AD/Arrius/8 Free Turbine Overspeed Protection System (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/8 Free Turbine Overspeed Protection System 7/2005 TX

Applicability:	Arrius 1A and 1E turboshaft engines.
Requirement:	Check the operation of the stop circuit of the free turbine overspeed protection system in accordance with Turbomeca Mandatory Alert Service Bulletin A319 77 0804 dated 24 March 2005 or later revision approved by the French Direction Générale de l’Aviation Civile (DGAC).
Note:  DGAC AD UF-2005-063 R1 (EASA approval 2005-4011 dated 4 May 2005) refers.
Compliance:	Initially within 25 hours time in service after the effective date of this Directive, if not previously accomplished before the effective date of this Directive, but no later than 31 May 2005 and thereafter each time maintenance task 77-30-01 is performed in accordance with the schedule defined in Chapter 05-10-02 of the Arrius 1 Maintenance Manual (MM).
This Airworthiness Directive becomes effective on 13 May 2005.
Background:	The DGAC has advised of a malfunction in the stop circuit of the free turbine overspeed protection system that cannot be detected through the test defined by task 77-30-01 of the Arrius 1 MM.  A malfunction of this system may lead to an un-contained release of high energy debris from the free turbine during a free turbine overspeed event.

James Coyne
Delegate of the Civil Aviation Safety Authority

11 May 2005