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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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03/15/21

Message Overview:

Message Name:

LG UNCOMMANDED MVT

Message Code:

B3-007648

Associated CAS:

GEAR DISAGREE
(Caution)

Reporting LRU: PSEU LRU
System Description: 32-60-00
Schematic Diagram: 32-61-00
Wiring Diagram: 32-31-01
32-61-01
32-61-09
32-61-12
34-42-09

Message Description:

Proximity Sensor Electronic Unit detects uncommanded movement of the Left Gear. Verify PSEU, aircraft wiring, and gear sensor rigging/status.

Possible Causes:

  • Main Landing-Gear Uplock Proximity-Sensor (LH) (PX05)
  • Main Landing-Gear Downlock 1 Proximity-Sensor (LH) (PX09)
  • Main Landing-Gear Downlock 2 Proximity-Sensor (LH) (PX39)
  • TAWS/LANDING GEAR Control-Panel (PL10)
  • Junction Box 4 (JB4) Circuit Board 2
  • Landing-Gear Selector Valve (V9)
  • Proximity-Sensor Electronic Unit (PSEU) (A9)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Junction Box JB1 AMM 24-63-01-000-802
Installation of the Junction Box JB1 AMM 24-63-01-400-802
Operational Test of Junction Box JB2 Card 1 AMM 24-63-05-710-826
Operational Test of the Extension and Retraction System AMM 32-30-00-710-801
Removal of the Landing-Gear Selector Valve AMM 32-31-01-000-801
Installation of the Landing-Gear Selector Valve AMM 32-31-01-400-801
Adjustment of the Proximity Sensors AMM 32-61-00-820-801
Removal of the Main Landing-Gear (MLG) Proximity-Sensors AMM 32-61-01-000-801
Installation of the Main Landing-Gear (MLG) Proximity-Sensors AMM 32-61-01-400-801
Removal of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-000-801
Installation of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-400-801
Functional Test of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-720-801
Removal of the TAWS/LANDING GEAR Control-Panel AMM 34-42-09-000-801
Installation of the TAWS/LANDING GEAR Control-Panel AMM 34-42-09-400-801
Operational Test of the TAWS/LANDING GEAR Control-Panel AMM 34-42-09-710-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02
Electrical Connectors - Maintenance Practice - ALL SPM 20-20-00-02

Troubleshooting Recommendations:

  1. Do the rigging with the adjustment of the sensor PX09.

    1. If the rigging is good, go to step 4.
    2. If fault remains, continue with next step.

  2. Replace the sensor PX09.
  3. Go to step 1.
  4. Do the rigging with the adjustment of the sensor PX39.

    1. If the rigging is good, go to step 7.
    2. If fault remains, continue with next step.

  5. Replace the sensor PX39.
  6. Go to step 4.
  7. Do the rigging with the adjustment of the sensor PX05.

    1. If the rigging is good, go to step 10.
    2. If fault remains, continue with next step.

  8. Replace the sensor PX05.
  9. Go to step 7.
  10. Do voltage check (28 VDC) on PSEU connector A9BP1 pins: 3A, 4A, 3C, 4C, 7H, 7K, 8H, 8K. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  11. Do grounds check (< 0.5Ω) on PSEU connector A9BP1 pins: 3H, 4H, 3K, 4K, 7A, 7C, 8A, 8C. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  12. Do wiring check from the PSEU A9BP1 Pin 15B to PL10J/P1 Pin 3 (Landing Gear Control Panel PL10). Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  13. Do wiring check from the JB4 connector JB4AP1 Pin 14F to the PSEU connector A9CP1 Pin 4C. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  14. Do wiring check from the JB4 connector JB4AP1 Pin 14B to the PSEU connector A9CP1 Pin 5C. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  15. Do wiring check from the JB4 connector JB4AP1 Pin 13H to the Retract Valve connector V9P1 Pin B. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  16. Replace the Retract Valve V9.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  17. Replace the Circuit Board 2 of the JB4.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  18. Do wiring check of the ARINC 429 data bus from the PSEU A9CP1 pins 1B, 2B to IAPS A4P1 pins 61, 62, and PSEU A9CP1 pins 1B, 2B to DCU pins A14DP1 1A, 1B. Repair as required.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  19. With Aircraft Power OFF, set the Gear Control Handle to RETRACT.
  20. Do wiring check of the Landing Gear Control Panel from Pl10P/J1 Pin 17 and Pin 3. Ensure to have a good ground < 0.5Ω on PL10P/J1 Pin 17. Ensure there is no continuity between Pl10P/J1 Pin 17 and Pin 4. Ensure there is no continuity between Pl10P/J1 Pin 1 and Pin 2. Ensure there is continuity between Pl10P/J1 Pin 5 and Pin 6.

    1. If system checks are good, do close out.
    2. If fault remains, go to step 23.

  21. Set the Gear Control Handle to EXTEND.
  22. Do wiring check of the Landing Gear Control Panel from Pl10P/J1 Pin 17 and Pin 4. Ensure to have a good ground < 0.5Ω on PL10P/J1 Pin 17. Ensure there is no continuity between Pl10P/J1 Pin 17 and Pin 3. Ensure there is continuity between Pl10P/J1 Pin 1 and Pin 2. Ensure there no is continuity between Pl10P/J1 Pin 5 and Pin 6.

    1. If system checks are good, go to step 24.
    2. If fault remains, continue with next step.

  23. Replace the TAWS/ LANDING GEAR Control Panel.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

  24. Replace the PSEU.
  25. Do the functional test the PSEU.

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