02/16/21
Message Overview:
Message Description:
Left IOC is reporting power failure for the Right IOC and 4 of the following LRUs are reporting a bus failure for the Right IOC (PFD 1, CDU 1, FMC 1, DCU 1, DCU 2, MFD 1, FGC 2, FMC 1).
Possible Causes:
- Right Integrated-Avionics Processor System (IAPS) Power Supply (PWR 2) (A4-PWR)
- Integrated-Avionics Processor System (IAPS) Card Cage (ICC) (A4)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Integrated Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-000-801 |
| Installation of the Integrated Avionics Processor System (IAPS) Card Cage (ICC) | AMM 31-45-01-400-801 |
| Removal of the Integrated Avionics Processor System (IAPS) Power Supply (PWR) | AMM 31-45-09-000-801 |
| Installation of the Integrated Avionics Processor System (IAPS) Power Supply (PWR) | AMM 31-45-09-400-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset L IAPS Circuit Breaker CB1-B6, R IAPS Circuit Breaker CB2-B6. Is the fault message still present?
- If YES, continue with next step.
- If NO, do close out.
NOTE: Before you open the IAPS circuit breakers, make sure that all Engine FADEC circuit breakers are open. If the Engine FADEC circuit breakers remain closed, Engine Igniters will activate. This can cause injury to persons and damage to equipment.
- With a multi-meter, verify presence of 28 VDC and GND for the IAPS PWR at the IAPS Card Cage (A4).
From To Expected Result Result Conn. A4P104 - H Aircraft Ground 28 VDC Conn. A4P104 - J Aircraft Ground Approx. 0Ω Conn. A4P102 - 21 Aircraft Ground Approx. 0Ω Conn. A4P102 - 26 Aircraft Ground Approx. 0Ω - If verification is satisfactory, continue with next step.
- If verification is not satisfactory, repair/replace defective component.
- Swap right IAPS PWR with left IAPS PWR. Is the fault message still present\?
- If YES, continue with next step.
- If NO, replace defective IAPS PWR.
- Replace IAPS card cage (A4).
- Do close out.