Stow Time Too Long on Engine 2 Thrust Reverser

TASK 78-31-00-810-848-A
Stow Time Too Long on Engine 2 Thrust Reverser

1. Possible Causes

shut-off valve filter
HCU filter
CHECK VALVE-ENG 2 THR REV, Y
HCU return line
HCU-THRUST REV (4101KS)
ECU [4000KS]
ACTUATOR-BLOCKER DOOR, UPPER R [3001KM1]
ACTUATOR-BLOCKER DOOR, LOWER R [3001KM2]
ACTUATOR-BLOCKER DOOR, LOWER L [3001KM3]
ACTUATOR-BLOCKER DOOR, UPPER L [3001KM4]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 29-11-35-000-001	Removal of the Engine 1 Thrust Reverser Check Valve
AMM 29-11-35-400-001	Installation of the Engine 1 Thrust Reverser Check Valve
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 78-31-41-000-001	Removal of the Blocker Door Hydraulic Actuator
AMM 78-31-41-000-040	Removal of the Blocker Door Hydraulic Actuators
AMM 78-31-41-210-003	Detailed Visual Inspection of the Door Actuator
AMM 78-31-41-210-040	Detailed Visual Inspection of the Blocker Door Actuator
AMM 78-31-41-400-001	Installation of the Blocker Door Hydraulic Actuator
AMM 78-31-41-400-040	Installation of the Blocker Door Hydraulic Actuators
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
AMM 78-31-51-920-001	Replacement of the Hydraulic Control Unit Filter
AMM 78-31-51-920-040	Replacement of the Hydraulic Control Unit Filter
AMM 78-32-41-860-001	Manual Deployment of the Blocker Door
AMM 78-37-51-600-001	Replacement of the Thrust Reverser Hydraulic Isolation Valve Filter
AMM 78-37-51-600-002	Replacement of the Thrust Reverser Hydraulic Isolation Valve Filter

3. Fault Confirmation
Subtask 78-31-00-710-142-A ** ON A/C NOT FOR ALL

A. Test

CAUTION: STAY AWAY FROM THE TRAVEL RANGE OF THE BLOCKER DOORS DURING THE TEST.

(1) Do an operational test of the thrust reverser system for the FADEC 2A AMM 78-31-00-710-042. Visually monitor the blocker doors operation during the test.

Subtask 78-31-00-710-142-B ** ON A/C NOT FOR ALL

A. Test

CAUTION: STAY AWAY FROM THE TRAVEL RANGE OF THE BLOCKER DOORS DURING THE TEST.

(1) Do an operational test of the thrust reverser system for the FADEC 2A AMM 78-31-00-710-040. Visually monitor the blocker doors operation during the test.

4. Fault Isolation
Subtask 78-31-00-810-098-B ** ON A/C NOT FOR ALL

A. The fault message HCU is generated if the thrust reverser stow time is greater than 8 seconds between the setting of the throttle from reverse to forward idle and the locking of the reverser blocker doors.
(1) If all blocker doors stow simultaneously but slowly during the test:

do a check of the filter clogging pop out indicator of the reverser shut-off valve filter.

(a) If the clogging pop out indicator is extended:

replace the shut-off valve filter AMM 78-37-51-600-002.

(b) If the clogging pop out indicator is not extended:

do a check of the HCU filter clogging pop out indicator.

1 If the HCU filter clogging pop out indicator is extended:

replace the HCU filter AMM 78-31-51-920-001.

2 If the clogging pop out indicator is not extended:

remove the hydraulic return line between the HCU and the check valve (3010KM2) at the pylon connection,
do an inspection for blockage or damage.

a If there is blockage or damage:

clean or replace the CHECK VALVE-ENG 2 THR REV, Y AMM 29-11-35-000-001 and AMM 29-11-35-400-001 or HCU return line .

b If nothing is found:

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

c If the fault continues and slow reverser operation in the stow sequence does not exceed 8 seconds during the test:

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

(2) If the blocker doors do not stow simultaneously during the test:

do a manual deployment of the thrust reverser blocker doors AMM 78-32-41-860-001,
with the blocker doors in the deployed position, do a visual inspection of the structure and hydraulic lines AMM 78-31-41-210-003.

(a) If you find damage:

replace the damaged parts.

(b) If nothing is found and if one or more of the doors is (are) identified to move slower than the other ones during the test:

replace the defective:
. ACTUATOR-BLOCKER DOOR, UPPER R [3001KM1] or/and
. ACTUATOR-BLOCKER DOOR, LOWER R [3001KM2] or/and
. ACTUATOR-BLOCKER DOOR, LOWER L [3001KM3] or/and
. ACTUATOR-BLOCKER DOOR, UPPER L [3001KM4] AMM 78-31-41-000-001 and AMM 78-31-41-400-001.

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

Subtask 78-31-00-810-098-F ** ON A/C NOT FOR ALL

do a check of the filter clogging pop out indicator of the reverser shut-off valve filter.