02/26/21
Message Overview:
Message Description:
No Air Data Computer 2 (ADC-2) Input to Horizontal Stabilizer Electronic Control Unit (HST ECU) on R-GP-5.
Possible Causes:
- Right Air Data Computer (ADC) (A2)
- Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU) (A130)
- Right Input/Output Concentrator (R IOC) (A4-IOC2)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin:
- AW300-27-0081 - Spoiler Electronic Control Unit (SECU) and Horizontal Stabilizer Electronic Control Unit (HSTECU) - Cold Temperature Circuit Breaker Reset Procedure
Forum Articles/Infoservice/Newsletter: None
NOTE: Before troubleshooting this problem, reset HST ECU by pulling CB1-B15 & CB2-B13 and then resetting CBs with aircraft power on. Continue with troubleshooting if fault persists.
NOTE: Before performing wiring checks all LRU (line replaceable units) must be removed from rack connectors. BD-100 Schematic Manual 31-45-00 page 20 will aid in the identification of all LRUs on R-GP-5 Bus.
Quick Links:
| 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 |
| Removal of the Air Data Computer | AMM 34-13-01-000-801 |
| Installation of the Air Data Computer | AMM 34-13-01-400-801 |
| Functional Test of the Air Data Computer | AMM 34-13-01-720-801 |
| 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:
- Perform an ADC reversion to ADC 1 on the cockpit reversionary selection panel (equivalent to swapping ADCs). Is the fault still present on the same side?
- If YES, continue with next step.
- If NO, replace ADC 2.
NOTE: You may elect to physically swap ADC 2 with ADC 1 to confirm faulty unit and replace if required.
- Swap the Input/Output Concentrator (IOC) cards. Is the fault still present on the same side?
- If YES, continue with next step.
- If NO, replace defective IOC.
- Perform a wiring check of the data bus between ADC 2 and Integrated-Avionics Processor System (IAPS) right IOC.
- If wiring defects are found, repair defective wiring as required and do close out.
- If no defects are found, continue with next step.
- Replace the Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU).
- Do close out.