03/17/21
Message Overview:
Message Description:
No R-ADC-1 bus received at R-IOC and R-AHC.
Possible Causes:
- Right Air Data Computer (ADC) (A2)
- Junction Box 4 (JB4)
- Right Input/Output Concentrator Unit (IOC) 2 (A4-IOC2)
- Right Attitude Heading Computer (AHC) (A12)
- 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 Junction Boxes | AMM 24-63-01-000-802 |
| Installation of the Junction Boxes | AMM 24-63-01-400-802 |
| 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 Input/Output Concentrator Unit (IOC) | AMM 31-45-05-000-801 |
| Installation of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-400-801 |
| Removal of the Air Data Computer | AMM 34-13-01-000-801 |
| Installation of the Air Data Computer | AMM 34-13-01-400-801 |
| Removal of the Attitude Heading Computer (AHC) | AMM 34-21-01-000-801 |
| Installation of the Attitude Heading Computer (AHC) | AMM 34-21-01-400-801 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
| Electrical Connectors - Maintenance Practice - ALL | SPM 20-20-00-02 |
Troubleshooting Recommendations:
- Reset AIR DATA 2 (CB2-C1) circuit breaker.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Do the wiring check of the ARINC 429 databus R-ADC-1 from ADC 2 connector A2P1, through Junction Box 4, to AHC 2 connector A12P1 and IAPS Card Cage connector A4P101. Repair/replace as required.
- If system check passes, do close out.
- If fault remains, continue with next step.
NOTE: An internal short of any LRUs connected to this data bus might cause this failure.
- Swap ADCs.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Swap IOCs.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Swap AHCs.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Replace IAPS Card Cage.
- Do close out.