FUEL COMPUTR FAIL
(Caution)

When one of the following conditions occur:

1. Fuel Management and Quantity Gauging Computer (FMQGC) CH A and CH B ARINC output bus to DAU failed (external - No CAIMS messages).
2. Fuel Management and Quantity Gauging Computer (FMQGC) CH A and CH B internal failure.
3. Fuel Management and Quantity Gauging Computer (FMQGC) CH A and CH B electrical power failure (external).

• Fuel Management and Quantity Gauging Computer (FMQGC)
• Secondary Power Distribution Assembly (SPDA)
• Data Acquisition Units (DAU) 1
• Data Acquisition Units (DAU) 2
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Using the PMAT, access the CAIMS Active Faults/Stored Faults
2. Select displayed CAIMS message below:
   Select an Item2844674PK - FMQGS COMPUTER CH A LMS/WRG FAULT2844675PK - FMQGS COMPUTER CH B LMS/WRG FAULT2844676PK - FMQGS COMPUTER/WRG FAULT284467APK - FMQGC CH A INPUT/OUTPUT PROCESSOR FAULT284467BPK - FMQGC CH B INPUT/OUTPUT PROCESSOR FAULT284467CPK - FMQGS CH B COMPUTER/WRG FAULT284467DPK - FMQGS CH A COMPUTER/WRG FAULT284467EPK - FMQGS COMPUTER CH A AUTOCAL #1/WRG FAULT284467FPK - FMQGS COMPUTER CH A AUTOCAL #21/WRG FAULT284467GPK - FMQGS COMPUTER CH B AUTOCAL #1/WRG FAULT284467HPK - FMQGS COMPUTER CH B AUTOCAL #2/WRG FAULT

NOTE: If the reporting LRU for this CAS message displayed in RED on the PMAT or if no associated ACTIVE FAULT is displayed on the PMAT, do the troubleshooting below.

1. Check FMQGC output communication with the DAUs. Using CAIMS System Diagnostic pages for each FMQGC channel. Ensure data page information is not red. If data is red, the communication between DAU or PMAT and the FMQGC is invalid. You can also access LRU STATUS in the PMAT Start menu and select the FMQGC. Both Channels of the FMQGC and their relation to the DAUs will be displayed.
2. Check FMQGC CH A and CH B ARINC outputs data communication validity and activity for DAU 1 and DAU 2.

   1. If FMQGC CH A communications is invalid, continue with next step.
   2. If FMQGC CH B communications is invalid, go to step 4.

3. Swap DAU 1 and DAU 3. Is the fault still present?

   1. If YES, continue with next step
   2. If NO, replace defective DAU

4. Swap DAU 2 and DAU 4. Is the fault still present?

   1. If YES, continue with next step
   2. If NO, replace defective DAU

5. Perform wiring check between FMQGC CH A and DAU 1.

   1. If wiring check is not satisfactory, repair defective wiring as required
   2. If no wiring defect is found, continue with next step

6. Perform wiring check between FMQGC CH B and DAU 2.

   1. If wiring check is not satisfactory, repair defective wiring as required
   2. If no wiring defect is found, continue with next step

7. Replace the FMQGC
8. Do close out.