What happened
On August 10, 2014, an AS-K13 glider, registration OK-606 and 66, was engaged in a soaring flight originating from Havlíčkův Brod (LKHB). After separating from a tow plane at approximately 1,100 m altitude, the pilot attempted to locate thermal currents. Due to a southeast wind, the aircraft was drifted back toward the airfield. Seeking to avoid flying against the wind upon a potential return, the pilot flew further southeast, but failed to find continuous rising air.
As the aircraft lost altitude, the pilot identified a mown field near the village of Termesivy as a potential landing site. However, the decision to land in the terrain was made at a critically low altitude of approximately 150 m AGL. During the approach, the pilot performed a 360-degree turn at roughly 100 m AGL. At approximately 40 m AGL, the pilot identified obstacles, including high-voltage power lines and a sloping terrain, and executed a 180-degree turn to land upwind of the slope. During this maneuver, the left wing of the glider struck the ground, causing the aircraft to skid approximately 10 meters. The impact resulted in damage to the fuselage structure and the horizontal stabilizer.
The investigation
The ÚZPLN investigation examined flight recorder data, meteorological reports, and the pilot's statements. The investigation focused on the pilot's flight path, the timing of the decision to land in the terrain, and the execution of the final landing maneuvers. The investigation also reviewed the aircraft's maintenance history, noting that the glider had undergone its annual inspection in May 2014 and was deemed airworthy.
Findings
- The pilot was fully qualified and medically certified for flight.
- The pilot incorrectly chose to fly into an area of the airfield airspace where a return to the home aerodrome was not possible given the wind conditions and declining thermal activity.
- The pilot failed to select a suitable landing site while still at a safe altitude (500 m AGL) and instead waited until a critical altitude of 150 m AGL.
- The late decision to land in the terrain prevented the pilot from performing a proper reconnaissance of the landing area.
- The final landing maneuver was poorly executed, involving multiple turns at low altitude, which ultimately led to the left wing striking the terrain.