02/02/21
Message Overview:
Message Description:
The channel A of the IASC-1 does not receive any data from the opposite IASC-2 channel A, but the IASC-2 channel B does receive data.
Possible Causes:
- Integrated Air System Controller (IASC1) (A55)
- Integrated Air System Controller (IASC2) (A56)
- Junction Box 1 (JB1)
- 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 |
| Operational Test of the Integrated Air System (IAS) Controller | AMM 21-31-01-710-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Check the #1 IAS controller circuit breaker CB1 D14 & CB1 E10, reset and re-check MDC for the bus fault.
- The #1 & #2 IASC A bus go from the IASCs to the DCU. The DCU then completes the data circulation on A-DCU-4 and B-DCU-4 buses. Check both A and B-DCU-4 bus wiring into #1 IASC.
- Suspect the #1 IAS controller, remove and replace Integrated Air System (IAS) Controller.
- Operational test of the Integrated Air System (IAS) Controller.

