What happened
On November 27, 1971, a flight instructor and a student pilot were conducting a check flight in a Bocian glider, registration HB-719, at Bad Ragaz airfield. The flight began as a towed operation, departing from runway 30 at approximately 14:45. Shortly after reaching an altitude of roughly 160 meters, the towing aircraft turned right, moving away from the airfield and into patches of fog.
In response to the deteriorating visibility, the instructor released the tow rope with the intention of returning immediately to the airfield. However, due to the presence of fog, the crew was unable to locate the airfield. This forced them to execute an off-field landing. During the final approach, the crew performed a steep right-hand turn at low altitude to avoid obstacles that were only identified at the last moment. During this maneuver, the right wingtip of the Bocian struck the snow-covered ground, leading to a hard impact at 14:50. The accident occurred north of the village of Bad Ragaz.
While the instructor remained uninjured, the student pilot sustained light injuries. The aircraft was heavily damaged, though no third-party property was affected.
The investigation
The investigation examined the meteorological conditions and the decision-making process of the crew. While nearby stations reported clear conditions, local data indicated that patches of fog were drifting into the Ragaz area from the direction of Vaduz. The investigation established that fog patches were closer to the airfield than the pilots had initially estimated. Furthermore, high relative humidity facilitated the rapid formation of new fog patches, and diffuse lighting likely further degraded visibility.
Findings
- The crew made an avoidable error in assessing the meteorological situation, deciding to proceed with the takeoff despite the potential for deteriorating visibility.
- The presence of fog patches near the airfield and the rapid formation of new fog due to high humidity contributed to the loss of visual contact with the airfield.
- The primary cause of the accident was the glider's collision with the ground during a steep, low-altitude turn executed to avoid obstacles during an off-field landing.