What happened
On July 18, 2017, a student pilot was conducting his second solo thermal flight of the day in an SZD 30 Pirat glider. The flight began with a tow by an aircraft, initially performing a left turn at an altitude of approximately 100 meters. GPS data analysis revealed significant fluctuations in both airspeed (between 100 km/h and 140 km/h) and vertical speed (between -1.5 m/s and +4.5 m/s) during this phase.
As the tow aircraft transitioned to a westward heading, the glider's speed stabilized slightly, though vertical speed fluctuations continued. The student pilot reported difficulty controlling the glider and suspected mechanical damage, though he was focused entirely on piloting rather than monitoring airspeed. At an altitude of approximately 250 meters, roughly 2 km from the aerodrome, the tow aircraft began a right-hand turn. During this maneuver, the student reported hearing an unusual noise and experiencing a loss of control, likely caused by the aircraft entering a large area of turbulence. The student subsequently decided to release from the tow.
Following the release, at an altitude of approximately 350 meters, the student was instructed by a supervising instructor via radio to return to the aerodrome due to low altitude. However, the student reported significant sink rates and improper control surface response, leading him to decide on an emergency landing in an adjacent field. The student chose a suitable landing site and informed the instructor. During the approach, the pilot realized the airbrakes had been opened. The landing, performed with a light tailwind and a slight overshoot, took place in a field between plots. During the rollout, the left side of the fuselage struck an exposed stone, causing damage to the skin near the front skid and the rear lower section of the fuselage. The pilot sustained no injuries.
The investigation
The investigation examined GPS flight logs, pilot statements, and meteorological data from the Kielce station. The investigation focused on the sequence of events during the tow, the cause of the airbrake deployment, and the pilot's decision-making process during the emergency. The inquiry also reviewed the experience levels of both the student pilot and the tow pilot, as well as the atmospheric conditions present during the flight.
Findings
- The primary cause of the incident was the unintentional opening of the airbrakes (either by the student or via suction during the tow) while flying through turbulent air, which necessitated the field landing.
- The landing was performed as an overshoot in an unprepared field.
- The student pilot had limited experience, with only 31 total flight hours and only two previous solo flights in the SZD 30 Pirat.
- The tow pilot also had limited experience, having obtained towing credentials only in 2017.
- Atmospheric conditions were contributing factors, as meteorological data showed significant wind gusts (up to 10 m/s), indicating highly dynamic thermal activity that contributed to the turbulence encountered during the tow.