Airworthiness Directives; Honeywell International, Inc., (formerly AlliedSignal, Inc. and Textron Lycoming) T5313B, T5317 Series, and T53 Series Turboshaft Engines

This amendment adopts a new airworthiness directive (AD), that is applicable to Honeywell International, Inc., (formerly AlliedSignal, Inc. and Textron Lycoming) T5313B, T5317 series and former military T53 series, turboshaft engines having certain serial number centrifugal compressor impellers, installed. This amendment requires for T53 series engines, a revised operating cycle count (prorate) for those compressor impellers if installed, and initial and repetitive inspections, with eventual compressor impeller replacement. In addition, this amendment requires the marking of those compressor impellers. This amendment is prompted by a report from the supplier that four centrifugal compressor impellers may have been inadvertently misidentified. The actions specified by this AD are intended to prevent premature failure of the impellers from being operated beyond their design service life, which could result in an uncontained engine failure, in-flight shutdown, or damage to the helicopter.