W DOC AIRBUS | TSM A320F

Failure of the Radio Altimeter (RA) Transceiver 1

TASK 34-42-00-810-801-A
Failure of the Radio Altimeter (RA) Transceiver 1

1. Possible Causes
  • XCVR-RA, 1 [2SA1]
  • short to ground at the wiring between the circuit breaker (1SA1) and the RA transceiver 1 (2SA1).
  • C/B-COM NAV/RAD ALTM/1
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 31-32-00-810-934-A
Failure of the Digital Links
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 34-42-00-865-050-A
A. Make sure that this(these) circuit breaker(s) is(are) closed:
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
121VUCOM NAV/RAD ALTM/11SA1K11
Subtask 34-42-00-740-050-A
B. Test
   (1) If the circuit breaker (1SA1) trips, refer to Para. 4. C. of this trouble shooting procedure.
   (2) Do the BITE test of the radio altimeter AMM 34-42-00-740-002.
  • If the BITE test is not possible, refer to Para. 4. B. of this trouble shooting procedure.
4. Fault Isolation
Subtask 34-42-00-810-050-A ** ON A/C NOT FOR ALL
A. If the circuit breaker (1SA1) is closed, and if the BITE test gives the maintenance message LRRA-1 TANCEIVER.
Subtask 34-42-00-810-050-B ** ON A/C NOT FOR ALL
A. If the circuit breaker (1SA1) is closed, and if the BITE test gives the maintenance message RA 1 (2SA1).
Subtask 34-42-00-810-051-A
B. If the circuit breaker (1SA1) is closed and if the BITE test is not possible
  • do a check for 115VAC at pin AC/8 of the RA transceiver 1.
   (1) If there is no 115VAC:
  • do a check of the wiring of the 115VAC signal from circuit breaker (1SA1) to RA transceiver 1 (2SA1) ASM 344201.
     (a) If there is no continuity:
  • repair the above wiring.
     (b) If there is continuity:
  • replace the C/B-COM NAV/RAD ALTM/1 (1SA1).
   (2) If there is 115VAC:
  • do a check of the wiring of the ground signal at RA transceiver 1 pin AC/3.
     (a) If there is no continuity:
  • repair the above wiring.
     (b) If there is continuity:
       1 do the trouble shooting procedure (Ref. TSM TASK 31-32-00-810-934) related to:
  • the output Bus signal ALTITUDE BUS 1 (2) ASM 344201
Subtask 34-42-00-810-082-A
C. If the circuit breaker (1SA1) is open:
  • close this circuit breaker.
   (1) If the circuit breaker (1SA1) trips:
     (a) If this circuit breaker stays closed:
       1 If the circuit breaker trips again:
     (b) If this circuit breaker trips again:
  • do a check for a short to ground at the wiring between the circuit breaker (1SA1) and the RA transceiver 1 (2SA1). ASM 344201.
       1 If there is a short to ground:
  • repair the above wiring.
       2 If there is no short to ground:
  • replace the C/B-COM NAV/RAD ALTM/1.
       3 Install the RA transceiver 1
AMM 34-42-33-400-001.
Subtask 34-42-00-740-051-A
D. Do the test given in Para. 3.B.
[Rev.8 from Aug 2018] 2026.04.04 04:33:07 UTC
"WTRUIB" 2025