Summary
The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) 250-B and 250-C series turbofan and turboshaft engines with certain part numbers (PNs) of compressor adaptor couplings manufactured by Alcor Engine Company (Alcor), EXTEX Ltd. (EXTEX), RRC, and Superior Air Parts (SAP) installed. This proposed AD would require operators to remove from service affected compressor adaptor couplings. This proposed AD results from nine reports of engine shutdown caused by compressor adaptor coupling failure. We are proposing this AD to reduce the risk of failure of the compressor adaptor coupling and subsequent loss of all engine power.