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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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03/03/21

Message Overview:

Message Name:

EGT SENSOR [CIRCUIT 1 XREF FAILURE]

Message Code:

4960148APU

Associated CAS:

APU FAULT
(Advisory)

Reporting LRU: Auxiliary Power Unit (APU) Full Authority Digital Engine-Controller (FADEC)
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:

The Auxiliary Power Unit (APU) Full Authority Digital Engine-Controller (FADEC) detected a failure in the Exhaust Gas Temperature (EGT) Sensor Circuit 1. Signal from EGT 1 is 150 °F less than signal from EGT 2 Sensor/Probe. Inhibited during Take-off and Landing.

Possible Causes:

  • Exhaust Gas Temperature (EGT) Sensor 1 (TC1-1)
  • Auxiliary Power Unit (APU) Full Authority Digital Engine-Controller (FADEC) (A108)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter:

  • Honeywell SIL-APU-87 - AIRBORNE AUXILIARY POWER - GAS TURBINE ENGINE-RE220GX APU Auto Shutdown in Heavy Rain

Notice To Operators (NTO): None

Flight Operation Notifications Manual (FONM): None

Quick Links:

Removal of the Engine Branched Wiring-Harness AMM 49-12-01-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Engine Branched Wiring-Harness AMM 49-12-01-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Removal of the Exhaust Gas Temperature (EGT) Sensor AMM 49-61-05-000-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Installation of the Exhaust Gas Temperature (EGT) Sensor AMM 49-61-05-400-801 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Gas Turbine Auxiliary CMM 49-24-35 [ Global Express ]  [ G5000 ]  [ Global XRS ]
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02 [ Global Express ]  [ G5000 ]  [ Global XRS ]

Troubleshooting Recommendations:

  1. Visually inspect the EGT 1 sensor for water, moisture or any damage that could cause a short between the posts.
  2. Perform continuity check at the EGT 1 sensor receptacle TC1-1 as follows:

    From To Expected Result Result
    TC1-1-A TC1-1-B >20 ohms
    TC1-1-C TC1-1-D >20 ohms

    1. If there is no continuity, go to step 4.
    2. If there is continuity, continue with next step.

  3. Perform wiring checks between sensors EGT 1 (TC1P1) and APU FADEC on connector (A108BP1).

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

  4. Replace EGT 1.
  5. Do close out.

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