DOC AIRBUS | TSM A320FSLT APPU LH/RH or SFCC Interface Fault
TASK 27-81-00-810-802-A
SLT APPU LH/RH or SFCC Interface Fault
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 27-81-00-865-051-A
Subtask 27-81-00-810-051-A
Subtask 27-81-00-942-053-A
[Rev.8 from Aug 2018]
2026.04.04 04:27:46 UTC
SLT APPU LH/RH or SFCC Interface 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 27-80-00-866-004 | Extending the Slats on the Ground |
| AMM 27-80-00-866-005 | Retracting the Slats on the Ground |
| 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 27-81-00-865-051-A
A. Table of the circuit breakers used in this procedure:
Subtask 27-81-00-710-051-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 49VU | FLIGHT CONTROLS/SLT/CTL AND MONG/SYS1 | 5CV | B06 |
| 121VU | FLIGHT CONTROLS/SLT/CTL/SYS2 | 7CV | R21 |
B. Reset and Initialization
(1) At the circuit breakers:
(a) Open the circuit breakers.
(b) Wait for 3 seconds and close the circuit breakers.
(c) Wait for 60 seconds.
(2) Move the slats AMM 27-80-00-866-004 AMM 27-80-00-866-005
(a) Examine the UPPER ECAM and the SD FLT/CTL page for the fault warnings and system status.
(b) Access the SLT ON GROUND FAULTS page and do a check of the ground log.
(c) If an UPPER ECAM warning, SD FLT/CTL status and a ground log fault message are displayed, do the fault isolation.
(d) If the UPPER ECAM, SD FLT/CTL status and the SLT ON GROUND FAULTS log are clear, no further maintenance action is required.
4. Fault Isolation(1) At the circuit breakers:
(a) Open the circuit breakers.
(b) Wait for 3 seconds and close the circuit breakers.
(c) Wait for 60 seconds.
(2) Move the slats AMM 27-80-00-866-004 AMM 27-80-00-866-005
(a) Examine the UPPER ECAM and the SD FLT/CTL page for the fault warnings and system status.
(b) Access the SLT ON GROUND FAULTS page and do a check of the ground log.
(c) If an UPPER ECAM warning, SD FLT/CTL status and a ground log fault message are displayed, do the fault isolation.
(d) If the UPPER ECAM, SD FLT/CTL status and the SLT ON GROUND FAULTS log are clear, no further maintenance action is required.
Subtask 27-81-00-810-051-A
A. Procedure
(1) Set the MCDU to MENU MODE page 2 and access submenu <SLT SYSTEM DATA.
(a) Press the line key 1R <PPU.
(b) Do a check of the PPU DATA (DEG) page. Refer to page block 301 table 2 for APPU fault analysis.
(c) If the no data "xxxx.x" is shown:
(2) Swap SFCC1 and SFCC2
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] ( 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 step (3).
(3) Open, safety and tag these circuit breakers:
Swap the electrical connectors 31CV-A and 31CV-B or 32CV-A and 32CV-B.
(b) Remove the safety clips and the tags and close the two 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:
1 Replace the applicable POSITION PICK OFF UNIT [31CV] ( 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 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.
(4) After the replacement or the repair of the wiring:
5. Close-up(1) Set the MCDU to MENU MODE page 2 and access submenu <SLT SYSTEM DATA.
(a) Press the line key 1R <PPU.
(b) Do a check of the PPU DATA (DEG) page. Refer to page block 301 table 2 for APPU fault analysis.
(c) If the no data "xxxx.x" is shown:
(2) Swap SFCC1 and SFCC2
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] ( 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 step (3).
(3) Open, safety and tag these circuit breakers:
- 5CV and
- 7CV.
Swap the electrical connectors 31CV-A and 31CV-B or 32CV-A and 32CV-B.
(b) Remove the safety clips and the tags and close the two 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:
1 Replace the applicable POSITION PICK OFF UNIT [31CV] ( 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 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.
(4) After the replacement or the repair of the wiring:
- Do the operational test of the slat system AMM 27-84-00-710-001.
Subtask 27-81-00-942-053-A
A. Remove the ground support and maintenance equipment, the special and standard tools and all other items.
Subtask 27-81-00-860-053-A B. Put the aircraft back to its initial configuration.