W DOC AIRBUS | TSM A320F

Thrust-Reverser Blocker-Door Stow-Switches Feedback Disagree on Engine 1

TASK 78-31-00-810-839-A
Thrust-Reverser Blocker-Door Stow-Switches Feedback Disagree on Engine 1

1. Possible Causes
  • SW-BLOCKER DOOR STOW, UPPER R [4104KS1]
  • SW-BLOCKER DOOR STOW, LOWER R [4104KS2]
  • SW-BLOCKER DOOR STOW, LOWER L [4104KS3]
  • SW-BLOCKER DOOR STOW, UPPER L [4104KS4]
  • left electrical harness
  • right electrical harness
  • electrical junction box
  • ECU [4000KS]
  • HARNESS-JUNCTION BOX TO THRUST REVERSER, CHAN A/B [4200KS]
  • HARNESS-ECU TO THRUST REVERSER JUNCTION BOX CHAN A [4213KS]
  • HARNESS-ECU TO THRUST REVERSER JUNCTION BOX, CHAN B [4214KS]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AWM 715105
AMM 71-51-43-000-004
Removal of the ECU (Channel B) to Thrust Reverser Junction Box Harnesses
AMM 71-51-43-000-044
Removal of the Thrust Reverser (Channel A and B) Harness
AMM 71-51-43-000-049
Removal of the ECU (Channel A) to Thrust Reverser Junction Box Harnesses
AMM 71-51-43-400-004
Installation of the ECU (Channel B) to thrust Reverser Junction Box Harnesses
AMM 71-51-43-400-044
Installation of the Thrust Reverser (Channel A and B) Harness
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 71-51-44-000-004
Removal of the Electronic Control Unit (ECU) Channel A Harness 238W0904
AMM 71-51-44-000-005
Removal of the Electronic Control Unit (ECU) Channel B Harness 238W0904
AMM 71-51-44-400-002
Installation of the Thrust Reverser Harness 238W0908
AMM 71-51-44-400-004
Installation of the Electronic Control Unit (ECU) Channel A Harness 238W0904
AMM 71-51-44-400-005
Installation of the Electronic Control Unit (ECU) Channel B Harness 238W0904
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 78-31-18-000-001
Removal of the Blocker Door Stow-switch
AMM 78-31-18-000-040
Removal Blocker Door Stow-switch
AMM 78-31-18-400-001
Installation of the Blocker Door Stow-switch
AMM 78-31-18-400-040
Installation Blocker Door Stow-switch
AMM 78-31-42-000-040
Removal of the Left Electrical Harness
AMM 78-31-42-000-041
Removal of the Right Electrical Harness
AMM 78-31-42-000-043
Removal of the Left Electrical Harness
AMM 78-31-42-000-044
Removal of the Right Electrical Harness
AMM 78-31-42-000-802
Removal of the Electrical Junction Box
AMM 78-31-42-000-803
Removal of the Electrical Junction Box
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 78-31-42-400-040
Installation of the Left Electrical Harness
AMM 78-31-42-400-041
Installation of the Right Electrical Harness
AMM 78-31-42-400-043
Installation of the Left Electrical Harness
AMM 78-31-42-400-044
Installation of the Right Electrical Harness
AMM 78-31-42-400-802
Installation of the Electrical Junction Box
AMM 78-31-42-400-803
Installation of the Electrical Junction Box
AMM 78-32-41-860-001
Manual Deployment of the Blocker Door
AMM 78-32-41-860-002
Manual Stowing of the Blocker Door
AMM 78-32-41-860-040
Manual Deployment of the Blocker Door
AMM 78-32-41-860-041
Manual Stowing of the Blocker Door
3. Fault Confirmation
Subtask 78-31-00-710-124-A ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser system (1A and 1B) AMM 78-31-00-710-040.
Subtask 78-31-00-710-124-B ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser system (1A and 1B) AMM 78-31-00-710-042.
Subtask 78-31-00-710-124-C ** ON A/C NOT FOR ALL
A. Do the operational test of the thrust reverser system (1A and 1B) AMM 78-31-00-710-040.
4. Fault Isolation
Subtask 78-31-00-810-088-A ** ON A/C NOT FOR ALL
A. This fault message is generated if there is a disagreement between channel A and channel B on the stow switch signal of the thrust reverser blocker doors. Most probable cause is stow switches or a harness failure.
NOTE: Some stow switches have quality defects. Service Bulletin RA32078-68 gives the list of these stow switches and also the instructions to examine and replace the unsatisfactory stow switches on the thrust reverser.
   (1) If the test gives the maintenance message STOW SW, J5/J6, ECU on the channel A or B:
  • Make sure that the thrust reverser blocker doors are in the stowed position.
  • Disconnect the harnesses J5 and J6 from the ECU (4000KS).
  • Do a resistance check of the harnesses J5 and J6 AWM 715105 between:
    . Pins 24 and 23 (<5 ohms)
    . Pins 24 and 2 (>10 megohms)
    . Pins 24 and 11 (>10 megohms)
    . Pins 2 and 11 (>10 megohms)
    . Pin 24 and the ground (>10 megohms)
    . Pin 23 and the ground (>10 megohms).
     (a) If the resistance values are out of the specified limits:
  • With the thrust reverser blocker doors in the stowed position, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch AWM 715105 between:
    . pins 4 and 7 (>10 megohms)
    . pins 4 and 9 (<5 ohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (>10 megohms)
    . Pins 2 and 5 (<5 ohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
       1 If the resistance values are out of the specified limits:
       2 If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS) AWM 715105.
  • Do a visual check of each connector for correct condition.
         a If damage is found:
  • Repair or replace as required.
         b If nothing is found:
         c If the fault continues:
         d If the fault continues:
         e If the fault continues:
         f If the fault continues:
     (b) If the resistance values are in the specified limits:
  • Do a manual deployment of the thrust reverser blocker doors AMM 78-32-41-860-040.
  • Do a resistance check of the harnesses J5 and J6 AWM 715105 between:
    . Pins 24 and 23 (>10 megohms)
    . Pins 24 and 2 (<5 ohms)
    . Pins 24 and 11 (>10 megohms)
    . Pins 2 and 11 (>10 megohms)
    . Pin 24 and the ground (>10 megohms)
    . Pin 23 and the ground (>10 megohms).
       1 If the resistance values are out of the specified limits:
  • Do a manual stowing of the thrust reverser blocker doors AMM 78-32-41-860-041.
  • With the thrust reverser blocker doors in the stowed position, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch between:
    . Pins 4 and 7 (>10 megohms)
    . Pins 4 and 9 (<5 ohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (>10 megohms)
    . Pins 2 and 5 (<5 ohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS).
  • Do a visual check of each connector for correct condition.
         c If damage is found:
  • Repair or replace as required.
         d If nothing is found:
         e If the fault continues:
         f If the fault continues:
         g If the fault continues:
         h If the fault continues:
       2 If the resistance values are in the specified limits:
  • Do a manual deployment of the thrust reverser blocker doors AMM 78-32-41-860-040.
  • with the thrust reverser blocker doors deployed, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch AWM 715105 between:
    . Pins 4 and 7 (<5 ohms)
    . Pins 4 and 9 (>10 megohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (<5 ohms)
    . Pins 2 and 5 (>10 megohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS).
  • Do a visual check of each connector for correct condition.
         c If damage is found:
  • Repair or replace as required.
         d If nothing is found:
         e If the fault continues:
         f If the fault continues:
         g If the fault continues:
         h If the fault continues:
   (2) If the test does not give the maintenance message STOW SW, J5/J6, ECU:
     (a) Do a check of the connectors of the thrust reverser harness, harnesses J5 and J6 for looseness, contamination, and bent pins.
       1 If damage is found:
     (b) Do a check of the harness routing and look for chafing or cut in the harness envelope.
       1 If damage is found:
       2 If nothing is found and the fault continues while the fault message is never confirmed during the thrust reverser test:
         a If the fault continues:
         b If nothing is found:
         c If the fault continues:
Subtask 78-31-00-810-088-B ** ON A/C NOT FOR ALL
A. This fault message is generated if there is a disagreement between channel A and channel B on the stow switch signal of the thrust reverser blocker doors. Most probable cause is stow switches or a harness failure.
   (1) If the test gives the maintenance message STOW SW, J5/J6, ECU on the channel A or B:
  • Make sure that the thrust reverser blocker doors are in the stowed position.
  • Disconnect the harnesses J5 and J6 from the ECU (4000KS).
  • Do a resistance check of the harnesses J5 and J6 AWM 715105 between:
    . Pins 24 and 23 (<5 ohms)
    . Pins 24 and 2 (>10 megohms)
    . Pins 24 and 11 (>10 megohms)
    . Pins 2 and 11 (>10 megohms)
    . Pin 24 and the ground (>10 megohms)
    . Pin 23 and the ground (>10 megohms).
     (a) If the resistance values are out of the specified limits:
  • With the thrust reverser blocker doors in the stowed position, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch AWM 715105 between:
    . Pins 4 and 7 (>10 megohms)
    . Pins 4 and 9 (<5 ohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (>10 megohms)
    . Pins 2 and 5 (<5 ohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
       1 If the resistance values are out of the specified limits:
       2 If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS) AWM 715105.
  • Do a visual check of each connector for correct condition.
         a If damage is found:
  • Repair or replace as required.
         b If nothing is found:
         c If the fault continues:
         d If the fault continues:
         e If the fault continues:
         f If the fault continues:
     (b) If the resistance values are in the specified limits:
  • Do a manual deployment of the thrust reverser blocker doors AMM 78-32-41-860-001.
  • Do a resistance check of the harnesses J5 and J6 AWM 715105 between:
    . Pins 24 and 23 (>10 megohms)
    . Pins 24 and 2 (<5 ohms)
    . Pins 24 and 11 (>10 megohms)
    . Pins 2 and 11 (>10 megohms)
    . Pin 24 and the ground (>10 megohms)
    . Pin 23 and the ground (>10 megohms).
       1 If the resistance values are out of the specified limits:
  • Do a manual stowing of the thrust reverser blocker doors AMM 78-32-41-860-002.
  • With the thrust reverser blocker doors in the stowed position, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch between:
    . Pins 4 and 7 (>10 megohms)
    . Pins 4 and 9 (<5 ohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (>10 megohms)
    . Pins 2 and 5 (<5 ohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS).
  • Do a visual check of each connector for correct condition.
         c If damage is found:
  • Repair or replace as required.
         d If nothing is found:
         e If the fault continues:
         f If the fault continues:
         g If the fault continues:
         h If the fault continues:
       2 If the resistance values are in the specified limits:
  • Do a manual deployment of the thrust reverser blocker doors AMM 78-32-41-860-001.
  • With the thrust reverser blocker doors deployed, disconnect the harnesses J5 and J6 from each stow switch.
  • Do a resistance check on each stow switch AWM 715105 between:
    . Pins 4 and 7 (<5 ohms)
    . Pins 4 and 9 (>10 megohms)
    . Pin 4 and the ground (>10 megohms)
    . Pins 4 and 12 (>10 megohms)
    . Pins 2 and 3 (<5 ohms)
    . Pins 2 and 5 (>10 megohms)
    . Pin 2 and the ground (>10 megohms)
    . Pins 2 and 1 (>10 megohms).
         a If the resistance values are out of the specified limits:
         b If the resistance values are in the specified limits:
  • Do a continuity and insulation check of the thrust reverser and harnesses J5 and J6 between the stow switches including the junction box (4100KS).
  • Do a visual check of each connector for correct condition.
         c If damage is found:
  • Repair or replace as required.
         d If nothing is found:
         e If the fault continues:
         f If the fault continues:
         g If the fault continues:
         h If the fault continues:
   (2) If the test does not give the maintenance message STOW SW, J5/J6, ECU:
     (a) Do a check of the connectors of the thrust reverser harness, harnesses J5 and J6 for looseness, contamination, and bent pins.
       1 If damage is found:
     (b) Do a check of the harness routing and look for chafing or cut in the harness envelope.
       1 If damage is found:
       2 If nothing is found and the fault continues while the fault message is never confirmed during the thrust reverser test:
         a If the fault continues:
         b If nothing is found:
         c If the fault continues:
Subtask 78-31-00-710-125-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 04:38:00 UTC
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