EASA SIB 2025-10: Arriel 1 Engines — Module 03 — TU377 Modification Implementation

What to do

Operators of helicopters with Arriel 1B, 1D, and 1D1 engines having module 03 serial numbers listed in Appendix 1 should implement the TU377 modification as recommended by Safran HE Service Bulletin 292 72 0377. Operators and maintenance organizations should contact Safran HE to inform them of the modification status or module disposition. There is no mandatory compliance deadline, but prompt action is advised to mitigate safety risks.

Summary

EASA Safety Information Bulletin 2025-10 is an airworthiness bulletin addressing Safran Helicopter Engines Arriel 1B, 1D, and 1D1 engines equipped with module 03 (M03) installed on helicopters such as the Airbus Helicopters EC 130 and AS 350. The bulletin highlights the TU377 modification to prevent uncommanded in-flight shutdowns caused by rubbing between the centrifugal impeller and injection manifold. It provides a list of affected M03 serial numbers that still require retrofit.

What changed

The bulletin introduces the recommendation to embody the TU377 modification as detailed in Safran HE Service Bulletin 292 72 0377 Version F or later revisions. This modification reduces the length of the bonded felt on the injection manifold to prevent contact with the curvic coupling of the centrifugal impeller. It also calls for operators and maintenance organizations to report the retrofit status to Safran HE.

Why it matters

This bulletin is important because it addresses a safety concern related to uncommanded in-flight shutdowns in Arriel 1 engines, which can impact flight safety and operational reliability. Operators and maintenance organizations need to be aware of the affected modules to ensure timely retrofit and maintain engine airworthiness. Reporting retrofit status helps Safran HE track compliance and manage the fleet's safety effectively.

What to do

Summary

What changed

Why it matters

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