Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Honeywell International, Inc., (formerly AlliedSignal, Inc., and Textron Lycoming) T5313B series, T5317 series, and former military T53 series, turboshaft engines having certain serial number centrifugal compressor impellers, installed. This proposal would require for T5313B series and T5317 series engines, initial and repetitive inspections of those compressor impellers, if installed. This proposal would also require 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 proposal would require the marking of those compressor impellers. This proposal is prompted by a report from the supplier that four centrifugal compressor impellers may have been inadvertently misidentified. The actions specified by theproposed 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.