Failure of the T/R Hydraulic Isolation Valve in the Open Position on the Engine 1

TASK 78-31-00-810-861-A
Failure of the T/R Hydraulic Isolation Valve in the Open Position on the Engine 1

1. Possible Causes

VALVE-THRUST REVERSER HYDRAULIC ISOLATION, ENG1 (50EG1)
STATIC RELAY-THRUST REVERSER LOCKING CTL, ENG1 (3EG1)
RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1)
SEC-1 [1CE1]
SEC-2 [1CE2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 78-31-00-710-040	Operational Test of the Thrust Reverser System
AMM 78-31-00-710-042	Operational Test of the Thrust Reverser System
ASM 783701
AMM 78-37-51-000-001	Removal of the Thrust Reverser Hydraulic Isolation Valve
AMM 78-37-51-000-002	Removal of the Thrust Reverser Hydraulic Isolation Valve
AMM 78-37-51-400-001	Installation of the Thrust Reverser Hydraulic Isolation Valve
AMM 78-37-51-400-002	Installation of the Thrust Reverser Hydraulic Isolation Valve

3. Fault Confirmation
Subtask 78-31-00-710-158-B ** ON A/C NOT FOR ALL

A. Test
(1) Open, safety and tag the circuit breaker 1EG1 and do the operational test of the thrust reverser system (1A and 1B) AMM 78-31-00-710-040.

Subtask 78-31-00-710-158-C ** ON A/C NOT FOR ALL

A. Test
(1) Open, safety and tag the circuit breaker 1EG1 and do the operational test of the thrust reverser system (1A and 1B) AMM 78-31-00-710-042.

4. Fault Isolation
Subtask 78-31-00-865-052-A ** ON A/C NOT FOR ALL

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	ENG1/REV/LOCK	1EG1	N44

Subtask 78-31-00-810-112-C ** ON A/C NOT FOR ALL

B. The fault message is generated if the ECU detects a pressurization of the thrust reverser HCU during the thrust reverser isolation valve monitoring test after the engine start. The message indicates that the thrust reverser isolation valve has failed in the open position or is leaking internally.
(1) If the thrust reverser blocker doors deployed during the test:

replace the VALVE-THRUST REVERSER HYDRAULIC ISOLATION, ENG1 (50EG1) AMM 78-37-51-000-001 and AMM 78-37-51-400-001.

(2) If the thrust reverser blocker doors did not deploy during the test:

look for the cause of abnormal permanent electrical supply of the thrust reverser isolation valve or undue fault annunciation as follows ASM 783701,
replace the STATIC RELAY-THRUST REVERSER LOCKING CTL, ENG1 (3EG1).

(a) If the fault continues:

replace the RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1).

(b) If the fault continues:

remove the static relay (3EG1) from its base on shelf 120VU and do a check for permanent ground at pin A/1.

1 If there is ground:

do a check for short to ground between the SEC1 (1CE1), the SEC2 (1CE2) and the static relay (3EG1).

a If the wiring is not correct:

repair as required.

b If the wiring is correct:

do the trouble shooting of the SEC1 (1CE1) and the SEC2 (1CE2) for abnormal ground at pin AB/15E on the SEC1 (1CE1) and at pin AB/15E on the SEC2 (1CE2) ASM 783701,
look for any FCDC or radio altimeter failure (in Post Flight Report (PFR)) causing SEC output malfunction (TSM chapter 27).

. If no external failure to the SECs is found:
replace successively the SEC-1 [1CE1] then the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

Subtask 78-31-00-810-112-D ** ON A/C NOT FOR ALL

NOTE: If the failure message TR ISOL VALVE, HCU was set with failure message TR PR SW, J5/J6, ECU, do the trouble shooting for failure message TR PR SW, J5/J6, ECU separately.

(1) If the thrust reverser blocker doors deployed during the test:

replace the VALVE-THRUST REVERSER HYDRAULIC ISOLATION, ENG1 (50EG1) AMM 78-37-51-000-002 and AMM 78-37-51-400-002.

(2) If the thrust reverser blocker doors did not deploy during the test:

look for the cause of abnormal permanent electrical supply of the thrust reverser isolation valve or undue fault annunciation as follows ASM 783701,
replace the STATIC RELAY-THRUST REVERSER LOCKING CTL, ENG1 (3EG1).

(a) If the fault continues:

replace the RELAY-THRUST REVERSER LOCKING POWER, ENG1 (2EG1).

(b) If the fault continues:

remove the static relay (3EG1) from its base on shelf 120VU and do a check for permanent ground at pin A/1.

1 If there is ground:

do a check for short to ground between the SEC1 (1CE1), the SEC2 (1CE2) and the static relay (3EG1).

a If the wiring is not correct:

repair as required.

b If the wiring is correct:

do the trouble shooting of the SEC1 (1CE1) and the SEC2 (1CE2) for abnormal ground at pin AB/15E on the SEC1 (1CE1) and at pin AB/15E on the SEC2 (1CE2) ASM 783701,
look for any FCDC or radio altimeter failure (in Post Flight Report (PFR)) causing SEC output malfunction (TSM chapter 27).

. If no external failure to the SECs is found:
replace successively the SEC-1 [1CE1] then the SEC-2 [1CE2] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

Subtask 78-31-00-865-054-A ** ON A/C NOT FOR ALL

C. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	ENG1/REV/LOCK	1EG1	N44

Subtask 78-31-00-710-170-A ** ON A/C NOT FOR ALL

D. Check that the warning and failure message do not duplicate at next engine start.

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