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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

03/28/25

Message Overview:

Message Name:

REFUEL/DEFUEL PANEL NORMAL & CHECK OIL LIGHTS ON OR FLASHING

Message Code: 793OBS001
Effectivity: AIRCRAFT 20501 - 20999
System: Oil: Indicating
Associated CAS: None
System Description: 28-41-00 - Fuel Management and Quantity Gauging System (FMQGS)
79-30-00 - Indicating
Schematic Diagram: SSM 28-41-00-101 - Fuel Management and Quantity Gauging System (FMQGS)
SSM 79-31-00-101 - Oil Indication System
Wiring Diagram: WM 28-41-01-1_001 - Sheet 1 - Fuel Quantity Computer - ALL
WM 71-50-01-1_001 - Sheet 1 - Engine Electrical Harness - ALL
WM 71-50-01-1_003 - Sheet 3 - Engine Electrical Harness - ALL
WM 79-31-05-1_001 - Sheet 1 - Oil Measuring - ALL

Message Description:

The Fuel Quantity and Gauging Computer (FQGC) has detected a discrepancy in the Left/Right Engine Oil Probe circuit. The fault can be triggered by the presence of water in the probe.

Possible Causes:

  1. Oil Level Probe
  2. Fuel Computer System Unit (A57)
  3. Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin:

  • AW300-79-0128 - No Fault Found Reduction Initiative and Troubleshooting Information - Engine Remote Oil Level Sensor

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

NOTES:

  • The oil level probes are connected to the Fuel Quantity Gauging Computer (FQGS). Oil gauging calculations are independent of fuel gauging. Oil level signals are transmitted to the Refuel/Defuel Panel (RDP) via ARINC 429 bus.

    • The 'NORMAL' and 'CHECK OIL' lights being ON at the same time on the RDP indicates a fault in the oil level probe or circuitry or the measurements are out of tolerance for that side.
    • Flashing lights indicates that the computations are done using default settings and that the system requires calibration.

  • Visually ensure oil tanks are full per sight glass markings and add oil as required.
  • Fill the Detailed FQGC Troubleshooting Report if Fuel Quantity Gauging Computer (FQGC) pn 738360-1-2 is replaced.

Quick Links:

Quantity Check of the Engine Oil Tank (With the Sight Glass) AMM 12-14-01-610-801
Quantity Check of the Engine Oil Tank (With the Refuel/Defuel Control Panel) AMM 12-14-01-610-802
Removal of the Fuel Quantity Computer AMM 28-41-01-000-801
Installation of the Fuel Quantity Computer AMM 28-41-01-400-801
Calibration of the Remote Oil-Indicating System AMM 79-31-00-820-801
Removal of the Oil Level Probe AMM 79-31-13-000-801
Installation of the Oil Level Probe AMM 79-31-13-400-801
Intertechnique Oil Probe Cleaning CMM 79-32-01-100-801-A01
Honeywell Inspection of Oil Probe LMM 72-60-01-200-005-A01
Safety Precautions - Maintenance Practices - ALL SPM 20-00-01-02
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02
Electrical Connectors - Description and Operation - ALL SPM 20-20-00-00

Troubleshooting Recommendations:

  1. Make sure Refuel/Defuel Panel is set to OFF and reset the Fuel Quantity System breakers (CB3-C3, CB4-C3). Is the fault message still present?

    1. If NO, do close out.
    2. If YES, continue with next step.

  2. Visually ensure oil tanks are full per sight glass markings and add oil as required. Is the fault still present?

    1. If NO, do close out.
    2. If YES, continue with next step.

  3. Verify that there is no EICAS 'FUEL QUANTITY FAIL' or 'FUEL QUANTITY FAULT'

    1. If a fault is found, it must be addressed first.
    2. If none are found, continue with next step.

  4. Verify that the MDC CURRENT FAULT(s) do not show any of the following faults:

    R/D Panel - No Communication with FQGC B3-006796
    L ENG OIL PROBE B3-007114
    R ENG OIL PROBE B3-007837

    1. If a fault is found, it must be addressed first.
    2. If none of these faults are found, continue with next step.

  5. Remove the suspected Oil Level Probe.
  6. Do the visual inspection of the Oil Level Probe - Subtask 72-60-01-200-005-A01 as per Honeywell LMM 72-05-12 (Honeywell's website).
  7. Do the cleaning of the Oil Level Probe - Task 79-32-01-100-801-A01 as per Intertechnique CMM; 79-32-01 (https://tpi.services.zodiacaerospace.com).
  8. Install the suspected Oil Level Probe and do the calibration of the Remote Oil-Indicating System. Is the fault still present?

    1. If NO, do close out.
    2. If YES, continue with next step.

  9. Interchange the Oil Probes and do the calibration of the Remote Oil-Indicating System. Is the fault message still present?

    1. If NO, do close out.
    2. If YES, continue with next step.

  10. Do wiring check between the FQGC (A57) and the suspected Oil Level Probe for the following wiring:

    From To Result
    A57AP1-25 (left) W4P2-2
    A57AP1-33 (left) W4P2-3
    A57AP1-34 (left) W4P2-1
    A57AP1-23 (right) W4P2-2
    A57AP1-33 (right) W4P2-3
    A57AP1-34 (right) W4P2-1

    1. If the check is not satisfactory, repair/replace defective wire/harness.
    2. If the check is satisfactory, continue with next step.

  11. Replace Fuel Quantity Gauging Computer (A57).
  12. Do close out.

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