Loss of the Altitude Bus 1 of the RA Transceiver 2 Identified by the AFS

TASK 34-42-00-810-806-A
Loss of the Altitude Bus 1 of the RA Transceiver 2 Identified by the AFS

1. Possible Causes

XCVR-RA, 2 [2SA2]
wiring of the ALTITUDE BUS 1 from the RA transceiver 2 (2SA2) to the first terminal block
ANTENNA-RA RCPTN, 2 [5SA2]
ANTENNA-RA XMSN, 2 [6SA2]
coaxial cable

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ESPM 2053230
AMM 22-91-00-710-001	Ground Scanning of the AFS
ASM 344202
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 34-42-33-000-001	Removal of the Radio Altimeter Transceiver
AMM 34-42-33-400-001	Installation of the Radio Altimeter Transceiver

3. Fault Confirmation
Subtask 34-42-00-865-055-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	COM NAV/RAD ALTM/2	1SA2	K12

Subtask 34-42-00-710-052-A

B. Test
(1) Do the ground scanning of the AFS AMM 22-91-00-710-001.

4. Fault Isolation
Subtask 34-42-00-810-057-A

A. If the test gives the maintenance message AFS : R/A2:

(1) If the fault continues:

do a check and repair the wiring of the ALTITUDE BUS 1 from the RA transceiver 2 (2SA2) to the first terminal block ASM 344202.

(a) If the fault continues:

replace the ANTENNA-RA RCPTN, 2 [5SA2] and ANTENNA-RA XMSN, 2 [6SA2] AMM 34-42-11-000-001 and AMM 34-42-11-400-001.

1 If the fault continues:

do a check and replace if necessary the coaxial cable between the XCVR-RA, 2 [2SA2] pin AA/C and the ANTENNA-RA RCPTN, 2 [5SA2] ASM 344202 ESPM 2053230.

2 If the fault continues:

do a check and replace if necessary the coaxial cable between the XCVR-RA, 2 [2SA2] pin AB/C and the ANTENNA-RA XMSN, 2 [6SA2] ASM 344202 ESPM 2053230.

Subtask 34-42-00-710-053-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:07 UTC