What happened
On the afternoon of May 3, 1997, a two-seat MDM-1 Fox glider, registration HB-3195, departed from Sion airport for a local training flight. The pilot, accompanied by a passenger, released from the towplane near Anzère at an altitude of approximately 2,000 meters. During the flight, the glider was observed performing wide-diameter spirals and maneuvers along the slope in coordination with another glider.
At approximately 14:20 local time, while flying in a straight, level path near the Anzère-Pas-de-Maimbré cable car, the aircraft suddenly stalled and entered a very pronounced, high-speed spin with a near-vertical nose position. The aircraft struck a large rock formation before bouncing onto a snow-covered ledge. The impact was so violent that both the pilot and the passenger sustained fatal injuries, and the aircraft was destroyed.
The investigation
Investigators examined the wreckage and found no evidence of mechanical failure; control linkages, cables, and aileron connections were all intact. The aircraft was found to be slightly overweight, with a takeoff mass of 531.1 kg, exceeding the maximum authorized mass of 525 kg by approximately 6 kg. The center of gravity was positioned toward the forward limit.
Medical examinations of the occupants revealed no evidence of pre-existing medical conditions, nor any traces of alcohol or drugs. Meteorological data indicated stable high-pressure conditions with light winds, though thermal turbulence was present. Witnesses noted that the glider had been attempting to gain altitude by flying back and forth along the valley floor without success prior to the accident.
Findings
- The aircraft was operating in a state of slight overload.
- The pilot was likely attempting to gain altitude in an area known for thermals but was unable to find sufficient lift.
- In an effort to climb, the pilot likely increased the pitch of the aircraft while flying in a straight line, inadvertently approaching the stall warning speed.
- The stall occurred during straight flight, leading to a spin at an altitude too low to allow for recovery.