SZD-51-1 Junior incident during aerotow launch at Birrhard
On June 28, 1986, a SZD-51-1 Junior glider experienced an incident shortly after takeoff from Birrfeld Airfield in Switzerland. The glider, piloted by a woman on a training flight, was being towed eastward when it began to oscillate. The tow cable detached at approximately 1000 meters, leading the glider into a steep descent. The glider completed a full 360-degree turn before impacting the ground at a steep angle. The pilot sustained serious injuries, and the aircraft was destroyed. The investigation confirmed the accident was caused by insufficient airspeed during a turn after release from the tow.
- Aerotow initial climb: The glider departed Birrfeld on an aerotow training flight to the east and initially climbed normally behind the towplane.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.