What happened
On June 5, 1971, at approximately 16:05, a Fuji FA 200-180, registration HB-ESV, departed from runway 12 at Bad Ragaz airport. The aircraft was carrying a pilot and three passengers on a private flight bound for Kägiswil. During the takeoff roll, the aircraft encountered a strong headwind of approximately 25 knots. After accelerating slightly above normal rotation speed, the pilot lifted the aircraft into a climb that witnesses described as very steep.
As the aircraft continued its straight-line flight, it began to lose altitude. To avoid the Büel terrain located at the end of the runway, the pilot initiated a slight left turn. This maneuver, combined with local crosswind components, caused the aircraft to drift further left. Fearing a collision with the tower of St. Leonard Church, which sat roughly 200 meters to the side, the pilot increased the leftward turn. This action caused the rate of descent to accelerate. At approximately 16:06, the aircraft struck trees in an orchard northwest of Bad Ragaz, roughly 400 meters past the runway end and 200 meters left of the runway centerline. There were no injuries among the occupants, though the aircraft was destroyed and minor third-party property damage occurred.
The investigation
The investigation examined the aircraft's mechanical condition, the pilot's experience, and the meteorological conditions at the time of the accident. The pilot held a valid private pilot license with 440 total flying hours and showed no signs of health impairment. The Fuji FA 200-180 was found to be airworthy, with the only noted issue being a stall warning device that appeared to be set slightly too late.
Meteorological analysis revealed that shortly before 16:00, thunderstorm-related southeasterly winds of up to 25 knots had emerged, creating moderate turbulence and updrafts/downdrafts near the terrain. The investigation focused on how the interaction between these winds and the pilot's maneuvers led to the loss of altitude.
Findings
- The aircraft entered a region of turbulent downdrafts caused by winds from the south hitting the terrain at the end of the runway.
- The pilot entered the lee side of the Büel hill, resulting in a sudden drop in stagnation pressure.
- While the aircraft was likely at a high angle of attack, the pilot initiated a left turn, which further increased the angle of attack.
- This sequence of maneuvers caused the aircraft to gradually enter an aerodynamic stall.