02/24/21
Message Overview:
Message Description:
L-CDU-6 data absent at T-VHF and NOT absent at least 3-of (L-IOC, L-NAV(ADF/VIR), L-DME). Not incl: L-TDR, L-VHF and L-HF.
Possible Causes:
- Third VHF Communication Unit (VHF 3) (A10)
- Junction Box 3 (JB3)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the VHF Communication Unit | AMM 23-11-01-000-801 |
| Installation of the VHF Communication Unit | AMM 23-11-01-400-801 |
| Removal of the Junction Box (JB3) | AMM 24-63-09-000-802 |
| Installation of the Junction Box (JB3) | AMM 24-63-09-400-802 |
| Removal of the Control Display Unit (CDU) | AMM 34-61-05-000-801 |
| Installation of the Control Display Unit (CDU) | AMM 34-61-05-400-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset VHF 3 (CB3-E2) circuit breaker.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Do the wiring check of the ARINC 429 databus L-CDU-6 between CDU1 connector A69P1, through Junction Box 3, to VHF 3 connector A10P1. Repair/replace as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace VHF 3.
- Do close out.