AD/AL501/5 - Third and Fourth Stage Turbine Wheels (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.

Rolls Royce (Allison) Turbine Engines - AL501 Series AD/AL501/5 Third and Fourth Stage Turbine Wheels 6/2006

Applicability: Rolls Royce (formerly DETROIT DIESEL ALLISON) Model 501-D13/501-D13A/501-D13D/50l-D13E, and 501-D13H Engines equipped with third stage turbine wheel part numbers (P/N's) 6788833, 6842143, 6841223, and 6846553 or fourth stage turbine wheel P/N's 6738424 and 6843014. Requirement: 1. Unless previously accomplished, remove and classify all third and fourth stage turbine wheels with unknown carbide precipitation classifications in accordance with the procedures specified in Detroit Diesel Allison Commercial Overhaul Information Letter No. 349 Rev. 1 or later FAA approved revision.

2. Wheels both newly and previously classified with carbide precipitation classifications of "Heavy" must be removed from service in accordance with the maximum life limits specified in Compliance 2.

3. Wheels both newly and previously classified with carbide precipitation classifications of "Medium Heavy" must be removed from service in accordance with the maximum life limits specified in Compliance 3.