02/26/21
Message Overview:
Message Description:
Spoiler Electronic Control Unit 1 (SECU1) input fault detected by Horizontal Stabilizer Electronic Control Unit (HST ECU). This logic will set a STAB TRIM FAULT if one of the HSTECM-1 or HSTECM-2 is invalid, but not both. If both, the HSTECM-1 or HSTECM-2 are invalid, the primary channel is assumed failed, and a different message will be annunciated. Similarly, the logic will set a STAB TRIM FAULT if one of the secondary valid discrete, or one of the analog stab position signals, is failed, but not both.
Possible Causes:
- Horizontal-Stabilizer-Trim Electronic-Control Unit (HST ECU) (A130)
- Spoiler Electronic-Control Unit 1 (SECU) (A118)
- Left Input/Output Concentrator (IOC) (A4-IOC1)
- 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
- AW300-27-0302 - SPOILERS FAULT EICAS Message Caused by TQA Idle Switch
Forum Articles/Infoservice/Newsletter:
- Perform the AW300-27-0081 reset procedure for the HST ECU if the message is displayed during initial power-up in cold temperature. The stab trim position indication on EICAS can also flash on and off.
- If the aircraft is powered up with > 8 degrees of aileron, the STAB TRIM FAULT will post. This can be verified by putting on hydraulics and looking at the spoiler synoptic page, typically the outboard spoiler the yoke is tilted towards will go amber after their self-test. Center the yoke and power-up the aircraft.
Quick Links:
| Electrical Rigging of the Pitch Trim System | AMM 27-41-00-820-801 |
| Rigging Check of the Pitch Trim System | AMM 27-41-00-220-801 |
| 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 Spoiler Electronic-Control Unit (SECU) | AMM 27-61-05-000-801 |
| Installation of the Spoiler Electronic-Control Unit (SECU) | AMM 27-61-05-400-801 |
| Electronic Rigging of the Spoiler Electronic-Control Unit (SECU) | AMM 27-61-05-820-801 |
| Electronic Rigging of the Spoiler Electronic-Control Unit (SECU) | AMM 27-61-05-820-802 |
| 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:
- Select the flight controls synoptic page and look for magenta or amber spoiler position indications. #1 SECU reports inboard Multi-Function and Ground Spoiler Information. This verifies the system is not seeing the spoiler information.
- Pull the #1 SECU breaker CB1 - B9, reset after a couple seconds. This will initiate the Power-On BIT test or PBIT. Some clunking will be heard on the wing during this test, CAS message SPOILER FAULT (cyan) will post and that CAS will clear along with the STAB TRIM FAULT (cyan).
- If the STAB TRIM FAULT message with the B3-006879 MDC fault and a spoiler message are posted, continue by following the troubleshooting steps associated with the MDC equation of that spoiler message.
- Do wiring checks (data bus) between SECUs, HST ECU, JB1 and JB2. Repair as required.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Swap SECUs (Spoiler system must be rigged after SECU replacement).
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace HST ECU.
- Do close out.