Loss of the Two Radio Altimeter Systems

TASK 34-42-00-810-826-A
Loss of the Two Radio Altimeter Systems

1. Possible Causes

XCVR-RA, 1 [2SA1]
XCVR-RA, 2 [2SA2]
wiring of the ALTITUDE BUS 2 from the RA transceiver 1 (2SA1) to the first terminal block
wiring of the ALTITUDE BUS 2 from the RA transceiver 2 (2SA2) to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-42-00-740-002	BITE Test of the Radio Altimeter
ASM 344201
ASM 344202
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 34-42-00-740-080-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 two PFDs.

4. Fault Isolation
Subtask 34-42-00-810-077-A

A. If on the two PFDs the radio altitude indication is not shown and the red RA flag comes into view:

(1) If the fault continues:

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

(a) If there is no continuity:

(b) If there is continuity:

do a check and repair the wiring of the ALTITUDE BUS 2 from the RA transceiver 2 (2SA2) to the first terminal block ASM 344202.

Subtask 34-42-00-740-081-A

B. Do the test given in Para. 3.

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