AD/PC-12/57 Nose Wheel Steering Torque Tube (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.

Pilatus PC-12 Series Aeroplanes

AD/PC-12/57 Nose Wheel Steering Torque Tube 5/2009

Applicability:

Models PC-12, PC-12/45 and PC-12/47 aircraft, Manufacturer Serial Numbers 101 through 544 and 546 through 888.

Model PC-12/47E aircraft, Manufacturer Serial Numbers 545 and 1001 through 1080.

Requirement:

Action in accordance with the requirements of EASA AD 2009-0060.

Note:  PILATUS PC-12 Service Bulletin No. 32-021 original issue, or later EASA approved revision, refers.

Compliance:

As specified in the Requirement document, with a revised effective date of
7 May 2009.

This Airworthiness Directive becomes effective on 7 May 2009.

Background:

The EASA received several reports of in-service cracked nose wheel steering torque tubes.  A reduced wall thickness produced during the manufacturing process has been determined to be the initial cause.  Additionally, all the affected torque tubes have been found to have evidence of fatigue cracking.  Such cracking, unless detected, could lead to failure of the torque tube and result in loss of steering on the ground and consequent unsafe condition.

David Villiers
Delegate of the Civil Aviation Safety Authority

26 March 2009