Loss of the Radio Altimeter Indication during Approach

TASK 34-42-00-810-842-A
Loss of the Radio Altimeter Indication during Approach

1. Possible Causes

signs of water and corrosion in the connectors of the antennas
signs of water and corrosion in the coaxial lines of the antennas
RA reception and transmission antennas

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ESPM 2053230
AMM 34-42-00-740-002	BITE Test of the Radio Altimeter
AMM 34-42-11-000-001	Removal of the Radio Altimeter Antenna
AMM 34-42-11-400-001	Installation of the Radio Altimeter Antenna
AMM 34-42-11-920-001	Radio Altimeter Antennas and Coaxial Cables Replacement

3. Fault Confirmation
Subtask 34-42-00-740-114-A

A. Test
Do the BITE test of the RA transceivers 1 and 2 AMM 34-42-00-740-002.

4. Fault Isolation
Subtask 34-42-00-810-096-A

A. If the tests are OK:

remove the RA reception antennas (5SA1), (5SA2), and the RA transmission antennas (6SA1), (6SA2) AMM 34-42-11-000-001
do a check for signs of water and corrosion in the connectors of the antennas
do a check for signs of water and corrosion in the coaxial lines of the antennas
repair the coaxial lines if necessary ESPM 2053230.
If the fault continues:
replace the RA reception and transmission antennas related to the defective system(s) AMM 34-42-11-000-001 and AMM 34-42-11-400-001.

Subtask 34-42-00-810-113-A

B. If the fault continues:

replace the coaxial cable 4602VB and 4604VB AMM 34-42-11-920-001.

5. Close-up
Subtask 34-42-00-740-115-A

A. Do the test given in para. 3.
Put the aircraft back to its initial configuration.
After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:33:11 UTC