Colisión en el aire de ASW 19 sobre La Para cerca de Château-d'Oex, Suiza

El 2 de julio de 1999, dos planeadores ASW 19 colisionaron en el aire sobre La Para cerca de Château-d'Oex, Suiza. Ambos pilotos participaban en un evento local de vuelo a vela bajo condiciones meteorológicas favorables. Durante una maniobra de ascenso en térmica, los planeadores perdieron el contacto visual y colisionaron. Ambos pilotos evacuaron de manera segura usando paracaídas y aterrizaron sin lesiones. Los planeadores fueron destruidos al impactar con el suelo, pero no se produjeron daños adicionales ni lesiones.

1. Thermaling climb: During an informal soaring training flight, the HB-3172 was thermaling and climbing near the ridge between Pic Chaussy and La Para after about two hours of independent soaring.
2. Low pilot experience: Both glider pilots were recently licensed with relatively low total and type hours, reducing their experience in close-proximity thermaling.
3. Shared thermal use: HB-1573 joined the same thermal as HB-3172, turning to the right in a good climb below and near the other glider, with both aircraft flying different orbits that could intersect.
4. Loss of mutual visual: After initially sighting each other, the pilots lost visual contact and, following a brief radio position exchange, had no further visual or radio coordination while continuing to circle in the same thermal.
5. Inadequate lookout above/below: The lower pilot primarily looked upward while climbing and the upper pilot, limited by cockpit blind spots and not adjusting his orbit sufficiently, had a restricted view of the glider below.
6. Converging orbits: While HB-3172 had reached its ceiling altitude and HB-1573 continued climbing at about 3 m/s, their differing right-hand orbits gradually converged without either pilot fully aware of their relative positions.
7. Mid-air collision: HB-1573’s left wing struck the left side of HB-3172’s cockpit in a mid-air collision over the north side of La Para, both pilots bailed out by parachute uninjured, and both gliders crashed and were destroyed on the mountainside.