AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive AD/TPE 331/50 and issues the following AD under subregulation 39.1 (1) of CAR 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. AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series AD/TPE 331/50 Amdt 1 First Stage Compressor Impeller 1/2003 Applicability: All TPE331 series engines fitted with part number 896223-1, -2, -3, -7 or part number 3107109-1, -2, -4 first stage compressor impellers. Requirement: 1. Weld repaired impellers: Remove from service weld repaired first stage compressor impellers detailed by serial number in Honeywell Service Bulletin TPE331-A72-2083 Revision 1. 2. Other then weld repaired impellers: Remove from service first stage compressor impellers in accordance with Honeywell Service Bulletin TPE331-A72-0971 Revision 2. Compliance: 1. For weld repaired impellers: a. As detailed in Honeywell Service Bulletin TPE331-A72-2083 Revision 1 with a revised effective date of 23 January 2003; or b. As detailed in Honeywell Service Bulletin TPE331-A72-0971 Revision 2 with a revised effective date of 23 January 2003. Whichever provides for the least number of cycles before removal. 2. For impellers other than weld repaired impellers: 1. As detailed in Honeywell Service Bulletin TPE331-A72-0971 Revision 2 with a revised effective date of 23 January 2003. This Amendment becomes effective on 23 January 2003. Background: This Directive has been issued to require removal from service of certain first stage compressor impellers. The requireme nt follows advice of an uncontained first stage compressor failure event. Impellers removed from service in accordance with this Directive are to be subjected to an inspection by AlliedSignal and if appropriate, reworking. Serviceable impellers will be returned to service with a nominated cycle life remaining. AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series AD/TPE 331/50 Amdt 1 (continued) This Amendment introduces compliance requirements for weld repaired first stage compressor impellers identified by serial number. The original issue of this Airworthiness Directive became effective on 9 November 1995. James Coyne Delegate of the Civil Aviation Safety Authority 28 November 2002 The above AD is notified in the Commonwealth of Australia Gazette on 18 December 2002.