03/22/21
Message Overview:
Message Description:
L-GPS-1 bus data to L IOC is reported absent.
Possible Causes:
- Global Positioning Receiver 1 (LH) (A25)
- Input/Output Concentrator Unit (IOC) 1 (A4-IOC1)
- 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 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 Global Positioning Receiver | AMM 34-55-01-000-801 |
| Installation of the Global Positioning Receiver | AMM 34-55-01-400-801 |
| 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 GPS (CB1-A3) circuit breaker.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Swap GPSs.
- 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.
- Do wiring check of the ARINC 429 data bus L-GPS-1 form GPS 1 connector A25BP1 to IAPS connector A4P1.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Replace IAPS Card Cage.
- Do close out.