Collision du Neukom Elfe MN avec un arbre lors d'un atterrissage en campagne près de Baar, Suisse

Le 17 mai 1964, un Neukom Elfe MN a heurté un arbre lors d'une tentative d'atterrissage en campagne entre Baar et Kappel, en Suisse. Le pilote, participant à une compétition nationale de vol à voile, a initié un atterrissage d'urgence après avoir rencontré des difficultés. Pendant l'atterrissage, le frein parachute a échoué, entraînant une approche à grande vitesse et la collision subséquente avec un arbre. Le pilote n'a pas été blessé, mais le planeur a subi des dommages importants. L'enquête a identifié la défaillance de l'attache du frein parachute comme un facteur clé de l'incident.

1. Cross-country thermaling: During a competition cross-country flight after aerotow departure from Hausen am Albis, the pilot flew for an extended period in weak thermals in the Sihlbrugg–Menzingen area.
2. Forced outlanding decision: Around 1400, after insufficient climb in weak thermals, the pilot decided he had to perform an outlanding between Baar and Kappel.
3. Short, tree-lined field: The selected outlanding field was short and surrounded by scattered trees, making it suitable only for a steep approach using the braking parachute.
4. Defective chute attachment: The braking parachute’s cable loop was improperly secured with inadequate clamps, predisposing the parachute attachment to failure under load.
5. Parachute attachment fails: On the first steep approach the pilot deployed the braking parachute, but it provided no braking effect because the attachment tore out, leaving the glider fast and unable to land in the short field.
6. Multiple high-speed re-approaches: Believing initially that the parachute had not fully opened, the pilot overflew the field at high speed, then, after noticing from the shadow that the chute was gone, attempted a second and then a third approach, each time still too fast for the confined area.
7. Outlanding - damage: On the third approach the pilot could no longer clear the last trees and deliberately flew the glider at minimum speed into a tree crown, remaining uninjured while the aircraft was heavily damaged.