What happened
On July 25, 2018, a G 102 Astir CS glider, registration OK-9916, was performing a landing at Soběslav airport (LKSO) when it veered off the runway. The pilot had been conducting a thermal flight and returned to the airfield following weather changes.
During the final approach to runway 36, the pilot was managing a northwest wind of approximately 4 m/s. While attempting to land, the pilot was unable to sufficiently compensate for the crosswind component, causing the aircraft to drift toward the right edge of the runway. As the glider decelerated, the right wingtip caught in tall grass located adjacent to the runway. This contact induced a sudden rotation of the aircraft by approximately 90 degrees. During this rotation, the tail section of the fuselage struck the ground, resulting in structural damage. The pilot was uninjured.
The investigation
The ÚZPL to determine the cause of the accident examined the pilot's statements, local meteorological conditions, and the physical damage to the aircraft. The investigation confirmed that the pilot was fully qualified and the aircraft was airworthy, with its annual inspection having been completed earlier that year. Investigators analyzed the sequence of the landing roll, noting that the pilot's focus was interrupted by the suddenness of the wing catching the vegetation, which prevented an immediate corrective rudder input to mitigate the rotation.
Findings
- The aircraft drifted to the right edge of the runway due to insufficient compensation for the northwest crosswind.
- The right wing caught in tall grass, creating a torque that rotated the glider 90 degrees.
- The impact of the tail section against the ground caused damage to the horizontal stabilizer attachment pins, cracks in the stabilizer mounting, and damage to the rudder.
- The transition part of the fuselage at the left wing root was torn away.
- The pilot's reaction to the sudden rotation was delayed due to the unexpected nature of the event.