W DOC AIRBUS | TSM A320F

Failure of the Control of the Thrust-Reverser HCU Directional-Valve through the Channel A on Engine 1

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

1. Possible Causes
  • HCU-THRUST REV (4101KS)
  • RELAY-THRUST REV INHIBITION, ENG 1 [14KS1]
  • ECU [4000KS]
  • thrust reverser harness
  • aircraft wiring
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 71-51-43-000-049
Removal of the ECU (Channel A) to Thrust Reverser Junction Box Harnesses
AMM 71-51-43-400-049
Installation of the ECU (Channel A) to Thrust Reverser Junction Box Harnesses
AMM 71-51-44-000-002
Removal of the Thrust Reverser Harness 238W0908
AMM 71-51-44-400-002
Installation of the Thrust Reverser Harness 238W0908
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 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 78-31-42-210-040
Detailed Visual Inspection of the Electrical Harness
AMM 78-31-42-210-041
Detailed Visual Inspection of the electrical Harness
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 78-31-00-710-082-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do the operational test of the thrust reverser system (1A) AMM 78-31-00-710-040.
Subtask 78-31-00-710-082-B ** ON A/C NOT FOR ALL
A. Test
   (1) Do the operational test of the thrust reverser system (1A) AMM 78-31-00-710-042.
NOTE: The maintenance message HCU (TRDV), J5, ECU may be recorded in the Post Flight Report (PFR) after a ground run and associated to ECAM warning ENG X REVERSER FAULT shown at engine shut down (with master lever in OFF position).
If the ECU PN 1820M36P07 or 1820M89P07 is installed on the engine, the message is spurious. Only in this case, no trouble shooting action is required.
The following trouble shooting procedure must be carried out if the failure was detected in any other condition than above described.
4. Fault Isolation
Subtask 78-31-00-810-066-B ** 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 the solenoid of the HCU directional valve on channel A or on associated electrical wiring.
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 HCU (TRDV), J5, ECU:
  • disconnect the harness from the connector A of the HCU and apply 28VDC between pin A/4 (+) and pin A/5 (-) on the HCU,
  • make sure that the value of the current is between 350 and 630 mA.
     (a) If the current is out of the specified limits:
     (b) If the current is in the specified limits:
  • 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,
  • disconnect the harness J5 from the ECU then install a jumper wire between pins A/4 and A/5 on the thrust reverser harness J5 connector to the HCU,
  • do a continuity check between pins 7 and 8 of the harness J5.
       1 If there is no continuity:
  • remove the jumper wire from the harness pins A/4 and A/5,
  • replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] ASM 732516.
         a If the fault continues:
  • do a check of the thrust reverser harness including junction box and the aircraft wiring for open circuit AMM 78-31-42-210-040.
         b If there is no continuity:
         c If nothing is found:
       2 If there is continuity:
  • remove the jumper wire from the harness pins A/4 and A/5,
  • do a resistance check at the harness J5 connector to the ECU between:
    . pins 7 and 11 (>10 megohms)
    . pins 7 and 8 (>10 megohms)
    . pin 7 and the ground (>10 megohms).
    . pin 8 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
   (2) If the test does not give the maintenance message HCU (TRDV), J5, ECU:
  • this indicates that the fault was intermittent and is no longer present,
  • do a check of the thrust reverser harness connectors at the ECU, HCU and junction box for looseness, contamination or damaged pins,
  • clean, retighten or replace harness as required AMM 78-31-42-210-040.
     (a) If nothing is found:
  • no additional action is required.
     (b) If the fault becomes repetitive and is never confirmed during the operational test of the thrust reverser:
       1 If the fault continues:
  • replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) ASM 732516.
       2 If the fault continues:
       3 If the fault continues:
Subtask 78-31-00-810-066-C ** 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 the solenoid of the HCU directional valve on channel A or on associated electrical wiring.
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 HCU (TRDV), J5, ECU:
  • disconnect the harness from the connector A of the HCU and apply 28VDC between pin B/3 (+) and pin B/2 (-) on the HCU,
  • make sure that the value of the current is between 350 and 630 mA.
     (a) If the current is out of the specified limits:
     (b) If the current is in the specified limits:
  • 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,
  • disconnect the harness J5 from the ECU then install a jumper wire between pins B/3 and B/2 on the thrust reverser harness J5 connector to the HCU,
  • do a continuity check between pins 7 and 8 of the harness J5.
       1 If there is no continuity:
  • remove the jumper wire from the harness pins B/3 and B/2,
  • replace the RELAY-THRUST REV INHIBITION, ENG 1 [14KS1] ASM 732516.
         a If the fault continues:
  • do a check of the thrust reverser harness including junction box and the aircraft wiring for open circuit AMM 78-31-42-210-041.
         b If there is no continuity:
         c If nothing is found:
       2 If there is continuity:
  • remove the jumper wire from the harness pins B/3 and B/2,
  • do a resistance check at the harness J5 connector to the ECU between:
    . pins 7 and 11 (>10 megohms)
    . pins 7 and 8 (>10 megohms)
    . pin 7 and the ground (>10 megohms).
    . pin 8 and the ground (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
   (2) If the test does not give the maintenance message HCU (TRDV), J5, ECU:
  • this indicates that the fault was intermittent and is no longer present,
  • do a check of the thrust reverser harness connectors at the ECU, HCU and junction box for looseness, contamination or damaged pins,
  • clean, retighten or replace harness as required AMM 78-31-42-210-041.
     (a) If nothing is found:
  • no additional action is required.
     (b) If the fault becomes repetitive and is never confirmed during the operational test of the thrust reverser:
       1 If the fault continues:
  • replace the RELAY-THRUST REV INHIBITION, ENG 1 (14KS1) ASM 732516.
       2 If the fault continues:
       3 If the fault continues:
Subtask 78-31-00-710-083-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.A.
   (1) No additional maintenance action is required if the fault is not confirmed.
   (2) Repeat the fault isolation procedure if the fault continues.
[Rev.8 from Aug 2018] 2026.04.04 04:37:59 UTC
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