EASA SIB 2008-13: WITHDRAWN - REPLACED BY EASA AD 2009-0090

What to do

Operators should verify the serial numbers of TU250 CS boards installed on MAKILA 1A and 1A1 engines and avoid having suspect boards in both engines of the same helicopter unless they have demonstrated over 200 hours of trouble-free operation. Ultimately, all suspect boards should be replaced with boards outside the affected serial number range as recommended in TURBOMECA Mandatory Service Bulletins 298 73 0809 and 298 73 0810. Compliance with EASA AD 2007-0144 remains mandatory.

Summary

EASA Safety Information Notice 2008-13 addresses a manufacturing issue with the Engine Control Unit (ECU) Comparator/Selector (CS) boards incorporating modification TU250 on TURBOMECA MAKILA 1A and 1A1 turboshaft engines. These engines are installed on EUROCOPTER AS 332 series helicopters. The notice informs about erratic engine behavior linked to certain CS boards within a specific serial number range and provides guidance on mitigating this issue.

What changed

The notice highlights that some TU250 CS boards suffer from quality control lapses in varnishing, causing unexpected N1 speed variations and warning light activations. It introduces a two-step approach: first, avoiding installation of suspect CS boards in both engines of the same helicopter unless they have over 200 hours of trouble-free operation; second, recommending replacement of all suspect boards regardless of operating time with boards outside the affected serial number range.

Why it matters

This information is critical for operators and maintenance organizations to prevent potential hazardous engine behavior that could affect helicopter safety, especially in twin-engine configurations. Understanding and addressing the issue ensures compliance with EASA AD 2007-0144 and helps maintain engine reliability and flight safety.

What to do

Summary

What changed

Why it matters

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