What happened
On July 29, 2017, during the FAI World Glider Aerobatic Championships at Toruń (EPTO), a pilot was completing the first competition task. After finishing the aerobatic program, the pilot directed the SZD-59 Acro, registration SP-3765, toward a landing on runway 10 with a tailwind.
As the pilot performed the fourth turn of the landing pattern at an altitude of approximately 60 meters, the aircraft entered an area of rotors caused by the leeward edge of a nearby forest. This turbulence triggered a sudden and violent increase in the vertical sink rate. The pilot attempted to react by pulling back on the control stick, but the low altitude prevented the recovery of control. The glider struck the ground heavily, likely in a tail-first or two-point configuration. The impact caused the rudder to separate from the vertical stabilizer and resulted in the main landing gear collapsing. The aircraft slid approximately 200 meters before coming to a stop. Despite the significant damage to the airframe, the pilot escaped the cockpit without injury.
The investigation
The PKBWL examined the flight data recorded by the PHMD electronic height measuring device, which confirmed the aircraft's altitude and speed during the maneuvers. The investigation reviewed the pilot's training history, noting that while experienced in advanced aerobatics, this was the pilot's first flight in a single-seat glider at a World Championship level. The investigators also analyzed the meteorological conditions and the physical impact on the airframe, noting that the heavy impact caused extensive damage to the fuselage, tail section, and canopy frame.
Findings
- The primary cause of the accident was the execution of the fourth turn at an insufficient altitude within an area of rotor turbulence.
- The pilot lost control of the aircraft due to a sudden, sharp increase in the vertical sink rate caused by the atmospheric disturbances.
- High psychological stress related to competing in a World Championship event acted as a contributing factor, potentially affecting the pilot's decision-making and concentration during the critical landing phase.
- The presence of rotors on the leeward side of the forest and the thermal variations near the concrete runway contributed to the unstable air conditions.