Crash d'un Ka 6 près de Hausen am Albis après une rencontre avec des turbulences
Le 9 juin 1964, un planeur Alexander Schleicher Ka 6 BR s'est écrasé près de Hausen am Albis, en Suisse. Le pilote, un homme de 39 ans, effectuait un vol de distance lorsque le planeur a rencontré des turbulences près de la crête de l'Albiskette. L'appareil a subi une perte de vitesse et d'altitude, entraînant un crash d'environ 30 mètres. Le pilote a subi de graves blessures, dont des fractures, mais il n'y a eu aucun décès. Le planeur a été gravement endommagé, avec des coûts de réparation estimés entre 70% et 80% de sa valeur.
- Cross-country soaring: After launching by aerotow from Hausen am Albis at 1230, the pilot continued a cross-country soaring flight in the local area when the expected weather did not materialize.
- Low ridge clearance: On the return leg from Sihlbrugg, the pilot flew along the Albiskamm with only about 50 m clearance above the ridge, providing little height margin in case of sink or turbulence.
- Lee-side turbulence: The glider crossed from the windward to the lee side of the Albis ridge into an area of moderate Bise-induced lee turbulence behind tall trees.
- Airspeed misjudged: With a tailwind in the lee, the pilot likely judged his speed by groundspeed and believed he was flying at a normal speed, although true airspeed was probably too low.
- Turn initiated low: Realizing too late that his height was insufficient to continue, the pilot initiated a relatively abrupt turn in the turbulent lee flow at low altitude.
- Stall and nose drop: The combination of low true airspeed, turbulence, and abrupt control input led to an aerodynamic stall with the glider losing speed and pitching nose-down from about 30–40 m AGL.
- Crash - serious injury: From insufficient height to recover, the glider impacted the ground almost straight ahead in a forest clearing, heavily damaging the aircraft and seriously injuring the pilot.