Ka 4 Rhönlerche II Außenlandung in Kiesgrube nahe dem Flugplatz Winterthur

Am 5. Juli 1964 erlebte eine Ka 4 Rhönlerche II eine Außenlandung nahe dem Flugplatz Winterthur in der Schweiz. Der Flug war Teil einer Übung der Segelfluggruppe Winterthur. Während des Landeanflugs schätzte der Flugschüler die Höhe falsch ein und geriet in Abwinde, was zu einer Außenlandung in einer nahegelegenen Kiesgrube führte. Das Flugzeug erlitt Schäden am Rumpf und an den Flügelverbindungen, aber der Pilot blieb unverletzt. Der Vorfall ereignete sich während der ersten Nutzung des neu eröffneten Flugplatzes durch die Gruppe.

1. Winch launch circuit: The student pilot launched by winch from Winterthur-Hegmatten and flew a standard training circuit, reaching about 260 m above the field before positioning for landing.
2. Low experience level: The student had limited overall gliding experience and this was only his second flight from the newly opened Winterthur-Hegmatten airfield, reducing his familiarity with its circuit and height cues.
3. Low circuit altitude: Before starting the approach he descended in turns to roughly 100 m above the field, which was at the lower limit for executing a normal landing pattern.
4. Altitude misjudged: Believing he still had sufficient height, the student turned onto a normal-length final approach similar to the preceding dual check flight, despite being lower than appropriate.
5. Downdraft on final: While on final over the water surface of the gravel pit in line with runway 05, the glider encountered sinking air that further reduced its glide path.
6. Committed to outlanding: Recognizing he could no longer reach the airfield, the pilot continued just above the water surface, which lay about 4 m below field level, and elected to land in the gravel pit area.
7. Outlanding - damage: The glider touched down on a gravel bank and then collided head-on with the edge of the pit, damaging the fuselage nose and wing attachments while the pilot remained uninjured.