Ka 8 B collision with tree during landing near Les Pres Vaillons, Switzerland
On May 28, 1976, an Alexander Schleicher K 8 B glider collided with a tree during a landing attempt near Les Pres Vaillons, Switzerland. The pilot, aiming to complete a 75 km flight to Courtelary, became disoriented and entered a narrow valley. Despite the presence of suitable landing areas earlier in the flight, the pilot continued until a collision occurred. The glider was destroyed, and the pilot sustained injuries. The official report cites insufficient geographical and navigational knowledge as contributing factors.
- Cross-country cruise: After an aerotow departure from Fricktal-Schupfart, the pilot cruised along the Jura ridge toward his 75 km goal at Courtelary.
- Navigation error: Near the Taubenlochschlucht, the pilot misnavigated toward Courtelary by following what he thought was the correct valley, using an inadequately folded 1:200,000 map and then the 1:500,000 ICAO chart.
- Poor map setup: The topographic map was folded so that the Bielersee and the accident area were not visible, forcing reliance on a small-scale ICAO chart and rough valley counting.
- Delayed outlanding decision: Despite being in an area with suitable outlanding fields, the pilot continued toward the presumed goal instead of committing to an outlanding by 500 m AGL as recommended.
- Continued into narrow valley: The pilot flew in low level into the valley between Mont Sujet and the south flank of Chasseral, passing a last suitable pasture near Métairie de Prêles without attempting to land.
- Trapped low in valley: At low height above the terrain, the pilot attempted to turn but, due to the narrow valley and insufficient altitude, rolled out and continued just above the treetops down the descending valley.
- Crash - minor injury: About 1.3 km beyond the pass, the right wingtip struck the top of a fir tree, the glider overturned into a near-vertical crash, destroying the aircraft and injuring the pilot.