History of the Flight
On 5 March 2017, a Pilatus PC12/47 aircraft with registration VT-AVG, operated by Air Charter Services Private Limited, departed from Indira Gandhi International Airport, New Delhi, India, for a medical evacuation flight to Don Mueang International Airport, Thailand. The flight included a technical stop at Kolkata Airport, India, for refueling and customs clearance. The aircraft departed Kolkata at approximately 08:40 UTC with an estimated flight time of 3 hours 17 minutes at FL270. On board were two pilots and three passengers.
At 11:29:50, while at FL270 approximately 135 nautical miles from Don Mueang, the pilot observed oil spots on both windshields. Engine operation appeared normal at that time. At 11:45:13, the co-pilot reported engine issues to Bangkok Area Control Center and requested priority landing. The pilot subsequently requested descent and declared an emergency due to an oil sump leak.
Engine Failure and Emergency Landing
At 12:02:26, the pilot noted oil temperature and pressure indications at zero with warning lights, and the engine sound became louder. The pilot ordered an emergency declaration and descended. The co-pilot declared MAYDAY. The aircraft was cleared to fly direct to Don Mueang, but at 12:03:04 the pilot reported that the engine had seized. The pilot inquired about a nearby airport and was advised of Kamphaeng Saen Airport. Radar vectors were provided.
At approximately 12:15 UTC, the pilot made final contact 1 nautical mile from Kamphaeng Saen Airport. The aircraft made an emergency landing about 0.6 nautical mile from the threshold of runway 21, heading 063 degrees, and caught fire. The aircraft was totally destroyed. All five occupants were critically injured. The co-pilot died subsequently.
Wreckage and Investigation
The majority of the aircraft suffered fire damage. The engine and empennage were separated. The gearbox and propeller were detached from the engine. Examination of the reduction gearbox revealed damage to the first stage planet gear, ring gear, and sun gear, with metal chips accumulated at the magnetic chip detector. Oil residue and impurities were found on the torque limiter exterior. The scavenge pump interior showed scratches. Compressor turbine and power turbine discs were damaged. The left drive arm and right inboard actuator were damaged.
Inspections by advisers from Canada (Pratt & Whitney Canada) and Switzerland (Pilatus Aircraft Limited) were conducted. The investigation focused on the engine's reduction gearbox and oil system.
Injuries and Damage
All five persons on board were critically injured. The co-pilot died subsequently. The aircraft was destroyed by impact and fire. No other damage was reported.
Medical and Pathological Information
Toxicology tests were performed, but results are not specified in this report.
Safety Recommendations and Actions
The report includes safety recommendations and actions taken by the operator and authorities, as detailed in the final report.