What happened
On June 6, 2005, a pilot was conducting a training flight at the EPLS aerodrome to prepare for the European Glider Championships. The weather conditions were favorable, with winds from 250º-280º at speeds of 20-30 km/h. The pilot positioned the SZD-56-2 Diana 2 glider on the edge of a mown strip, aligned with the wind. The glider was configured with 150 liters of water ballast in the wings and 5.5 liters in the tail.
A Jak-12M aircraft was used for the aero-tow, utilizing a 60-meter towline to minimize propeller wash effects on the glider's lateral stability. During the initial takeoff roll on runway 26, the tow aircraft pulled the glider approximately 20 meters forward to clear nearby parked gliders. This maneuver left only about 40 meters of short-mown grass ahead of the aircraft.
As the glider reached a speed of approximately 40 km/h, the pilot retracted the air brakes and began adjusting the flaps from 5º to 21º. During this configuration change, the left wing dipped and struck a patch of taller grass. The pilot attempted to correct the roll using ailerons, but the glider veered significantly off course—witnesses estimated a deviation of over 20º. The aircraft began traversing on its main landing gear with the tailwheel lifted. The pilot eventually released the towline, but the momentum caused the glider to execute a violent ground loop around the left wing, resulting in a broken tail and leaving the aircraft facing 180º from its original takeoff heading.
The investigation
The PKBWL investigation examined the takeoff sequence, the ground conditions, and the pilot's actions during the configuration change. The investigation focused on the interaction between the glider's wing and the terrain, as well as the timing of the towline release.
Findings
- The primary cause of the accident was the delayed release of the towline after the wing had already struck the grass.
- A contributing factor was the excessive height of the grass in the takeoff path.
- It was noted that while experienced pilots suggest a flap setting of +14º for takeoff in this model, the cramped cockpit space of the SZD-56-2 Diana 2 makes changing flap settings during the takeoff roll difficult and not recommended.