1. Fuel Management and Quantity Gauging Computer (FMQGC) internal fault of both channels including:

   • Input/Output (I/O) processors failed;
   • Main processor failed;
   • Communication between main processor and I/O processor failed; or
   • Probe excitation auto calibration check failure

2. FMQGC Channel A and Channel B electrical power failure (external).

• Fuel Management and Quantity Gauging Computer (FMQGC) (A47)

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. FMQGC internal faults can be checked using CAIMS as show in CAIMS image.
2. Loss of 28 VDC power source to the FMQGC CH A and CH B will set the FMQGS COMPUTER/WRG FAULT, FMQGS COMPUTER CH A and CH B LMS/WRG FAULT CAIMS messages, and FUEL COMPUTER FAIL CAS messages.
3. FMQGC re-racking procedure.

   1. Intermittent FMQGC issues are commonly caused by poor installation of the computer in the mounting tray. The FMQGC must be re-installed if movement of the unit or harness changes the failure symptoms. The FMQGC pins and mounting tray receptacle have minimal engagement tolerance. Furthermore, the special coaxial pins/sockets used for the fuel probe excitation circuit require additional force to fully engage them. Proper installation and racking of the FMQGC is vital to the operation of the fuel system.
   2. Install the FMQGC in its mounting tray as follows:

      1. Slide the FMQGC straight into the mounting tray until connectors engage.
      2. Engage the mounting tray turn buckles onto the front of the FMQGC.
      3. Screw in the turn buckles until the tension increase.
      4. Placing both hands on the front of the computer, push the FMQGC into the mounting tray.
      5. Repeat Step c and d several times until the turn buckles are tight and the FMQGC connectors are fully engaged.
         

1. Using CAIMS, verify if FMQGS COMPUTER CH A and CH B LMS/WRG FAULT are displayed:

   1. If YES, refer to FMQGS COMPUTER CH A and CH B LMS/WRG FAULT troubleshooting procedure.
   2. If NO, continue with next step.

2. Re-rack the FMQGC.

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

3. Reset FMQGC CH A and CH B power in a last chance to clear the fault.

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

4. Replace FMQGC.
5. Do close out.