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(WARNING)
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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

06/18/19

Message Overview:

Fault Message:

APU GEN CT OPEN/SHORT CCT FAULT

Fault Code:

2420122LPS

Associated CAS:

APU GEN FAIL
(Advisory)

Reporting LRU: Auxiliary Power Unit (APU) Generator Control Unit (GCU)
System Description: 24-22-00
Schematic Diagram: 24-22-00 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 24-22-01 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Fault Description:

Auxiliary Power Unit (APU) Generator Control Unit (GCU) detects an open or short circuit condition related to the Generator Current Transformer (CT).

Possible Causes:

  • Auxiliary Power Unit (APU) Generator Control Unit (GCU) (A109)
  • Auxiliary Power Unit (APU) Generator (A110)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

A GCU patch cable (GSE REF # 24X-24-02) can be used to swap GCUs 1, 4 and 5 into position 2 or 3 (for troubleshooting only).

The GCU NVMs can only be downloaded at position #2 or #3.

Quick Links:

Removal of the APU Generator AMM 24-22-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the APU Generator AMM 24-22-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Generator Control Units (GCU) AMM 24-24-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Generator Control Units (GCU) AMM 24-24-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Swap APU GCU with GCU #2 (physically or using the GCU patch cable).
    NOTE: Use PMAT to monitor the fault on GCU.

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

  2. Disconnect connector A110P1 on the APU GEN and A109P2 on the APU GCU.
  3. Perform wiring checks (open circuit = failure) between A110P1 and A109P2 as follow:

    From To Result
    A110P1-F A109P2-41
    A110P1-E A109P2-42
    A110P1-J A109P2-50
    A110P1-D A109P2-40

    1. If wiring checks are not good, repair defective wiring as required and do close out.
    2. If wiring checks are good, continue with next step.

  4. Perform wiring checks (closed circuit = failure) between A110P1 and ground as follow:

    From To Result
    A110P1-F Ground
    A110P1-E Ground
    A110P1-J Ground
    A110P1-D Ground

    1. If wiring checks are not good, repair defective wiring as required and do close out.
    2. If wiring checks are good, continue with next step.

  5. Replace APU GEN.
  6. Do close out.

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