What happened
On May 13, 1972, a K-8B glider, registration HB-778, was engaged in a flight at Grenchen Airport as part of a flight duration requirement for the Silver C badge. After completing a five-hour flight, the pilot initiated the return to the airfield. During the approach, the pilot failed to sufficiently compensate for a significant headwind, resulting in an approach path that was too low.
In an attempt to extend the flight path, the pilot maneuvered to fly over a road crossing the runway. While this maneuver was initially successful, the aircraft's speed dropped to between 80 and 85 km/h. Consequently, the glider lost lift and dropped sharply near the ground, coming to a halt on the airfield at approximately 17:13. The pilot sustained no injuries, though the aircraft suffered heavy damage.
The investigation
The investigation examined the pilot's credentials, the aircraft's airworthiness, and the meteorological conditions at the time of the accident. The pilot held a valid glider license with passenger authorization and possessed 37 hours of total flight experience, including 29 hours on this specific aircraft type. There was no evidence of medical impairment or prior incidents in the pilot's record.
Technical inspections confirmed that HB-778 was airworthy and that the weight and balance were within prescribed limits. No pre-existing mechanical defects were identified as contributing factors. Meteorological data indicated a weak high-pressure system over Switzerland with a northeast wind of 5 to 10 knots and excellent visibility of 50 km.
Findings
- The pilot misjudged the required altitude for the landing approach.
- The pilot did not adequately account for the strong headwind during the descent.
- In an effort to correct the low approach, the pilot increased the angle of attack at a low airspeed, causing the aircraft to fall below its minimum flying speed and stall/drop near the ground.