Airworthiness Directives; Pratt & Whitney Canada PT6 Series Turboprop Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney Canada (PWC) PT6 series turboprop engines. This action requires a one-time visual inspection of compressor bleed-off valves (BOVs) to determine if an affected supplier's code number is on the cover; and, if so, this AD requires the removal of the bleed valve cover assembly from the compressor bleed valve housing assembly and inspection of the cotter pin and the guide shaft pin. If the cotter pin or guide shaft pin is not acceptable, this AD requires modifying the compressor BOV or replacing it with a serviceable part. This amendment is prompted by reports of two malfunctions of compressor BOVs that resulted in inflight engine power reduction. The actions specified in this AD are intended to prevent engine power reduction due to malfunction of the compressor BOV, which could result in a forced landing and loss of the aircraft.