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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

06/18/19

Message Overview:

Fault Message:

APUGCU PIN PROGRAMMING FAULT

Fault Code:

2420128LPS

Associated CAS:

APU GEN FAIL
(Advisory)

Reporting LRU: Auxiliary Power Unit (APU) Generator Control Unit (GCU)
System Description: 24-21-00
Schematic Diagram: 24-21-00 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 24-24-05 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Fault Description:

Auxiliary Power Unit (APU) Generator Control Unit (GCU), during initial power up (cold start), has detected a fault in the pin programming wiring or in the pin programming sensing circuit, consequently the Generator will not come on line.

Possible Causes:

  • Auxiliary Power Unit (APU) Generator Control Unit (GCU) (A109)
  • 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 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 APU GCU (A109P2).
  3. Perform wiring checks for open circuits as follow:

    From To Result
    A109P2-27 A109P2-43

    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 for short circuits as follow:

    From To Result
    A109P2-17 A109P2-35
    A109P2-18 A109P2-34
    A109P2-26 A109P2-44

    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. Do close out.

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