What happened
On July 7, 2013, a Standard Cirrus glider, registration OK-2999, was performing a thermal soaring flight originating from Hodkovice airport. Approximately 15 minutes into the flight, the pilot decided to perform a field landing on a meadow approximately 1 km northeast of Kaškovice due to current thermal conditions and insufficient altitude to return to the home aerodrome. The chosen landing site was a slightly sloping meadow located on the leeward side of a hill topped with forest.
During the approach, the pilot maintained an indicated airspeed of 110 km/h and used air brakes to coordinate the descent. At an altitude of approximately 20 m AGL, the aircraft experienced a sudden drop in airspeed of more and more than 40 km/h and a significant loss of lift. While the pilot attempted to react by applying slight forward pressure on the control lever to prevent a stall and subsequent uncontrolled descent, the aircraft struck the ground heavily on its main landing gear.
The investigation
The ÚZPLN investigation examined the flight sequence, meteorological conditions, and the aircraft's technical status. The investigation established that the pilot was fully qualified with a valid medical certificate and that the aircraft was airworthy, having undergone its annual inspection in May 2013. Investigators analyzed the wind conditions, noting that the wind was blowing from the north at 6–8 knots, passing over the forested ridge.
Findings
- The pilot underestimated the potential for airflow changes caused by obstacles (the forest) on the leeward side of the hill.
- The wind passing over the trees likely created mechanical turbulence and rotors.
- The pilot reacted correctly to the sudden loss of airspeed by applying control input to prevent a high-altitude stall.
- Due to the low altitude at the time of the disturbance, the pilot was unable to fully recover the glider's attitude before impact.
- The hard landing resulted in a serious spinal injury to the pilot, though no structural damage was sustained by the Standard Cirrus.
Safety action
No safety recommendations were issued by the ÚZPLN.