02/26/21
Message Overview:
Message Description:
Both Input/Output Concentrators (IOC) Left and Right are not receiving ARINC data from Horizontal Stabilizer Electronic Control Unit (HST ECU).
Possible Causes:
- Horizontal Stabilizer Trim Electronic Control Unit (HST ECU) (A130)
- Left Input/Output Concentrator Unit (IOC) (A4-IOC1)
- Right Input/Output Concentrator Unit (IOC) (A4-IOC2)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Quick Links:
| Removal of the Stall Protection Computer | AMM 27-32-01-000-801 |
| Installation of the Stall Protection Computer | AMM 27-32-01-400-801 |
| Removal of the Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU) | AMM 27-41-21-000-801 |
| Installation of the Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU) | AMM 27-41-21-400-801 |
| Operational Test of the Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU) | AMM 27-41-21-710-801 |
| 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 |
| Operational Test of the Input/Output Concentrator Unit (IOC) | AMM 31-45-05-710-801 |
| 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:
- Pull the HST ECU breaker CB1 - B15 and breakerCB2 - B13, reset after a couple seconds. This will re-boot the HST ECU.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace HST ECU.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Perform wiring check between HST ECU and IOCs/IAPS. Repair as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace Input/Output Concentrator Unit (IOC)/IAPS.
- Do close out.
