Colisión de un SZD-12A con un árbol durante la aproximación a baja altitud cerca del aeródromo de Courtelary

El 9 de julio de 1973, un SZD SZD-12A Mucha 100A experimentó una colisión con un árbol durante una aproximación a baja altitud cerca del aeródromo de Courtelary, Suiza. El piloto, que resultó ileso, intentó aterrizar en un campo tras encontrar corrientes descendentes. A pesar de los esfuerzos por ganar altitud, el planeador chocó contra un árbol y se detuvo en el lecho del río. La aeronave sufrió daños significativos, pero no se reportaron lesiones. El informe final identificó el accidente como resultado de una aproximación a una altitud demasiado baja.

1. Aerotow local soaring: The pilot aerotowed from Courtelary runway 07 and released near the ridge north of Cortébert at about 700 m QFE for a local soaring flight.
2. Weak lift conditions: After release the pilot found no usable lift near the ridge and then only weak 0.5–1 m/s climbs over Courtelary, indicating marginal soaring conditions.
3. Low circuit altitude: The pilot remained in the circuit area over Courtelary at altitudes down to about 250 m QFE and repeatedly flew left-hand turns in final approach instead of committing to a standard landing pattern as required.
4. Encountering strong sink: While turning left over Courtelary and briefly gaining 50–60 m, the glider then encountered descending air of about 3–4 m/s when on a northerly heading.
5. Continued low turns: The pilot continued the left turn through to a southerly heading to try to return to the aerodrome despite the strong sink and already low height.
6. Forced field landing: Realizing he could no longer reach the runway due to continued sink and insufficient altitude, the pilot elected to attempt a landing in a field parallel to the Suze north of the aerodrome and initiated a low-altitude turn onto the field axis.
7. Crash - no injury: During the low-altitude turn toward the field the left wingtip struck a tree on the north bank of the Suze, and the glider crashed into the riverbed and pivoted, sustaining serious damage while the pilot was uninjured.