Swiss Investigation of PA-22-150 Stall Accident at Langenthal (HB-OPL)

Overview and Aircraft Details On 24 April 2017, a Piper PA-22-150 Tri-Pacer, registration HB-OPL, was involved in an accident at Flugplatz Langenthal (LSPL) in the municipality of Bleienbach, Switzerland. The aircraft was a four-seat, single-engine high-wing model with fixed tricycle landing gear, operated privately. The pilot held a European Aviation Safety Agency (EASA) Private Pilot Licence (Aeroplane) issued by the Federal Office of Civil Aviation (BAZL). The aircraft had undergone partial restoration in January 2017, including a complete overhaul of the fuselage section. ## Flight Sequence and Accident The flight was a technical check flight conducted under Visual Flight Rules (VFR). At 16:10 local time, the pilot initiated takeoff from runway 23. After an estimated ground roll of approximately 180 meters, the aircraft lifted off and climbed steeply. The pilot reported encountering a gust of wind. In response, the pilot pushed the control yoke fully forward and began adjusting the elevator trim in the down direction. The aircraft climbed at an estimated speed of about 30 knots to a height of approximately 10 meters. The aircraft then rolled over its right wing and impacted the ground, triggering the Emergency Locator Transmitter (ELT). No fire occurred. Both occupants exited the aircraft through the right door under their own power. ## Findings and Probable Cause The Swiss Transportation Safety Investigation Board (STSB) determined that the accident was caused by a loss of control due to a stall shortly after the aircraft left the ground. The pilot had inadvertently manipulated the elevator trim in the wrong direction. This action reduced the effectiveness of the elevator, making it impossible to reduce the angle of attack even with immediate control input. The resulting stall led to a loss of control, causing the aircraft to roll over its right wing and crash from a height of approximately 10 meters. The pilot sustained no injuries, while the passenger suffered a fracture of the eleventh lumbar vertebra. The aircraft was heavily damaged.