What happened
On February 26, 2000, a Piper PA-28-R201, registration F-GOMP, was conducting a VFR flight from Sion, Switzerland, toward Annemasse, France. After departing Sion, the pilot navigated through the Val de Nendaz, passing the Cleuson dam at approximately 8,000 feet.
Upon realizing that the surrounding ridges would prevent passage into the Val de Bagnes, the pilot attempted a 360-degree right-hand turn within the valley floor to gain altitude. During this maneuver, the right wingtip struck a thin rocky outcrop protruding from a steep, snow-covered slope. The aircraft slid into a stop on its belly at an altitude of approximately 2,750 meters on the northern slope of Grand Mont Calme. Both the pilot and the passenger sustained serious injuries, particularly to the face, and were rescued by helicopter.
The investigation
The investigation established that the aircraft was properly maintained with a valid certificate of airworthiness, and the weight and center of gravity were within prescribed limits. Sufficient fuel was on board for the intended flight. Technical examination of the engine parameters showed no evidence of power loss during the critical phase of flight, contradicting the pilot's initial suggestion.
While both occupants were wearing seatbelts, they had not utilized the shoulder straps. Meteorological conditions at the time were clear with visibility exceeding 10 km, though winds at higher altitudes were blowing from the northwest.
Findings
- The pilot was executing maneuvers at a low altitude within an alpine valley.
- The aircraft was subject to downdrafts caused by northwest winds hitting the terrain, which likely surprised the pilot during the turn.
- Flying at low altitudes in alpine terrain presents significant challenges, including the lack of a visible horizon and the difficulty of accurately estimating vertical and horizontal distances.
- The failure to use shoulder harnesses likely contributed to the severity of the facial injuries sustained by the occupants.