Collision d'un Ka 6 avec un arbre lors d'un atterrissage en campagne près de Wellhausen, Suisse

Le 7 juin 1970, un Ka 6 CR est entré en collision avec un arbre lors d'une tentative d'atterrissage en campagne près de Wellhausen, Suisse. Le pilote, participant à une compétition régionale de vol à voile, a été contraint de se poser en dehors de l'aérodrome en raison d'une altitude insuffisante. En tentant de se poser sur un champ approprié, le pilote a mal jugé l'approche et a percuté un arbre, entraînant le crash du planeur depuis une faible hauteur. Le pilote a subi de graves blessures et l'appareil a été fortement endommagé. Le rapport officiel a conclu que la décision tardive du pilote de se poser a contribué à l'incident.

1. Cross-country thermaling: During a competition cross-country flight after aerotow from Schaffhausen, the pilot progressed around the task while struggling with weak and intermittent thermals.
2. Insufficient lift en route: On the leg after Amlikon, the pilot was unable to find further usable lift, lost height, and was forced to plan an outlanding near Wellhausen.
3. Late outlanding decision: The pilot delayed the decision to outland until about 300 m above ground over unfamiliar terrain, leaving little height for proper field reconnaissance and circuit planning.
4. Altitude misjudgment: Using QFE set to the higher-elevation departure airfield, the pilot likely misjudged his true height above the lower outlanding field and believed he had more height available than he did.
5. Long, high final approach: He selected a mown field near the road overpass, flew a left-hand circuit, and only after the final 90° turn realized his approach was too long and high, then used full airbrakes and a sideslip to lose height.
6. Last-moment field change: When he saw he would overfly his intended touchdown point, he retracted the airbrakes, pulled up using excess speed, and turned about 90° left to divert to another nearby field, attempting to pass between light poles and over a small tree.
7. Crash - serious injury: During the low-altitude diversion turn the glider struck the tree and crashed from a low height, seriously injuring the pilot and heavily damaging the aircraft.