02/16/21
Message Overview:
Message Description:
L-IOC-4 bus is reported failed at the L-RIU and SVC, while it is not reported failed at L-FMC and R-FMC.
Possible Causes:
- Junction Box 4 (JB 4)
- Synthetic Vision Computer (SVC) (A230)
- Left Radio Interface Unit (RIU) 1 (A17)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Radio Interface Unit (RIU) | AMM 23-51-21-000-801 |
| Installation of the Radio Interface Unit (RIU) | AMM 23-51-21-400-801 |
| 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 Synthetic Vision Computer (SVC) | AMM 34-34-01-000-801 |
| Installation of the Synthetic Vision Computer (SVC) | AMM 34-34-01-400-801 |
| 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 L IAPS (CB1-B6) circuit breaker.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do a wiring check of the ARINC 429 data bus L-IOC-4 from IAPS connector A4P3, through Junction Box 4, to RIU 1 connector A17P2 and to SVC connector A230AP1. Repair/replace as required.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Replace SVC.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Replace RUI 1.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Do close out.