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. Rolls Royce (Allison) Turbine Engines - AL501 Series AD/AL501/1 Second Stage Turbine Wheels 6/2006 Applicability: Rolls Royce (formerly DETROIT DIESEL ALLISON) Model 501-D13 series engines which incorporate P/N 6829072 and 6847112 second stage turbine wheels with the serial numbers listed as listed in FAA AD 75-22-05. Requirement: Remove from service second stage turbine wheels in accordance with the schedule in paragraphs l.A. B, C, and D of FAA AD 75-22-05. Note: FAA AD 75-22-05 Amdt 39-2391 refers. Compliance: As detailed in FAA AD 75-22-05 with a revised effective date of 8 June 2006. This Airworthiness Directive becomes effective on 8 June 2006. Background: This AD details the requirements for removal of certain second stage turbine wheels from service. James Coyne Delegate of the Civil Aviation Safety Authority 28 April 2006