What happened
On July 6, 2018, a student pilot and an instructor were conducting a training flight at Vlašim Airport (LKVL) in a L-13 Blanik, registration OK-6815. The flight was part of a check-ride procedure intended to certify the student for solo flight.
During the final approach to runway 31, the pilot maintained an indicated airspeed of approximately 90 km/le. While performing the flare, the pilot inadvertently pulled both the control stick and the air brake lever simultaneously. This sudden deployment of the air brakes caused the glider to lose lift and drop abruptly.
At a height of approximately 20 meters before the runway threshold, the glider's landing gear struck tall wheat crops located in a field adjacent to the runway. The impact caused the left side of the landing gear to be torn from its mount and resulted in a hard landing on the runway surface. There were no injuries to the crew.
The investigation
The ÚZPLN investigation focused on the sequence of events during the landing maneuver and the mechanical state of the aircraft. Investigators examined the pilot's actions during the flare and the instructor's ability to intervene. The investigation also included a technical inspection of the L-13 Blanik by a maintenance organization to assess the extent of the structural damage caused by the impact with the crops and the subsequent hard landing.
Findings
- The pilot's simultaneous movement of the control stick and the air brake lever caused the unintended deployment of the air brakes.
- The deployment of the brakes led to an immediate loss of altitude, causing the glider to undershoot the runway.
- The aircraft was flying too low over the obstacle (the wheat field) at the moment the brakes were deployed, leaving insufficient altitude for recovery.
- The instructor was unable to prevent the hard landing due to the sudden and unexpected nature of the maneuver.
- The damage to the aircraft, including the failure of the left landing gear mount and damage to both elevators, was a direct result of the impact with the crops and the hard landing.