DOC AIRBUS | TSM A320FInadvertent Stow
TASK 78-31-00-810-993-A
Inadvertent Stow
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 78-31-00-710-310-A ** ON A/C NOT FOR ALL
Subtask 78-31-00-860-101-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:38:19 UTC
Inadvertent Stow
1. Possible Causes
- HCU-T/R, ENG1 [4310EG1]
- HCU-T/R, ENG2 [4310EG2]
- R UPPER ACTUATOR [3042KM1]
- LEFT UPPER ACTUATOR [3043KM2]
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 71-00-00-810-843-A | Nacelle Component and Harness Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults |
| AMM 71-13-00-010-802 | Opening of the Fan Cowl Doors |
| AMM 71-13-00-410-802 | Closing of the Fan Cowl Doors |
| AMM 78-31-00-710-805 | Operational Test of Thrust Reverser with MCDU |
| AMM 78-31-01-000-801 | Removal of the TRAS Hydraulic Control Unit (HCU) |
| AMM 78-31-01-400-801 | Installation of the TRAS Hydraulic Control Unit (HCU) |
| AMM 78-31-04-000-801 | Removal of the TRAS Locking-Feedback Actuator |
| AMM 78-31-04-400-801 | Installation of the TRAS Locking-Feedback Actuator |
| AMM 78-31-50-000-801 | Removal of the TRAS Hydraulic Tubes and Hoses |
| AMM 78-31-50-400-801 | Installation of the TRAS Hydraulic Tubes and Hoses |
| AMM 78-31-51-000-803 | Removal of the Pylon Hydraulic Tubes and Hoses |
| AMM 78-31-51-400-803 | Installation of the Pylon Hydraulic Tubes and Hoses |
Subtask 78-31-00-710-310-A ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser with the MCDU to confirm this fault AMM 78-31-00-710-805.
(1) With the thrust reverser control lever in reverse idle position, visually check if both transcowl go and stay in deployed position.
(2) If the maintenance message does not come back, troubleshoot as described in the nacelle component and harness troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-843).
(a) Monitor the engine reoccurring maintenance message.
(3) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
4. Fault Isolation(1) With the thrust reverser control lever in reverse idle position, visually check if both transcowl go and stay in deployed position.
(2) If the maintenance message does not come back, troubleshoot as described in the nacelle component and harness troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-843).
(a) Monitor the engine reoccurring maintenance message.
(3) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.
Subtask 78-31-00-810-337-A ** ON A/C NOT FOR ALL A. If there is confirmation of the fault:
(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) If both transcowls do not go to deploy position or come back to stowed position when the thrust reverser control lever is in reverse idle position, check for other fault messages regarding DCV 28V NOT AVAIL or DCV SOL FAIL.
(a) If any of these messages comes on, troubleshoot them first.
1 Do the test given in Para. 3.
(b) If no messages comes on or if fault continues, inspect the hydraulic deploy lines between the Hydraulic Control Unit (HCU) and T-pieces for hydraulic leakage.
1 If any damage is found:
a Repair or replace the hydraulic lines AMM 78-31-51-000-803 and AMM 78-31-51-400-803.
b Do the test given in Para. 3.
2 If no damage is found:
a Replace HCU-T/R, ENG1 [4310EG1] or HCU-T/R, ENG2 [4310EG2] AMM 78-31-01-000-801 and AMM 78-31-01-400-801.
b Do the test given in Para. 3.
(3) If only one transcowl goes to deploy position or comes back to stowed position when the thrust reverser control lever is in reverse idle position, inspect the hydraulic deploy lines between T-pieces and lock feedback actuator for hydraulic leakage.
(a) Repair or replace the hydraulic deploy line as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
(b) Do the test given in Para. 3.
(4) If both transcowls go and stay at deployed position when the thrust reverser control lever is in reverse idle position, check for the correct engagement of connectors (4003KS-A) and (4004KS-A).
(a) If engagement is not correct, correct as necessary.
(b) If engagement is correct:
1 Replace R UPPER ACTUATOR [3042KM1] and LEFT UPPER ACTUATOR [3043KM2] AMM 78-31-04-000-801 and AMM 78-31-04-400-801.
2 Do the test given in Para. 3.
5. Close-up(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) If both transcowls do not go to deploy position or come back to stowed position when the thrust reverser control lever is in reverse idle position, check for other fault messages regarding DCV 28V NOT AVAIL or DCV SOL FAIL.
(a) If any of these messages comes on, troubleshoot them first.
1 Do the test given in Para. 3.
(b) If no messages comes on or if fault continues, inspect the hydraulic deploy lines between the Hydraulic Control Unit (HCU) and T-pieces for hydraulic leakage.
1 If any damage is found:
a Repair or replace the hydraulic lines AMM 78-31-51-000-803 and AMM 78-31-51-400-803.
b Do the test given in Para. 3.
2 If no damage is found:
a Replace HCU-T/R, ENG1 [4310EG1] or HCU-T/R, ENG2 [4310EG2] AMM 78-31-01-000-801 and AMM 78-31-01-400-801.
b Do the test given in Para. 3.
(3) If only one transcowl goes to deploy position or comes back to stowed position when the thrust reverser control lever is in reverse idle position, inspect the hydraulic deploy lines between T-pieces and lock feedback actuator for hydraulic leakage.
(a) Repair or replace the hydraulic deploy line as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
(b) Do the test given in Para. 3.
(4) If both transcowls go and stay at deployed position when the thrust reverser control lever is in reverse idle position, check for the correct engagement of connectors (4003KS-A) and (4004KS-A).
(a) If engagement is not correct, correct as necessary.
(b) If engagement is correct:
1 Replace R UPPER ACTUATOR [3042KM1] and LEFT UPPER ACTUATOR [3043KM2] AMM 78-31-04-000-801 and AMM 78-31-04-400-801.
2 Do the test given in Para. 3.
Subtask 78-31-00-860-101-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the fan cowl doors AMM 71-13-00-410-802.