What happened
On September 4, 2016, at approximately 17:07 LMT, a Van’s RV-6A, registration SP-YUT, was conducting a training flight near Krosno (EPKR) during a local aviation event. After departing from runway 16, the aircraft flew south toward the Wrocanka area. While flying at an altitude of approximately 200 meters, the pilot executed a steep left turn with a bank angle reaching 90 degrees. During this maneuver, the aircraft entered a dynamic stall and subsequently entered the first phase of a left spin (likely a flat spin). The aircraft struck the ground at an angle of approximately 37 degrees. The impact ruptured the fuel tanks, causing the aircraft to ignite and resulting in the two fatalities on board.
The investigation
The PKBWL investigation examined the aircraft's technical condition, the pilot's experience, and the meteorological conditions at the time of the accident. Investigators analyzed the wreckage, noting that the aircraft broke into three distinct sections upon impact. An expert analysis of a broken elevator control screw confirmed that the failure was caused by the impact itself rather than fatigue. The investigation also reviewed the aircraft's weight and balance, finding that the takeoff weight exceeded the maximum allowable limit by 62 kg. Furthermore, the investigation assessed the weather data from the Krosno station, which recorded significant wind speeds and turbulence.
Findings
- The aircraft was in a serviceable condition with all necessary documentation and valid registration.
- The pilot had a valid PPL(A) license but had not flown extensively on this specific aircraft type recently.
- The pilot's flying style was noted as being very conservative, typically avoiding simulated emergency maneuvers or testing the aircraft's aerodynamic limits.
- The aircraft was overloaded, exceeding its maximum takeoff weight by 62 kg.
- Meteorological conditions were hazardous, characterized by strong southern winds and significant turbulence.
- The accident site was located within an area of orographic wave activity, specifically within a zone of active rotors.
- The primary cause of the accident was the dynamic stall of the aircraft after it encountered a rotor during a high-bank turn, leading to a spin and subsequent ground impact.