2022 Pilatus PC-12/47E Engine Incident at Bern Airport

Incident Overview and Flight Details On 29 July 2022, a Pilatus Aircraft PC-12/47E, operated by the Swiss Confederation, was scheduled for an instrument flight from Bern, Switzerland, to Saarbrücken, Germany. The aircraft, a single-engine turboprop with a pressurized cabin, was equipped with a Pratt & Whitney PT6A-67P engine. The flight crew consisted of a 45-year-old pilot-in-command holding a Swiss commercial pilot license and a second pilot, along with two passengers. ## Sequence of Events During the initial start run, the pilot-in-command observed higher-than-usual interstage turbine temperatures (ITT) and aborted the takeoff. After consulting the engine emergency checklist and confirming that temperature limits were not exceeded, the crew prepared for a second attempt. During the second takeoff, elevated ITT readings persisted, and the pilot noted that the engine was not producing the expected power. The pilot aborted the flight and directed the aircraft into the eastern traffic pattern. During the final approach, occupants observed sparks from the engine exhaust. The aircraft landed safely on Runway 14 at approximately 09:20 local time. ## Aircraft and Maintenance History The aircraft, manufactured in 2015 with serial number 1515, had 1,840 engine hours and 2,958 landings at the time of the incident. It had undergone extensive maintenance on 22 July 2022, including a six-month inspection, compressor wash, and propeller replacement. Following this maintenance, the operator reported intermittent yellow caution lights for the engine, which were attributed to high ambient temperatures and air conditioning use. ## Investigation and Findings The investigation was delegated to the German Federal Bureau of Aircraft Accident Investigation (BFU) in 2023 due to concerns regarding the independence of the Swiss investigation. Data from the aircraft's Lightweight Data Recorder showed ITT readings exceeding 800°C during the start and initial climb, with notable peaks during the final approach. A borescope inspection after the landing revealed damage to the compressor. Subsequent examination of the engine at Pratt & Whitney Canada in Saint-Hubert, Quebec, found small metallic deposits in the gas generator case and minor impact marks on the power turbine blades. The inlet screen was intact, though a small metal fragment was found inside it.