SZD-9 Bocian crash during winch launch at Samedan airfield resulting in two fatalities
On July 4, 1971, an SZD-9 Bocian crashed during a winch launch at Samedan airfield in Switzerland. The two-seater glider, piloted by a flight instructor and a trainee, experienced a steep and unstable launch. The winch cable released at an altitude of 70 to 100 meters, leading to a stall and a subsequent spin. The aircraft impacted the runway, resulting in the destruction of the glider and the immediate fatalities of both occupants. The investigation confirmed the cause as a combination of insufficient speed, steep launch angle, and inadequate control input after cable release.
- Winch launch climb: The Bocian HB-648 began a winch launch from the grass runway at Samedan with the trainee in front and instructor in the rear, initial ground roll and liftoff appearing normal.
- Excessively steep climb: At about 10–15 m above ground the glider was pitched into a very steep climb, causing a noticeable reduction in airspeed and oscillations about the longitudinal and vertical axes.
- Limited winch experience: Both pilots had very little recent winch-launch experience, with the instructor’s last winch launch eight years earlier and the trainee’s only winch launches two years prior on a different type.
- Cable auto-release: Around 70–100 m above ground, during a brief heading deviation and correction, the winch cable likely auto-released from the CG hook due to increased cable angle while the glider remained in a steep attitude.
- Insufficient nose-down input: After cable release the crew apparently did not promptly and sufficiently lower the nose, so the glider continued at a high pitch attitude as the winch pull disappeared and airspeed decayed below stall speed.
- Stall and right spin: With airspeed below minimum and right rudder likely still applied from the heading correction, the glider stalled and entered a right spin from low altitude.
- Crash - fatal: After about one spin turn the Bocian impacted the hard-surface runway in a steep nose-down right rotation, destroying the glider and killing both occupants on impact.