2005-23-11: Compressor impeller assemblies

2005-23-11 Hamilton Sundstrand: Amendment 39-14369. Docket No. FAA- 2005-21719; Directorate Identifier. 2005-NE-19-AD. Effective Date (a) This airworthiness directive (AD) becomes effective December 14, 2005. Affected ADs (b) None. Applicability (c) This AD applies to Hamilton Sundstrand Power Systems (formerly Sundstrand Power Systems) auxiliary power units (APUs) models T-62T-46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T- 46C7A, with compressor impeller assembly, part number (P/N) 4502020 or 4502020A installed. These APUs are installed on, but not limited to, BAE Systems AVRO 146, Fokker 50, Saab 2000, and Saab 340 airplanes. Unsafe Condition (d) This AD results from two reports of uncontained failures of compressor impeller assemblies. We are issuing this AD to prevent an uncontained APU failure and damage to the airplane. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. (f) For APUs with compressor impeller assemblies that have 12,000 or more cycles-since-new (CSN) accumulated on the effective date of this AD, remove compressor impeller assemblies from service before accumulating 500 additional cycles. (g) For APUs with compressor impeller assemblies that have fewer than 12,000 CSN on the effective date of this AD, remove compressor impeller assemblies from service at or before accumulating 12,500 CSN. Alternative Methods of Compliance (h) The Manager, Los Angeles Aircraft Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Related Information (i) Hamilton Sundstrand Service Bulletins No. 4500090-49-33, dated January 6, 2005, No. 4500482-49-33, dated January 6, 2005, No. 4501578-49-22, dated January 13, 2005, No. 4501690-49-47, dated November 19, 2005, and No. 4501909-49-16, dated January 13, 2005, pertain to the subject of this AD.