Airworthiness Directives; Rolls-Royce Corporation Turboprop and Turboshaft Engines

We are superseding airworthiness directive (AD) 2012-14-06 for certain Rolls-Royce Corporation (RRC) 250-C20, -C20B, and -C20R/2 turboshaft engines. AD 2012-14-06 required a one-time visual inspection and fluorescent-penetrant inspection (FPI) on certain 3rd-stage and 4th-stage turbine wheels for cracks in the turbine blades. This new AD replaces the one-time visual inspection and FPI with repetitive visual inspections and FPIs. This AD also adds certain engine models to the applicability. This AD was prompted by the determination that the one- time inspections required by AD 2012-14-06 should be changed to repetitive inspections. We are issuing this AD to prevent failure of 3rd-stage and 4th-stage turbine wheel blades, which could cause engine failure and damage to the aircraft.