Colisión en el aire entre Ka 4 Rhönlerche II y Grunau Baby II cerca de Siblingen, Suiza

El 1 de abril de 1961, ocurrió una colisión en el aire entre un Alexander Schleicher Ka 4 Rhönlerche II y un Edmund Schneider Grunau Baby II cerca de Siblingen, Suiza. Ambos planeadores volaban en condiciones de ascenso por ladera cuando el Rhönlerche II colisionó con el Grunau Baby II, resultando en daños significativos a ambas aeronaves. A pesar de la colisión, ambos pilotos pudieron aterrizar de manera segura sin lesiones. La investigación concluyó que las acciones del piloto del Rhönlerche II contribuyeron a la colisión al perder de vista al Grunau Baby II durante un giro a la derecha.

1. Ridge soaring flight: After aerotow launches from Schaffhausen-Neunkirch, the Rhönlerche HB-669 was ridge soaring along the Siblinger Schlossranden behind and below the Grunau Baby HB-170 in smooth hang lift.
2. Close trail position: As both gliders flew south toward the Randenturm at about 1100 m MSL, the Rhönlerche pilot allowed his aircraft to close to roughly 50 m behind and 20–30 m below the Grunau Baby, a small separation given his limited experience.
3. Right turn by lead: Near the Randenturm, the Grunau Baby, slightly left and above, initiated a right turn, contrary to the Rhönlerche pilot’s expectation of a left turn at the end of the ridge.
4. Follower mirrors turn: The Rhönlerche pilot immediately initiated a right turn as well, from a position slightly right-behind and below the Grunau Baby, and in doing so lost visual contact with the other glider.
5. Converging flight paths: While the Rhönlerche pilot had the Grunau Baby out of sight, the two gliders’ right turns caused their flight paths to converge laterally, rapidly reducing the remaining separation.
6. Late evasive maneuver: Both pilots suddenly reacquired sight of the other aircraft only moments before impact, and although the Rhönlerche pilot steepened his bank and pushed down, the collision could no longer be avoided.
7. Mid-air collision: The left wingtip of the Rhönlerche penetrated the nose of the Grunau Baby, causing serious structural damage to both gliders, but both pilots maintained control and landed safely without injury, one returning to Schaffhausen and the other outlanding near Hinterranden.