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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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06/18/19

Message Overview:

Fault Message:

APU GEN FIRE TRIP

Fault Code:

2420120LPS

Associated CAS:

APU GEN FAIL
(Advisory)

Reporting LRU: Auxiliary Power Unit (APU) Generator
System Description: 24-22-00
26-21-00
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 has been tripped off-line and CAS message APU GEN FAIL posted due to deliberate operation of the APU fire handle
  • Auxiliary Power Unit (APU) Generator has tripped off-line or will not come on-line and APU GEN FAIL CAS message is posted due to a fault associated

Possible Causes:

  • Auxiliary Power Unit (APU) Generator Control Unit (GCU) (A109)
  • Auxiliary Power Unit (APU) Fire Handle (A211)
  • Auxiliary Power Unit (APU) Fire Handle Switch
  • 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 GCU 1, GCU 2, GCU 3, GCU 4 and the APU GCU into a different position (for troubleshooting only). You can monitor the GCU faults in CAIMS via the active faults page.

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 ]
Operational Test of the Fire Extinguishing System AMM 26-21-00-710-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Was operation of the APU engine-fire-handle reported?

    1. If YES, investigate the reason, restore handle position and do close out.
    2. If NO, continue with next step.

  2. Swap APU GCU with GCU 2 (physically or using the GCU patch cable).
    NOTE: Using the PMAT, monitor the fault on GCU 2.

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

  3. Disconnect connector A109P2 (APU GCU) and connector A211P1 (APU fire handle).
  4. Perform a continuity check between connector A109P2 and ground as follows:

    From To Result
    A109P2-20 Ground

    1. If there is continuity, repair defective wiring as required and do close out.
    2. If there is no continuity, continue with next step.

  5. Do the operational test of the fire extinguishing system in accordance with AMM task: 26-21-00-710-801.

    1. If system checks are good, do close out.
    2. If system checks are not good, replace the APU fire handle.

  6. Do close out.

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