AD/Arrius/7 High Pressure Turbine (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Turbomeca Turbine Engines - Arrius Series

AD/ARRIUS/7 High Pressure Turbine 6/2005 TX

Applicability:

Turbomeca ARRIUS 2F engines which are fitted to Eurocopter EC120B helicopters.

Requirement:

Do not operate engines fitted with number 2 modules as listed in Alert Fax TURBOMECA 057/05/DSO/TM.

Engines may be operated after the engine has received inspection/rework at an approved repair centre.

Note:  DGAC AD UF-2005-073 EASA approval No. 2005-3835 dated 27 April 2005 refers.

Compliance:

From the effective date of this Directive.

This Airworthiness Directive becomes effective on 30 April 2005.

Background:

Following an accident involving an EC1 208, the initial investigation of the Arrius 2F engine showed that one HP blade was totally released from the HP disk.  This blade was contained inside the containment ring.

The preliminary examination of the engine parts showed that the standard of one ferrule initiated a disturbance in the secondary air system used to cool the HP turbine.

James Coyne
Delegate of the Civil Aviation Safety Authority

28 April 2005