DCV Failed Deployed

TASK 78-31-00-810-983-A
DCV Failed Deployed

1. Possible Causes

HCU-T/R, ENG1 [4310EG1]
HCU-T/R, ENG2 [4310EG2]
filter element
tubes
[3010KM1]
CHECK VALVE-ENG 1 T/R CASE DRAIN [3008KM1]
[3010KM2]
CHECK VALVE-ENG 2 T/R CASE DRAIN [3008KM2]
HCU PRESS SWITCH ENG 1B [103EG1]
HCU PRESS SWITCH ENG 2B [103EG2]
[4000KS]

2. Job Set-up Information
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 29-11-35-000-802	Removal of the Green Engine-1 Thrust-Reverser Check-Valve
AMM 29-11-35-000-803	Removal of the Green Engine-1 Thrust-Reverser Case-Drain Check-Valve
AMM 29-11-35-400-802	Installation of the Green Engine-1 Thrust-Reverser Check-Valve
AMM 29-11-35-400-803	Installation of the Green Engine-1 Thrust-Reverser Case-Drain Check-Valve
AMM 29-13-35-000-802	Removal of the Yellow Engine-2 Thrust-Reverser Check-Valve
AMM 29-13-35-000-803	Removal of the Yellow Engine-2 Thrust-Reverser Case-Drain Check-Valve
AMM 29-13-35-400-802	Installation of the Yellow Engine-2 Thrust-Reverser Check-Valve
AMM 29-13-35-400-803	Installation of the Yellow Engine-2 Thrust-Reverser Case-Drain Check-Valve
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 73-21-01-000-801	Removal of the Electronic Engine Control (EEC)
AMM 73-21-01-400-801	Installation of the Electronic Engine Control (EEC)
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 78-31-02-610-801	Servicing of the TRAS Filter Module 4314KM1, 4314KM2
AMM 78-31-21-000-801	Removal of the Hydraulic Control Unit (HCU) Pressure Switch
AMM 78-31-21-400-801	Installation of the Hydraulic Control Unit (HCU) Pressure Switch
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

3. Fault Confirmation
Subtask 78-31-00-710-298-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) 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 for reoccurring maintenance message.
(2) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.

4. 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 78-31-00-810-327-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check if both transcowls are stowed and locked.
(a) If both transcowls are not stowed and locked:
1 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.
2 Do the test given in Para. 3.
(2) If both transcowls are stowed and locked or if fault persist:
(a) Check for clogged TRAS filter (4314KM).
1 Check on filter module if red button is out.
2 If red button is out, replace filter element AMM 78-31-02-610-801.
3 Do the test given in Para. 3.
(3) If filter is not clogged or the fault continues, inspect for hydraulic leakage.
(a) Get access to HCU:
1 Remove the access panel on the pylon to get access to the HCU:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)

413AL

b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)

423AL.

(b) Open the fan cowl doors AMM 71-13-00-010-802.
(c) Inspect hydraulic tubes and hoses between HCU and T piece.
1 Replace tubes as necessary AMM 78-31-50-000-801 and AMM 78-31-50-400-801.
(d) If hydraulic leakage is corrected:
1 Do the test given in Para. 3.
(4) If the fault continues:
(a) For fault on ENG 1:

Replace [3010KM1] AMM 29-11-35-000-802 and AMM 29-11-35-400-802, and
Replace CHECK VALVE-ENG 1 T/R CASE DRAIN [3008KM1] AMM 29-11-35-000-803 and AMM 29-11-35-400-803.

(b) For fault on ENG 2:

Replace [3010KM2] AMM 29-13-35-000-802 and AMM 29-13-35-400-802, and
Replace CHECK VALVE-ENG 2 T/R CASE DRAIN [3008KM2] AMM 29-13-35-000-803 and AMM 29-13-35-400-803.

(c) Do the test given in Para. 3.
(5) If the fault continues:
(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.
(6) If no problem is found or fault continues:
(a) Replace HCU PRESS SWITCH ENG 1B [103EG1] or HCU PRESS SWITCH ENG 2B [103EG2] AMM 78-31-21-000-801 and AMM 78-31-21-400-801.
(b) Do the test given in Para. 3.
(7) If no problem found or fault continues:
(a) Replace [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 78-31-00-860-093-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.
(b) Close the pylon access panel:
1 FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)

413AL

2 FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)

423AL.

[Rev.8 from Aug 2018] 2026.04.04 04:38:18 UTC