What happened
On May 21, 2017, a pilot participating in the 9th FAI Women's Gliding World Championships was conducting a competitive flight in the Standard Class. After utilizing the last available thermal approximately 19 km south of Zbraslavice airfield (LKZB), the pilot began a glide descent from 1,200 m AMSL. As thermal activity had significantly weakened and no further lift could be found, the pilot realized there was insufficient altitude to safely reach the airfield.
At approximately 15:34 UTC, the pilot decided to perform a landing in a field near the village of Bělá. The approach was conducted against the wind, passing over high-voltage power lines and a dense line of trees. During the final stages of the maneuver, the pilot found the available landing area to be too short. Despite the aircraft being near stall speed, the pilot attempted to accelerate the descent by partially deploying spoilers. This action caused a sharp increase in the vertical descent rate, which the pilot could not adequately counteract. The LS-8a glider struck the ground with its main landing gear, nose wheel, and the tip of the right wing.
Following the initial impact, the aircraft bounced twice and traveled approximately 18 meters before coming to a stop, eventually rotating 90 degrees to the left.
The investigation
The ÚZPLN examined the flight data recorder, the aircraft's structural condition, and meteorological reports from the ČHMÚ. The investigation focused on the pilot's decision-making process regarding the glide descent, the flight path over obstacles, and the aerodynamic effects of the control inputs made during the final approach. The investigation also noted the ground conditions, observing that the soil was wet, suggesting that water ballast had likely been jettisoned shortly before the landing.
Findings
- The pilot made a late decision to terminate the flight and land in the field rather than attempting to reach the airfield.
- The landing area was unsuitable for the maneuver due to its short length and the presence of significant obstacles.
- The pilot failed to jettison the water ballast in a timely manner.
- The deployment of spoilers caused an excessive increase in the vertical descent rate that could not be recovered.
- The aircraft sustained serious structural damage to the forward and aft fuselage, as well as the right wing.
- The pilot was uninjured but was taken to the hospital for observation.