What happened
On July 4, 2008, a DG-800S glider, registration HB-3309, was participating in a regional gliding competition near Samedan, Switzerland. Following a standard winch launch, the aircraft reached an altitude of 2,130 meters. While flying near the Chantaluf slope, the pilot executed a right-hand turn at a low altitude. During this maneuver, the aircraft entered a spin and descended into the terrain. The impact occurred in a wooded area, where the aircraft struck the ground in a steep, inverted position. The pilot sustained fatal injuries upon impact, and the aircraft was destroyed.
The investigation
Investigators examined the aircraft's flight data logs and wreckage to reconstruct the flight path. The investigation focused on the aircraft's weight and balance, as the pilot had manually added water ballast to the wing and fuselage tanks prior to the flight. Analysis of the wreckage revealed that the flaperon linkage was positioned in a non-standard notch between the '0' and '-5' settings, a modification previously installed by a former owner. This intermediate position was not documented in the aircraft's flight manual. The investigation also reviewed meteorological conditions, noting turbulent, gusty northeast winds at the time of the accident.
Findings
- The primary cause of the accident was a collision with the terrain following a loss of control during a low-altitude turn.
- The pilot utilized a flight tactic that was inappropriate for the prevailing atmospheric conditions.
- The aircraft was operating with an aft center of gravity, which increases the risk of entering a spin.
- The flaperon position may have been incorrectly set due to the undocumented intermediate notch.
- The presence of turbulent conditions required a higher speed reserve, which was not maintained during the maneuver.