DOC AIRBUS | TSM A320FSLT APPU LH/RH or Wiring Fault
TASK 27-81-00-810-807-A
SLT APPU LH/RH or Wiring Fault
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 27-81-00-740-051-A
Subtask 27-81-00-810-056-A
[Rev.8 from Aug 2018]
2026.04.04 04:27:47 UTC
SLT APPU LH/RH or Wiring Fault
1. Possible Causes
- SLAT/FLAP CONTR.COMP. [21CV]
- SLAT/FLAP CONTR.COMP. [22CV]
- POSITION PICK OFF UNIT [31CV]
- POSITION PICK OFF UNIT [32CV]
- aircraft wiring
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 27-51-34-000-001 | Removal of the SFCC |
| AMM 27-51-34-400-001 | Installation of the SFCC |
| AMM 27-81-00-740-002 | BITE Test of the Slat and Flap Control Computers (Slat System) |
| ASM 278106 | |
| ASM 278107 | |
| AMM 27-81-18-000-001 | Removal of the Asymmetry-Position Pick-Off Unit |
| AMM 27-81-18-400-001 | Installation of the Asymmetry-Position Pick-Off Unit |
| AMM 27-84-00-710-001 | Operational Test of the Slat System |
Subtask 27-81-00-740-051-A
A. Test.
(1) Do a BITE test with the applicable SFCC AMM 27-81-00-740-002.
(2) If a message that includes the APPU 31CV (32CV) or the SFCC is shown on the MCDU, do the fault isolation procedure.
4. Fault Isolation(1) Do a BITE test with the applicable SFCC AMM 27-81-00-740-002.
(2) If a message that includes the APPU 31CV (32CV) or the SFCC is shown on the MCDU, do the fault isolation procedure.
Subtask 27-81-00-810-056-A
A. Procedure
(1) Swap SFCC 1 with SFCC 2
AMM 27-51-34-000-001 and AMM 27-51-34-400-001.
(a) Open these circuit breakers:
(c) Wait 60 seconds for SFCC initialization.
(d) Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(e) If the fault moves to the other SFCC position:
1 Install the serviceable SFCC to its initial position.
2 Replace the SLAT/FLAP CONTR.COMP. [21CV] or SLAT/FLAP CONTR.COMP. [22CV] that shows the fault.
(f) If the fault does not move to the other SFCC position:
1 Install the SFCCs to their initial positions.
2 Do the next step.
(2) Open these circuit breakers:
Swap the electrical connectors 31CV-A and 31CV-B or 32CV-A and 32CV-B.
(b) Wait a few seconds and close the two circuit breakers again.
(c) Wait 60 seconds for SFCC initialization.
(d) Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(e) If the fault moves to the other SFCC:
1 Replace the applicable POSITION PICK OFF UNIT [31CV] or POSITION PICK OFF UNIT [32CV]
AMM 27-81-18-000-001 and AMM 27-81-18-400-001.
2 Make sure that the related electrical connectors are correctly installed.
(f) If the fault remains in the same circuit:
1 Open, safety and tag the two circuit breakers.
2 Install the electrical connectors in their initial positions.
3 Do a check and repair the aircraft wiring between the left or right APPU and the applicable SFCC
ASM 278106 and ASM 278107.
4 Remove the safety clips and the tags and close the two circuit breakers.
5 Wait 60 seconds for SFCC initialization.
6 Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(3) After the replacement or the repair of the wiring:
(1) Swap SFCC 1 with SFCC 2
AMM 27-51-34-000-001 and AMM 27-51-34-400-001.
(a) Open these circuit breakers:
- 5CV and
- 7CV.
(c) Wait 60 seconds for SFCC initialization.
(d) Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(e) If the fault moves to the other SFCC position:
1 Install the serviceable SFCC to its initial position.
2 Replace the SLAT/FLAP CONTR.COMP. [21CV] or SLAT/FLAP CONTR.COMP. [22CV] that shows the fault.
(f) If the fault does not move to the other SFCC position:
1 Install the SFCCs to their initial positions.
2 Do the next step.
(2) Open these circuit breakers:
- 5CV and
- 7CV.
Swap the electrical connectors 31CV-A and 31CV-B or 32CV-A and 32CV-B.
(b) Wait a few seconds and close the two circuit breakers again.
(c) Wait 60 seconds for SFCC initialization.
(d) Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(e) If the fault moves to the other SFCC:
1 Replace the applicable POSITION PICK OFF UNIT [31CV] or POSITION PICK OFF UNIT [32CV]
AMM 27-81-18-000-001 and AMM 27-81-18-400-001.
2 Make sure that the related electrical connectors are correctly installed.
(f) If the fault remains in the same circuit:
1 Open, safety and tag the two circuit breakers.
2 Install the electrical connectors in their initial positions.
3 Do a check and repair the aircraft wiring between the left or right APPU and the applicable SFCC
ASM 278106 and ASM 278107.
4 Remove the safety clips and the tags and close the two circuit breakers.
5 Wait 60 seconds for SFCC initialization.
6 Set the MENU MODE and access the SLT ON GROUND FAULTS and check the ground log.
(3) After the replacement or the repair of the wiring:
- Do the operational test of the slat system AMM 27-84-00-710-001.