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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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07/06/21

Message Overview:

Message Name:

APU SLOW START

Message Code: 496OBS005
Effectivity: All
System: Auxiliary Power Unit (APU) Automatic Control System
System Description: 49-60-00
Schematic Diagram: 49-61-00 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wiring Diagram: 49-61-01 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Message Description:

There is a high resistance between the Auxiliary Power Unit (APU) Full-Authority Digital Engine-Controller (FADEC) and the APU Starter. Experience has shown that (assuming the sense circuit wiring is intact) the problem is Starter Brush wear/sticking.

Possible Causes:

  • Starter Motor (B55)
  • Starter Brushes
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin:

Forum Articles/Infoservice/Newsletter:

  • Honeywell Sil APU-99 - Electronic Control Unit (ECU) "No Fault Found" Removals
  • Honeywell Sil APU-137 - AIRBORNE AUXILIARY POWER-GAS TURBINE ENGINE-Introduction of a field cleaning procedure for the RE220 APU starter PN: 2704554

Quick Links:

Removal of the Starter Motor AMM 49-42-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Starter Motor AMM 49-42-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Cleaning of the Starter Motor of Brush Dust Material AMM 49-42-01-110-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Measure the resistance across the starter terminals with an ohmmeter while manually rotating the starter with the HAND CRANK ACCESS.

    1. If resistance is less than 1000 ohms, go to step 3.
    2. If resistance is more than 1000 ohms, continue with next step.

  2. Clean Starter Brushes.

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

  3. Replace Start Motor.
  4. Do close out.

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