02/12/21
Message Overview:
Message Description:
L-GP-5 absent at 3-OF (A-DCU, SPC, TAWS, L-SECU, R-SECU, PSEU, HSTECU, RDC). LRUs not included: LDS, FCU, FQGC, IRS.
Possible Causes:
- Left Input/Output Concentrator Unit (IOC) 1 (A4)
- Junction Box 1
- Junction Box 2
- One or more LRUs in the L-GP-5 receiver(s) member(s) caused a short circuit
- 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 |
| Standard Practices - Wire Replace | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset L IAPS (CB1-B6) circuit breaker.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Swap IOCs.
- If system check passes, do close out.
- If fault remains, continue with next step.
- Do a wiring check of the ARINC 429 data bus L-GP-5 from IAPS connector A4P1, through Junction Box 1 and Junction Box 2, to all connected LRUs. 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.
- Replace IAPS Card Cage (ICC).
- Do close out.