• Pitch Trim and Rudder Travel Limiter Presentation
• Spoiler System Training Manual
• AW300-27-0077 - Troubleshooting Guide for Spoiler Electronic Control Unit and Horizontal Stabilizer Trim Electronic Control Unit

Message Name:

Nuisance Crew Alerting System (CAS) Messages

Spoiler Electronic Control Unit (SECU) and Horizontal Stabilizer Electronic Control Unit (HST ECU) - Cold Temperature Circuit Breaker Reset Procedure

This procedure is to provide operators with reset procedures pertaining to nuisance Crew Alerting System (CAS) messages affecting the Spoiler Electronic Control Unit (SECU) and Horizontal Stabilizer Trim Electronic Control Unit (HST ECU) during aircraft power-up in cold temperatures.

The following SECU and HST ECU related CAS messages (see list below) might be displayed during initial power-up of the day in temperatures near freezing or below. This condition is caused by the Dual Ported Random Access Memory (DPRAM), circuit which could latch-up in cold temperatures. The nuisance CAS messages can be cleared once the unit has achieved its normal operating temperature. The DPRAM circuit is installed in both the SECU and the HST ECU.

Typical CAS messages that may be displayed by the SECU on power-up:

• SPOILERS FAIL (caution)
• SPOILERS FAULT (Advisory)

Typical CAS messages that may be displayed by the HST ECU on power-up:

• PRI STAB TRIM FAIL (Caution)
• STAB TRIM FAULT (Advisory)
• RUDDER LIMITER FAIL (Caution)
• RUDDER LIMITER FAULT (Advisory)

NOTE: The stab trim position indication on EICAS can also flash on and off.

• Nuisance Crew Alerting System (CAS) Messages
• Spoiler Electronic Control Unit 1 (SECU) (A118)
• Spoiler Electronic Control Unit 2 (SECU) (A119)
• Horizontal Stabilizer Trim Electronic Control Unit (HST ECU) (A130)

Advisory Wire/Service Bulletin:

• AW300-27-0037 - Spoiler Electronic Control Unit (SECU) - Circuit Breaker Reset Procedure (20501 - 20999)
• AW300-27-0077 - Troubleshooting Guide for Spoiler Electronic Control Unit and Horizontal Stabilizer Trim Electronic Control Unit (20501 - 20999)
• AW300-27-0081 - Spoiler Electronic Control Unit (SECU) and Horizontal Stabilizer Electronic Control Unit (HSTECU) - Cold Temperature Circuit Breaker Reset Procedure (20501 - 20999)

Forum Articles/Infoservice/Newsletter: None

Should any of the above messages appear during initial aircraft power-up - the reset procedure in Troubleshooting Recommendations should be accomplished:

Effective November 2007, all returned SECU and HSTECU units have been screened for this condition and reworked to prevent any further occurrences.

If you are experiencing the above conditions on a regular basis, please advise your local Field Service Representative to confirm the fault. If the fault is confirmed, replace the affected SECU or HSTECU at your earliest convenience.

1. Reference CONTROL AND INDICATION SYSTEM - ADJUSTMENT/TEST TASK AMM 27-61-00-710-801 Spoiler System.
2. Should any of the above messages appear during initial aircraft power-up - the following reset procedure should be accomplished:

   1. For the SECU, wait 10 to 15 minutes after initial power-up then.perform the following:

      1. To determine which SECU is posting the message, go to the Flight Control synoptic page and check if one or more of the Multi-Function Spoilers (MFS) or Ground Spoiler (GS) panel boxes are amber or magenta. Do the breaker reset as follows:

         1. Reset SECU1 circuit breaker "SPOILER CTRL 1" CBP1-B9 if any of the inboard MFS and GS #2, #4, #5 and #7 surface indication are amber or magenta.
         2. Reset SECU2 circuit breaker "SPOILER CTRL 2" CBP2-B9 if any of the outboard MFS and GS #1, #3, #6 and #8 surface indication are amber or magenta.
            NOTES:

         • The identification of the boards is from left to right. The #1 indication is the outboard position of the left wing and the #8 indication is the outboard of the right wing.
         • The circuit breaker resetting should be performed when all the aircraft systems are operational, the hydraulic pressure available and prior to the Normal flight control check (ref. Quick Reference Handbook (QRH) Normal Procedures or Flight Crew Operating Manual).
         • It is not permissible to cycle the SECU1 or 2 circuit breakers in the air.
         • It is preferable to only cycle the breaker associated with the SECU that is posting the start-up fault.
         • Ensure the Radio Altimeter is providing valid data; otherwise the message(s) will persist.

   2. For the HSTECU, wait 10 to 15 minutes after initial power-up then perform the following:

      1. Pull "PRI STAB TRIM / RUD LIM" LCBP-B15 and "SEC STAB TRIM / RUD LIM" RCBP-B13 and wait 10 seconds. Push-in both circuit breakers.
         NOTE: It is not permissible to cycle the HSTECU circuit breakers in the air.