03/10/21
Message Overview:
Message Description:
Integrated Air System (IAS) Controller (IASC)1-A bus is reported failed by both Remote Data Concentrator (RDC) channel, while IASC1-A is reported operative by at least one Data Concentrator Unit (DCU) channel.
Possible Causes:
- Remote Data Concentrator (RDC) (A13)
- Junction Box 3 (JB3)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Integrated Air System (IAS) Controller | AMM 21-31-01-000-801 |
| Installation of the Integrated Air System (IAS) Controller | AMM 21-31-01-400-801 |
| 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 Remote Data Concentrator (RDC) | AMM 31-41-05-000-802 |
| Installation of the Remote Data Concentrator (RDC) | AMM 31-41-05-400-802 |
| Wiring - Maintenance Practices - ALL | SPM 20-12-00-02 |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Reset EICAS RDC A circuit breaker CB1-D2 and EICAS RDC B circuit breaker CB2-D2. Is the fault message still present?
- If NO, do close out.
- If YES, continue with next step.
- Do wiring check from RDC (A13), through Junction Box 3 (JB3), to left IASC (A55) for the following wires:
From To Result Conn. A13FP1-2A Conn. A55P2-33 Conn. A13FP1-2B Conn. A55P2-6 - If the check is satisfactory, continue with next step.
- If the check is not satisfactory, repair wiring or replace defective Junction Box 3.
- Replace RDC (A13).
- Do close out.