Failure of the Hydraulic Pressurizing Valve on Engine 2

TASK 78-31-00-810-802-A
Failure of the Hydraulic Pressurizing Valve on Engine 2

1. Possible Causes

HCU-THRUST REV (4101KS)
ECU [4000KS]
PRESS SW-HCU [4102KS]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
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
AMM 78-31-16-000-040	Removal of the Hydraulic Control Unit Pressure Switch
AMM 78-31-16-000-041	Removal of the Hydraulic Control Unit Pressure Switch
AMM 78-31-16-400-040	Installation of the Hydraulic Control Unit Pressure Switch
AMM 78-31-16-400-041	Installation of the Hydraulic Control Unit Pressure Switch
AMM 78-31-51-000-040	Removal of the Hydraulic Control Unit
AMM 78-31-51-000-042	Removal of the Hydraulic Control Unit
AMM 78-31-51-400-040	Installation of the Hydraulic Control Unit
AMM 78-31-51-400-042	Installation of the Hydraulic Control Unit

3. Fault Confirmation
Subtask 78-31-00-710-052-A ** ON A/C NOT FOR ALL

A. Test
(1) Make sure that the thrust reverser system is not mechanically deactivated (Inhibition pin on HCU).
(2) Do the operational test of the thrust reverser system (2A) (MENU mode test) AMM 78-31-00-710-040. Make sure that the hydraulic pressure is correct during the test. The pressure must not drop below the advisory threshold.

NOTE: If the test gives the maintenance message HCU (TRPV), HYD, do the test again with a hydraulic ground cart or do the operational test of the thrust reverser without CFDS with engine running AMM 78-31-00-710-040.
If you do the test with an engine ground run, enter a new flight number in the FMGC menu via the MCDU keypad to get a Post Flight Report (PFR) after the test.
If warning ENG 2 REVERSER FAULT and maintenance message HCU (TRPV), HYD are shown during the test, do the following trouble shooting. If they are not shown during the test or are not recorded in the Post Flight Report (PFR) after the ground run, no further action is required.

Subtask 78-31-00-710-052-C ** ON A/C NOT FOR ALL

A. Test
(1) Make sure that the thrust reverser system is not mechanically deactivated (Inhibition pin on HCU).
(2) Do the operational test of the thrust reverser system (2A) (MENU mode test) AMM 78-31-00-710-042. Make sure that the hydraulic pressure is correct during the test. The pressure must not drop below the advisory threshold.

Subtask 78-31-00-710-052-D ** ON A/C NOT FOR ALL

A. Test
(1) Make sure that the thrust reverser system is not mechanically deactivated (Inhibition pin on HCU).
(2) Do the operational test of the thrust reverser without CFDS with engine running AMM 78-31-00-710-040.

NOTE: Enter a new flight number in the FMGC menu via the MCDU keypad to get a Post Flight Report (PFR) after the test. If warning ENG 1 REVERSER FAULT and maintenance message HCU (TRPV), HYD are shown during the test, do the following trouble shooting. If they are not shown during the test or are not recorded in the Post Flight Report (PFR) after the ground run, no further action is required.

4. Fault Isolation
Subtask 78-31-00-810-118-A ** ON A/C NOT FOR ALL

A. The fault message is generated if a position fault is detected on the HCU pressurizing valve (valve detected not open when reverse is commanded). The HCU pressurizing valve position monitoring is based upon the output signal of the HCU pressure switch (4102KS):

if the switch is closed, there is no pressure,
if the switch is open, the valve is pressurized.

(1) If the test does not give the maintenance message HCU (TRPV), HYD and the thrust reverser blocker doors deploy and stow normally:

no further action is required.

(a) If the fault becomes repetitive:

do the trouble shooting as if the maintenance message was confirmed on test.

(2) If the test does not give the maintenance message HCU (TRPV), HYD and the blocker doors do not deploy or stow normally:

replace the HCU-THRUST REV (4101KS) AMM 78-31-51-000-040 and AMM 78-31-51-400-040.

(a) If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

(3) If the test gives the maintenance message HCU (TRPV), HYD and the thrust reverser blocker doors deploy and stow normally:

replace the PRESS SW-HCU [4102KS] AMM 78-31-16-000-040 and AMM 78-31-16-400-040.

(4) If the test gives the maintenance message HCU (TRPV), HYD and the blocker doors do not deploy or stow normally:

replace the HCU-THRUST REV (4101KS) AMM 78-31-51-000-040 and AMM 78-31-51-400-040.

(a) If the fault continues:

replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

Subtask 78-31-00-810-118-B ** ON A/C NOT FOR ALL

if the switch is closed, there is no pressure,
if the switch is open, the valve is pressurized.

(1) If the test does not give the maintenance message HCU (TRPV), HYD and the thrust reverser blocker doors deploy and stow normally:

no further action is required.

(a) If the fault becomes repetitive:

do the trouble shooting as if the maintenance message was confirmed on test.

(2) If the test does not give the maintenance message HCU (TRPV), HYD and the blocker doors do not deploy or stow normally:

replace the HCU-THRUST REV (4101KS) AMM 78-31-51-000-042 and AMM 78-31-51-400-042.

(a) If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

(3) If the test gives the maintenance message HCU (TRPV), HYD and the thrust reverser blocker doors deploy and stow normally:

replace the PRESS SW-HCU [4102KS] AMM 78-31-16-000-041 and AMM 78-31-16-400-041.

(4) If the test gives the maintenance message HCU (TRPV), HYD and the blocker doors do not deploy or stow normally:

replace the HCU-THRUST REV (4101KS) AMM 78-31-51-000-042 and AMM 78-31-51-400-042.

(a) If the fault continues:

replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

Subtask 78-31-00-710-053-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:37:58 UTC