Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Hamilton Sundstrand Power Systems (formerly Sundstrand Power Systems, Turbomach, and Solar) T-62T series auxiliary power units (APU's) with compressor wheel part number (P/N) 100636-1 installed. This proposal would require the replacement of compressor wheels P/N 100636-1. This proposal is prompted by a manufacturer's stress analysis that indicates stress levels high enough to initiate and drive crack growth in these compressor wheels. The actions specified by the proposed AD are intended to mandate the replacement of the affected compressor wheels, which if not replaced, could result in uncontained compressor wheel failure and damage to the airplane.