Colisión en el aire entre Karpf Baby y Grunau Baby sobre Weiningen durante un vuelo de entrenamiento

El 12 de abril de 1961, ocurrió una colisión en el aire entre un Karpf-Flugzeugbau Karpf Baby y un Edmund Schneider Grunau Baby cerca de Weiningen, Suiza. Ambas aeronaves estaban realizando vuelos de entrenamiento como parte de un campamento de vuelo a vela organizado por el Segelfluggruppe Winterthur. La colisión ocurrió a aproximadamente 750 metros de altitud mientras ambos planeadores estaban en la misma área térmica. El piloto del Karpf Baby logró salvarse en paracaídas, pero el piloto del Grunau Baby resultó fatalmente herido. La investigación oficial atribuyó la colisión principalmente a una vigilancia insuficiente del espacio aéreo por parte del piloto del Grunau Baby.

1. Aerotow — thermaling: After an aerotow launch at 12:58 and release around 13:02, the HB-497 pilot began thermaling and rapidly gaining height in the established lift area north of Frauenfeld.
2. Shared thermal use: HB-497 entered and circled in the same thermal column where HB-512 was already circling above with the same left-hand turn direction, creating vertical proximity in the same air mass.
3. Limited experience & workload: As a relatively low-time student pilot performing a required thermaling task, the HB-497 pilot was likely highly focused on climbing performance and instrument indications, increasing susceptibility to neglecting lookout.
4. Inadequate lookout above: While climbing in the thermal, the HB-497 pilot began or continued circling without adequately monitoring the airspace above, failing to detect the higher HB-512 despite converging vertically.
5. Continued climb under HB-512: HB-497 continued to climb in the same left-hand circle beneath HB-512, with the vertical separation steadily decreasing as observed by a witness, and with the HB-512 pilot no longer keeping HB-497 continuously in sight.
6. Converging flight paths: As HB-497 rose and HB-512, likely slipping outward and no longer climbing, both gliders’ circular paths converged laterally and vertically until HB-497’s right wing leading edge appeared just below HB-512’s right wing, leaving no time to avoid impact.
7. Crash - fatal: HB-497’s forward fuselage struck the trailing edge of HB-512’s right wing, tearing it off; HB-512 entered an uncontrolled descent from which the pilot bailed out safely, while the severely damaged HB-497 went into a steep dive and crashed, fatally injuring its pilot.