1]
wiring of the ALTITUDE BUS 2 from the RA transceiver 1 (2SA1) to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC
AMM 34-42-00-740-002	BITE Test of the Radio Altimeter
ASM 344201
AMM 34-42-33-000-001	Removal of the Radio Altimeter Transceiver
AMM 34-42-33-400-001	Installation of the Radio Altimeter Transceiver

3. Fault Confirmation
Subtask 34-42-00-740-082-A

A. Test
(1) Do the BITE test of the radio altimeter AMM 34-42-00-740-002 and make sure that the radio altitude indication is shown on the CAPT PFD.

4. Fault Isolation
Subtask 34-42-00-810-078-A

A. If the radio altitude indication is not shown on the CAPT PFD:

(1) If the fault continues:

do a check and repair the wiring of the RA2 INPUT bus from the DMC1 (1WT1) to the first terminal block ASM 344201
on the center pedestal, on the SWITCHING panel 8VU, set the EIS DMC selector switch to CAPT 3
make sure that the radio altitude indication is shown on the CAPT PFD.

(a) If the radio altitude indication is shown:

do a check and repair the wiring of the RA1 INPUT bus from the DMC1 (1WT1) to the first terminal block ASM 344201.

(b) If the radio altitude indication is not shown:

1 If the fault continues:

do a check and repair the wiring of the ALTITUDE BUS 2 from the RA transceiver 1 (2SA1) to the first terminal block ASM 344201.

Subtask 34-42-00-740-083-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:10 UTC