02/24/21
Message Overview:
Message Description:
DR-IOC-4 (FMC) input to DATALINK inactive and FMC 2 is active to IOC and SVC.
Possible Causes:
- Left Radio Interface Unit (RIU) 1 (A17)
- Configuration Connector J2000
- 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 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset RIU 1A (CB1-B5) and RIU 1B (CB1-B4) circuit breakers.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do wiring check of ARINC 429 data bus R-IOC-4 from RIU1 connector A17P2, through Config connector J2000, to IAPS connector A4P101. Repair/replace as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace RIU 1.
- Do close out.