Airworthiness Directives; Pratt & Whitney Canada PT6A-25C and -114A Series Turboprop Engines

This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney Canada (PWC) PT6A-25C and -114A turboprop engines. This amendment will require initial and repetitive visual inspections, and eventual replacement of the compressor bleed valve assembly, with a redesigned valve assembly for -114A and -25C engines. This amendment is prompted by reports of two occurrences of uncommanded engine power loss. The actions specified by this AD are intended to detect wear in the compressor bleed valve assembly which may cause valve orifice blockage, resulting in a loss of power, an inability to accelerate the engine, and an in-flight shutdown.