What happened
On July 3, 2018, a pilot was conducting a local thermal flight at Benešov airport (LKBE). After more than two hours of soaring, the pilot initiated a return to the airfield, planning to land on runway 27. During the final approach, the VSO 10C Gradient, registration OK-1524, encountered increased sinking air.
As the pilot continued the descent, the left wing of the glider struck a patch of tall rape crops located just east of the runway threshold. The impact pulled the aircraft toward the ground, causing it to rotate around its vertical axis. The nose of the glider then struck the ground, and the aircraft performed a partial roll over the right wingtip. The glider eventually came to rest on the runway, approximately 40 meters west of the threshold, after spinning roughly 27 of degrees.
The investigation
The ÚZPLN investigation examined the flight sequence, the meteorological conditions, and the aircraft's structural integrity. The investigation established that the pilot was qualified and the aircraft had a valid airworthiness certificate. Meteorological data indicated clear to scattered clouds and stable conditions, though the pilot encountered a localized area of increased sinking air during the approach.
Physical examination of the VSO 10C Gradient revealed significant structural damage, including broken wingtips, a destroyed nose section, and damage to the tail assembly and rudder. The investigation also noted that the pilot's reaction to the loss of altitude was a critical factor in the sequence of events.
Findings
- The glider entered a downdraft during the final approach.
- The pilot failed to take appropriate corrective action to manage the increased sinking rate.
- The pilot's improper approach calculation and inadequate response to the sinking air led to the aircraft striking the crop vegetation.
- The contact with the crops caused a loss of control, leading to the subsequent ground impact and rotation.