AD/Arrius/13 Gas Generator Front Bearing (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/13 Gas Generator Front Bearing 6/2007

Applicability:

ARRIUS 2F Turboshaft engines.

Note 1:  These engines are installed on but not limited to Eurocopter EC 120B helicopters.

Requirement:

Incorporate Turbomeca Modification Tf12 in accordance with paragraph 2 of Turbomeca Mandatory Service Bulletin No. 319 72 4102 update No.1 or later approved revision.

Note 2:  EASA AD 2007-0057 dated 1 March 2007 refers.

Compliance:

Within 30 days after the effective date of this AD unless previously accomplished.

This Airworthiness Directive becomes effective on 7 June 2007.

Background:

This AD is in response to an uncommanded in-flight shut down which occurred following the seizing of the gas generator.  The seizing of the gas generator was caused by the fracture of the separator cage of the gas generator bearing, due to high-cycle fatigue cracks initiated in the lubrication slots of the separator cage.

David Punshon
Delegate of the Civil Aviation Safety Authority

26 April 2007