Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2017-18-14, which applies to certain Rolls-Royce Corporation (RRC) 250 model turboshaft engines. AD 2017-18-14 requires repetitive visual inspections and fluorescent penetrant inspections (FPIs) of the 3rd- stage turbine wheel and removal from service of the 4th-stage turbine wheel. Since the FAA issued AD 2017-18-14, the manufacturer redesigned the 3rd-stage turbine wheel. This proposed AD would require replacement of the 3rd-stage and 4th-stage turbine wheels. This proposed AD would also revise the applicability to add an additional turboshaft engine model. The FAA is proposing this AD to address the unsafe condition on these products.