Colisión de un ASK 23 con un coche durante el aterrizaje en el aeródromo de Birrfeld

El 24 de abril de 1988, un Alexander Schleicher ASK 23 intentó un aterrizaje en el aeródromo de Birrfeld en Suiza. El piloto, tras un vuelo de entrenamiento, encontró dificultades durante la aproximación debido a los fuertes vientos y la baja altitud. Cuando el planeador se acercaba al aeródromo, colisionó con un coche en una carretera cercana, hiriendo a un pasajero. El planeador sufrió daños pero aterrizó de manera segura. El incidente se atribuyó a que el planeador descendió por debajo de la altura mínima de seguridad sobre la carretera.

1. Aerotow local soaring: After four earlier winch launches with an instructor, the pilot aerotowed the ASK 23 from Birrfeld and spent about an hour soaring on the Chestenberg ridge in moderate to strong northeasterly wind.
2. Left ridge too low: In a headwind (bise) situation, the pilot departed the Chestenberg area toward Birrfeld at only about 300 m above airfield level, too low for a standard arrival.
3. Headwind sink on return: On the return toward Birrfeld the glider encountered sink and, with increased airspeed needed to penetrate the headwind, lost further height, preventing entry into the normal landing circuit.
4. Abandoned normal circuit: Unable to reach the designated circuit area, the pilot skipped the usual pattern and aimed directly for the prescribed right base leg at low height.
5. Did not outland: Despite being in a critical low-height situation over flat open terrain between the railway and the airfield, the pilot chose not to perform a low-risk outlanding and instead continued toward the runway.
6. Very low final approach: Following the railway north and then turning back in a shallow left base, the glider approached the airfield at an estimated 10–20 m above ground with an unsteady flight path, below the required safety margin over the nearby road.
7. Crash - serious injury: About 20 m before the slightly elevated road along the airfield boundary, the pilot noticed a red car too late and the glider’s nose and main wheel struck the car roof, seriously injuring the front passenger, after which the glider bounced and then landed, sustaining damage.