Airworthiness Directive · Amendment 39-9936 · Pratt & Whitney Canada PT6 Series Turboprop Engines
Pratt & Whitney Canada PT6 Series Turboprop Engines
Pratt & Whitney Canada (PWC) PT6 series turboprop engines manufactured after January 1, 1995, or any PT6 series engines that have had their compressor bleed-off valve (BOV) changed after January 1, 1995, and which are installed in single-engine aircraft including, but not limited to the following aircraft: Air Tractor AT, Ayres Turbo Thrush Commander, Cessna 208 Caravan, Argo Aircraft G169B, Embraer EMB-312 Tucano, Frakes AF-CAT, Pilatus PC-6, PC-7, PC-9, and PC-12, Schweitzer AG-CAT, Aerospatiale Socata TBM- 700, and Raytheon (Beech) T-34C.
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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
