What happened
On August 4, 2018, a DG-600 18m glider, registration SP-3713, departed from Rudniki airport for a planned flight route via Kielce-Masłów. While flying, the pilot observed rapidly developing thunderstorm clouds to the north and decided to abort the mission and return to Rudniki.
Approximately 20 km from the home airport, the aircraft entered an area of intense rainfall characterized by significant downward air currents, causing the glider to descend at rates of up to 10 m/s. Due to the heavy rain and reduced visibility, the pilot was unable to select an ideal landing site and eventually decided to perform an emergency landing in a plowed field at an altitude of approximately 200 m.
The landing was executed with a tailwind at a high speed of approximately 148 km/h. During the maneuver, the glider bounced twice on the soft ground. On the second impact, the right wingtip struck the terrain and was torn off. This impact caused the aircraft to rotate 180 degrees in the air, eventually coming to a stop facing the opposite direction of the initial approach. The pilot sustained no injuries.
The investigation
The PKBWL investigation examined the flight's GPS logs, meteorological data, and the aircraft's physical condition. The investigation established that the pilot had consulted with other pilots prior to the flight, who had warned of potential thunderstorms. The investigators analyzed the aerodynamic impact of the heavy rain on the glider's laminar profile and evaluated the pilot's decision-making process during the descent through the storm's outflow.