Airworthiness Directive · Amendment 39-12742 · Honeywell International, Inc., (Formerly AlliedSignal, Inc., Textron Lycoming, Avco Lycoming, and Lycoming) Former Military T53 Series Turboshaft Engines
Honeywell International, Inc., (Formerly AlliedSignal, Inc., Textron Lycoming, Avco Lycoming, and Lycoming) Former Military T53 Series Turboshaft Engines
This airworthiness directive (AD) is applicable to Honeywell International, Inc. (formerly AlliedSignal, Inc., Textron Lycoming, Avco Lycoming, and Lycoming) former military T53 series turboshaft engines with centrifugal compressor impellers part numbers (P/N's) 1-100-078-07 or 1-100-078-08 installed. These engines are installed on, but not limited to, Bell Helicopter Textron manufactured AH-1, UH-1, and SW-204/205 (UH-1) series surplus military helicopters that have been certified in accordance with Secs. 21.25 or 21.27 of the Federal Aviation regulations (14 CFR 21.25 or 21.27).
This amendment adopts a new airworthiness directive (AD), that is applicable to Honeywell International, Inc., (formerly AlliedSignal, Inc., Textron Lycoming, Avco Lycoming, and Lycoming) former military T53 series turboshaft engines. This amendment requires conducting a revised operating cycle count (prorate) and initial and repetitive inspections for cracks of centrifugal compressor impellers. This amendment is prompted by a report of a military surplus helicopter that experienced low-cycle fatigue failure of the centrifugal compressor impeller, resulting in an uncontained engine failure. The actions specified by this AD are intended to prevent centrifugal compressor impeller failure, which can result in an uncontained engine failure, in-flight engine shutdown, or damage to the helicopter.
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.
