Collision du Ka 2b avec des arbres lors d'un lancement au treuil à l'aérodrome de Samedan
Le 16 septembre 1964, un planeur Ka 2b s'est écrasé peu après un lancement au treuil à l'aérodrome de Samedan en Suisse. Le pilote, né en 1929, a entamé un vol le long de la crête de Muottas-Muragl mais a heurté les cimes des arbres en raison d'une altitude insuffisante. Le planeur a été gravement endommagé et le pilote a subi des blessures importantes. L'enquête officielle a conclu que le pilote est entré dans une zone de courant descendant turbulent à basse altitude, entraînant la collision.
- Winch launch climb: During the winch launch from Samedan, the Ka 2b climbed too shallowly after liftoff, leading to an unusually high airspeed and reduced winch power.
- Low release altitude: The pilot released from the winch at only about 200–250 m above ground, roughly half the normal height for the prevailing wind conditions.
- Limited winch experience: The pilot had not previously winch-launched the Ka 2b and had very limited and outdated winch-launch experience overall, reducing his familiarity with required climb profile and usable release height.
- Turbulent ridge winds: Moderate southwesterly wind around 15–20 kt at the Muottas-Muragl slope produced hang turbulence and local downdrafts near the treeline.
- Continued to ridge low: Despite recognizing the low release height, the pilot chose not to fly a circuit to land but instead turned toward the Muottas-Muragl slope and continued along the trees at slowly decreasing altitude.
- Sink in lee turbulence: While flying close above the treetops near the Muottas-Muragl railway, the glider entered lee turbulence and downdraft, lost its remaining height margin, and likely sank further as the pilot pulled to arrest the descent.
- Crash - serious injury: The left wing struck several treetops, tearing off about one-third of the wing, and the glider fell roughly 40 m to the ground near the Muragl stream, seriously injuring the pilot and almost completely destroying the aircraft.