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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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Quick Links

08/13/25

Message Overview:

Message Name:

LANDING GEAR DID NOT EXTEND

Associated CAS:

PROX SYS FAULT
(Advisory)

Reporting LRU: RET VALVE; RET CM
System Description: 32-60-00 - Landing Gear System
Schematic Diagram: 32-61-00 - Position Indication System
Wiring Diagram: 32-31-01 - Landing-Gear Selector Valve
32-61-09 - Proximity-Sensor Electronic Unit (PSEU)

Message Description:

Proximity Sensor Electronic Unit detects that the discrete output to the Retract Valve has an unreasonable load connected.

Possible Causes:

  • Landing-Gear Selector Valve (V9)
  • Junction Box 4 (JB4) Circuit-Card 2 (JB4-DB2)
  • Proximity Sensor-Electronic Unit (PSEU) (A9)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

Quick Links:

Removal of the Junction Box JB4 Circuit-Cards AMM 24-63-13-000-803
Installation of the Junction Box JB4 Circuit-Cards AMM 24-63-13-400-803
Operational Test of Junction Box JB4 Card 2 AMM 24-63-13-710-802
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
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
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. Access MDC Fault Maintenance History and check if the following faults are recorded

    1. If YES, follow the troubleshooting procedure
    2. If NO, continue with next step.

  3. Do wiring check from the JB4 connector JB4AP1 Pin E14 to the PSEU connector A9CP1 Pin F10. Repair as required.

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

  4. Do wiring check from the JB4 connector JB4AP1 Pin A14 to the PSEU connector A9CP1 Pin E10. Repair as required.

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

  5. Do wiring check from the JB4 connector JB4AP1 Pin K13 to the Retract Valve connector V9P1 Pin E. Repair as required.

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

  6. Replace the Retract Valve V9.

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

  7. 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.

  8. Replace the PSEU.
  9. Do close out.

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