DOC AIRBUS | TSM A320FFailure of the Permission Switch on Engine 1
1. Possible Causes
· RELAY-THRUST REV INHIBITION, ENG 1 ( 14KS1 )
· wiring from the EEC (4000KS) to the thrust reverser HCU1 (4101KS1)
· wiring from the EEC (4000KS) to the thrust reverser inhibition relay 1 (14KS1)
· wiring from the thrust reverser inhibition relay 1 (14KS1) to the thrust reverser HCU1 (4101KS1)
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. AMM 24-41-00-861-002 Energize the Aircraft Electrical Circuits from the External Power
Ref. AMM 24-41-00-862-002 De-energize the Aircraft Electrical Circuits Supplied from the External
Power
Ref. AMM 31-60-00-860-002 EIS Stop Procedure
Ref. AMM 71-13-00-010-010 Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 71-13-00-410-010 Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
Ref. AMM 73-22-00-710-040 Operational Test of the FADEC SYSTEM on the Ground
Ref. ASM 73-25-16
Ref. AMM 78-31-00-710-041 Operational Test of the Thrust Reverser System with the CFDS
Thrust Reverser - Engine 1 SHEET 1
Figure 78(IAE)-30-00-991-01900-A / SHEET 1/1 - Thrust Reverser - Engine 1 not printed, as per
printing preferences
3. Fault Confirmation
Subtask 78-30-00-860-136-A
A. Job Set-up
(1) Energize the aircraft electrical circuits
Ref. AMM 24-41-00-861-002 .
(2) On the panel 50VU, release the ENG/FADEC GND PWR/1 pushbutton switch.
Subtask 78-30-00-710-274-A
B. FADEC Ground Test
(1) Do the CFDS Message Decoding and read the Scheduled Maintenance Report (Ref. 70-00-00 Page
Block 301 Task Supporting Data).
(2) If the readout gives one of the following fault codes in FADEC 1A or FADEC 1B (Fault Acronym:
DCVWAF):
· do the FADEC Ground Test Ref. AMM 73-22-00-710-040 for fault confirmation.
· continue with Fault Isolation Para 4.
(3) If the fault code readout in (1) does not give one of the above listed fault codes:
· continue with fault confirmation by Engine Ground Run Section 4.B below.
Subtask 78-30-00-710-240-A
C. Test
(1) Do the operational test of the thrust reverser system with the CFDS (through FADEC 1A and 1B
menus) Ref. AMM 78-31-00-710-041 .
4. Fault Isolation
(Ref. Fig. Thrust Reverser - Engine 1 SHEET 1)
Subtask 78-30-00-810-162-A
A. If the test gives the maintenance message PERM SW/HCU/HC1:
· replace the RELAY-THRUST REV INHIBITION, ENG 1 ( 14KS1 ) .
(1) If the fault continues:
· read the fault code shown on the FLIGHT DATA and GROUND DATA of the FADEC (1A and 1B)
menu on the MCDU (Ref. 70-00-00 Page Block 301 Task Supporting Data).
· make a record of the fault code.
(2) Open the fan cowls 437AL and 438AR Ref. AMM 71-13-00-010-010 .
(3) If the FADEC 1A menu gives the fault code ACPSFL:
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser HCU1 (4101KS1)
pins J3/B, D, C to pins A/5, 2, 3
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser inhibition relay 1
(14KS1) pin J3/A to pin 2
· do a check and repair the wiring from the thrust reverser inhibition relay 1 (14KS1) to the thrust
reverser HCU1 (4101KS1) pin A to pin A/4
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser HCU1 (4101KS1)
pins J1/C, k to pins A/7, 6 Ref. ASM 73-25-16.
(4) If the FADEC 1B menu gives the fault code ACPSFL:
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser HCU1 (4101KS1)
pins J9/B, D, C to pins B/5, 2, 3
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser inhibition relay 1
(14KS1) pin J9/A to pin 4
· do a check and repair the wiring from the thrust reverser inhibition relay 1 (14KS1) to the thrust
reverser HCU1 (4101KS1) pin B to pin B/4
· do a check and repair the wiring from the EEC (4000KS) to the thrust reverser HCU1 (4101KS1)
pins J7/C, k to pins B/7, 6 Ref. ASM 73-25-16.
Subtask 78-30-00-710-275-A
B. Repeat the fault confirmation as given in Para. 3 using the same method (FADEC Ground Test or Engine
Ground Run) as before and confirm fault elimination.
5. Close-up
Subtask 78-30-00-860-137-A
A. Put the aircraft back to its initial configuration.
(1) On the ECAM control panel, set the UPPER DISPLAY and LOWER DISPLAY potentiometers to OFF.
Ref. AMM 31-60-00-860-002 .
(2) On the panel 50VU, push the ENG/FADEC GND PWR/1 pushbutton switch.
(3) De-energize the aircraft electrical circuits
Ref. AMM 24-41-00-862-002 .
(4) Make sure that the fan cowls 437AL and 438AR are closed Ref. AMM 71-13-00-410-010 . [Rev.6 from Feb 2017] 2026.04.04 04:38:07 UTC