What happened
On July 6, 2016, a DG-800 S glider, registration HB-3358, departed from Saanen (LSGK) via aero-tow for a local flight in the Saanenland/Simmental region. The pilot intended to complete a flight long enough to reach a milestone of 1,000 total flying hours. After a period of soaring through the mountains, the aircraft was flying near the Mittaghore peak.
Approximately 86 seconds before the impact, the pilot began recording a video using his mobile phone. During this time, he operated the aircraft using only his left hand. The video footage captured the approach toward the rising terrain, but also showed the pilot panning the camera between the instruments and the landscape. At 13:33:49, the right wing of the DG-800 S struck the ridge. The impact caused the aircraft to roll and rotate violently, eventually striking the eastern flank of the mountain and sliding 140 meters downslope. The pilot sustained fatal injuries.
The investigation
SUST examined the wreckage, flight data from the onboard navigation device, and the pilot's mobile phone video. The investigation established that the pilot's seating position was relatively low, which, combined with the instrument panel, obstructed his view of the terrain directly ahead and below.
Analysis of the flight data showed that the airspeed had dropped to 80 km/h shortly before the collision, leaving no safety margin for the terrain. The investigation also reviewed medical records, finding no evidence of an acute health crisis that would have incapacitated the pilot, noting that his known treatment for Type 2 diabetes was managed with medication and did not present an immediate risk to flight safety during this flight.
Findings
- The primary cause of the accident was the collision of the right wing with a mountain ridge.
- The pilot was distracted by filming with his mobile phone, which diverted his attention from active terrain monitoring.
- The aircraft was flying at an insufficient airspeed of 80 km/h for the proximity to the terrain, eliminating necessary safety margins.
- The pilot's low seating position and the presence of the instrument panel created significant blind spots regarding the approaching ridge.
- The pilot was flying the aircraft with one hand while operating the recording device with the other.