Left TLV Failed Open

TASK 78-31-00-810-986-A
Left TLV Failed Open

1. Possible Causes

RELAY-THRUST REVERSER LOCKING POWER (2EG)
LH TRAS LOCK VALVE [4141KS]

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 78-31-00-710-805	Operational Test of Thrust Reverser with MCDU
AWM 783601
AWM 783602
AMM 78-37-02-000-801	Removal of the TRAS Track Lock Valve
AMM 78-37-02-400-801	Installation of the TRAS Track Lock Valve

3. Fault Confirmation
Subtask 78-31-00-865-058-A ** ON A/C NOT FOR ALL

A. Table of the circuit breakers referred to in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
121VU	ENG1/REV/LOCK	1EG1	N44
FOR FIN: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
121VU	ENG2/REV/LOCK	1EG2	N45

Subtask 78-31-00-710-301-A ** ON A/C NOT FOR ALL

B. 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 78-31-00-810-330-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Check if same fault comes on also on right side:
(a) If yes:
1 Open, safety and tag the circuit breaker 1EG1 for fault on ENG 1 or 1EG2 for fault on ENG 2.
2 Replace RELAY-THRUST REVERSER LOCKING POWER (2EG);
a For fault on ENG 1, refer to AWM 783601.
b For fault on ENG 2, refer to AWM 783602.
3 Remove the safety clips and tags and close the circuit breaker 1EG1 for fault on ENG 1 or 1EG2 for fault on ENG 2.
(b) If no:
1 Replace LH TRAS LOCK VALVE [4141KS] AMM 78-37-02-000-801 and AMM 78-37-02-400-801.
2 Do the test given in Para. 3.

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