Incidente del SZD-51-1 Junior durante el remolque en Birrhard

El 28 de junio de 1986, un planeador SZD-51-1 Junior experimentó un incidente poco después del despegue del aeródromo de Birrfeld en Suiza. El planeador, pilotado por una mujer en un vuelo de entrenamiento, estaba siendo remolcado hacia el este cuando comenzó a oscilar. El cable de remolque se desprendió a aproximadamente 1000 metros, llevando al planeador a un descenso pronunciado. El planeador completó un giro de 360 grados antes de impactar contra el suelo en un ángulo pronunciado. La piloto sufrió heridas graves y la aeronave fue destruida. La investigación confirmó que el accidente fue causado por una velocidad insuficiente durante un giro después de la liberación del remolque.

1. Aerotow initial climb: The glider departed Birrfeld on an aerotow training flight to the east and initially climbed normally behind the towplane.
2. Glider begins pendulum: Shortly after takeoff the glider began to oscillate in tow, at times flying above and then well below the normal tow position, forcing the tug pilot to correct his own attitude.
3. Short tow cable: A relatively short 35 m tow cable was used instead of the recommended 40–60 m, reducing positional margin and making accurate tow position more demanding for the inexperienced pilot.
4. Low experience, turbulence: The pilot had limited glider experience and was flying in light Bise turbulence, conditions that likely contributed to the difficulty in maintaining a stable tow position.
5. Pilot releases tow: Unable to stop the oscillations, the pilot released from tow via the nose hook at about 1000 m above ground and initiated a right turn.
6. Low-speed turn back: While attempting a turn back toward the airfield, the glider entered a right turn of about 120° into the tailwind and its airspeed dropped below minimum, leading to an increasingly steep descent and a full 360° turn.
7. Crash - serious injury: The glider impacted the ground near Birrhard at an estimated 60° nose-down attitude, destroying the aircraft and seriously injuring the pilot.