What happened
On September 3, 2006, at approximately 15:07 UTC, a Diamond HK36TTC motor glider crashed into the Vesulspitze in the Silvretta Mountains, near Kappl, Austria. The aircraft was performing a private flight from Grenoble, France, to Innsbruck, Austria.
The flight was the final leg of a long journey that had begun several days earlier in Innsbruck, with various stops in Spain and France. On the day of the accident, the pilot had previously stopped in Ampuriabraube and Grenoble. During the final leg toward Innsbruck, the aircraft maintained altitudes between 4,000 and 4,570 meters for a significant period.
As the aircraft approached the Austrian border, the pilot began a descent. Witnesses observed the aircraft performing several maneuvers, including tight turns, while flying through a continuous cloud layer with light rain. During this descent, the aircraft transitioned from visual flight conditions into instrument meteorological conditions (IMC). The left wing of the aircraft struck a rocky ridge at approximately 148 km/h, and the propeller subsequently impacted a rock face at an altitude of roughly 2,860 meters. The pilot sustained fatal injuries in the impact.
The investigation
The investigation examined the flight sequence, the aircraft's technical condition, and the pilot's physiological state. Investigators reconstructed the flight path using eyewitness accounts and local police findings. The investigation also reviewed the weather conditions, noting that the cloud base was approximately 2,800 meters, meaning the aircraft was flying within a cloud layer during its descent.
Technical examination of the Diamond HK36TTC showed no evidence of mechanical failure or maintenance issues that could have contributed to the crash. The aircraft's weight and center of gravity were also believed to have been within limits. The investigation focused heavily on the pilot's decision-making during the descent and the physiological factors present during the long-duration flight.