What happened
On July 14, 2018, a Schepp-Hirth Ventus b/16.6 glider, registration OK-5293, was performing a cross-country thermal flight when it crashed into a field approximately 500 meters northeast of Řevničov. The pilot had taken off from Slaný airfield via aero-tow and had been searching for thermal lift. After finding no suitable rising air, the pilot decided to perform a landing in a nearby field.
During the landing pattern, the pilot executed several 360-degree turns to survey the landing area and began discharging water ballast from the wings. While executing the fourth turn of the right-hand circuit, the aircraft experienced a significant loss of airspeed. This led to a wing-low stall and a subsequent impact with the ground. The aircraft first struck the earth with the tip of the right wing, followed by the front right underside of the fuselage, before sliding and rotating approximately 180 degrees. The impact caused extensive damage, including the destruction of the cockpit canopy, the breakage of the tail section, and the loss of the right wing root.
The investigation
The ÚZPLN investigation utilized data from the aircraft's onboard tracker and the pilot's testimony. The investigation confirmed that the pilot was fully qualified with a valid medical certificate and significant flight experience. The aircraft was also found to be airworthy with valid inspections and insurance. Meteorological data indicated that while the weather was suitable for flight, the pilot was managing varying wind conditions, including a westward and northwestward breeze. The investigation examined the flight profile, which showed the aircraft descending from approximately 700 meters to an impact altitude of 517 meters AGL.
Findings
- The primary cause of the accident was incorrect piloting technique, which resulted in a loss of airspeed during the fourth turn of the landing pattern.
- A contributing factor was the negative effect of a tailwind component, which further compromised the aircraft's energy during the low-altitude maneuver.
- The pilot was aware of the wind direction and strength during the approach but was unable to maintain sufficient flying speed to prevent the stall.