Airworthiness Directive · Amendment 39-14369 · Hamilton Sundstrand Power Systems (Formerly Sundstrand Power Systems) Auxiliary Power Units Models T-62T-46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T-46C7A
Hamilton Sundstrand Power Systems (Formerly Sundstrand Power Systems) Auxiliary Power Units Models T-62T-46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T-46C7A
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.
The FAA is adopting a new airworthiness directive (AD) for 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. This AD requires removal from service of those compressor impeller assemblies at reduced service life limits. 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.
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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
