Accident Details
On 21 May 1988, a Schleicher Ka 6 glider, registration HB-755, operated by the Aéro-Club des Montagnes neuchâteloises, was destroyed in an accident at Les Hauts-Geneveys, at a location known as Tête de Ran. The pilot, a Swiss national born in 1961, held a valid glider pilot license with a total of 97 hours and 56 minutes of flight time, including 20 hours and 42 minutes on the Ka 6 type. The pilot had not flown in the preceding 90 days. The glider was properly maintained and within weight and balance limits.
Flight Sequence
The pilot departed from La Chaux-de-Fonds airport (Les Eplatures) at 1424 hours local time for a training flight. A tow plane released the glider at 1700 m above mean sea level near Pouillerel. After about 15 minutes of soaring in moderate lift, the pilot flew southeast toward Tête de Ran, where other gliders were operating. Rapid altitude loss led him to decide on an off-field landing in a nearby valley he had observed the previous week.
The pilot initiated a left-hand approach pattern with a downwind leg parallel to the western ridge of the valley. While on base leg, perpendicular to the wooded ridge bordering the chosen field, he encountered strong downdrafts. The glider's left wing struck a fir tree as it passed over the treeline, and the aircraft crashed into the slope at the base of the trees.
Meteorological Conditions
Weather at the accident site around 1430-1500 local time: wind from northeast to east at 10-15 knots, visibility 10-15 km, cumulus clouds at 1600-1700 m, temperature 6-7°C, dew point 0°C, moderate to strong turbulence near the ground. The cloud base left about 400 m clearance above the highest terrain, but conditions varied rapidly along the glider's path.
Findings
The pilot was qualified for the flight, and no health issues were identified. The glider was airworthy and properly maintained. The accident was attributed to a missed off-field landing. Contributing factors included the pilot's modest experience in off-field landings (no such landings in the previous 90 days), an inadequate choice of landing field, and unfavorable weather conditions that created strong downdrafts near the ridge.