Failure of the Control of the Thrust-Reverser HCU Directional-Valve through the two Channels on Engine 1

TASK 78-31-00-810-815-A
Failure of the Control of the Thrust-Reverser HCU Directional-Valve through the two Channels on Engine 1

1. Possible Causes

RELAY-THRUST REV INHIBITION, ENG 1 [14KS1]
EIU-1 [1KS1]
CTL UNIT-THROTTLE, ENG 1 [8KS1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 78-31-00-810-817-A	Failure of the Control of the Thrust-Reverser HCU Directional-Valve through the Channel A on Engine 1
TSM TASK 78-31-00-810-818-A	Failure of the Control of the Thrust-Reverser HCU Directional-Valve through the Channel B on Engine 1
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)
ASM 732516
AMM 73-25-34-000-040	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-040	Installation of the Engine Interface Unit (EIU)
AMM 76-11-19-000-040	Removal of the Throttle Control Unit
AMM 76-11-19-000-042	Removal of the Throttle Control Unit
AMM 76-11-19-400-040	Installation of the Throttle Control Unit
AMM 76-11-19-400-042	Installation of the Throttle Control Unit
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

3. Fault Confirmation
Subtask 78-31-00-710-078-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the operational test of the thrust reverser system AMM 78-31-00-710-040.

Subtask 78-31-00-710-078-B ** ON A/C NOT FOR ALL

A. Test
(1) Do the operational test of the thrust reverser system AMM 78-31-00-710-042.

4. Fault Isolation
Subtask 78-31-00-810-064-E ** ON A/C NOT FOR ALL

A. The fault message is generated when the ECU detects an open circuit or a short to ground on both solenoids of the HCU directional valve on channel A and channel B or on associated electrical wiring. Most probable cause is an inhibition relay (14KS1) failure or of its control.

CAUTION: MAKE SURE THAT THERE IS NO HYDRAULIC PRESSURE WHILE YOU DO THIS TEST. PUT A WARNING NOTICE IN THE COCKPIT TO TELL PERSONS NOT TO PRESSURIZE THE HYDRAULIC SYSTEMS.

(1) If the test gives the maintenance message DIR VLV, J5, ECU then DIR VLV, J6, ECU:

remove the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) from its base on 187VU,
on the overhead panel 50VU, push and release the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend comes on,
set the engine 1 throttle lever to the reverse thrust position,
do a check for 28VDC at pin A/X of the relay base.

(a) If there is 28VDC:

make sure that ground is present at pin A/Z of the relay base.

1 If there is no ground:

repair the wiring ASM 732516.

2 If there is ground:

replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] ASM 732516.

3 If the fault continues:

do the trouble shooting for each maintenance message DIR VLV, J5, ECU (Ref. TSM TASK 78-31-00-810-817) then DIR VLV, J6, ECU (Ref. TSM TASK 78-31-00-810-818).

(b) If there is no 28VDC:

set the throttle levers to forward idle position,
on the overhead panel 50VU, push the P/BSW-ENG/FADEC GND PWR/1 (7KS1) the ON legend goes off,
remove the EIU1 (1KS1) AMM 73-25-34-000-040,
do a continuity and an insulation check of the wiring between pin A/X of the relay base 14KS1 and pin AB/10A of the EIU1 (1KS1) ASM 732516.

1 If there is an open circuit or a short to ground:

repair the wiring.

2 If nothing is found :

do a continuity check (insulation check not required) of the wiring ASM 732516 between:
. the EIU1 (1KS1) pin AA/4C and the TCU1 (8KS1) pin E/C
. the EIU1 (1KS1) pin AA/4A and the TCU1 (8KS1) pin E/C.

a If there is an open circuit:

repair the associated wiring.

b If nothing is found:

replace the EIU-1 [1KS1] AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

c If the fault continues:

replace the CTL UNIT-THROTTLE, ENG 1 [8KS1] AMM 76-11-19-000-042 and AMM 76-11-19-400-042.

(2) If the test does not give the maintenance message DIR VLV, J5, ECU then DIR VLV, J6, ECU:

replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) ASM 732516.

(a) If the fault continues:

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

(b) If the fault continues:

replace the EIU-1 (1KS1) AMM 73-25-34-000-040 and AMM 73-25-34-400-040.

replace the CTL UNIT-THROTTLE, ENG 1 (8KS1) AMM 76-11-19-000-042 and AMM 76-11-19-400-042.

Subtask 78-31-00-810-064-F ** ON A/C NOT FOR ALL