Mucha 100 A crashes into forest after stall at Siblinger Randen, pilot injured
On July 31, 1966, a Mucha 100 A glider crashed into a forest near Siblinger Randen, Switzerland. The pilot was executing a low-altitude turn when the aircraft stalled in moderate turbulence, causing the left wing to clip trees. The glider suffered significant damage, but the pilot sustained only minor injuries. The incident was attributed to inappropriate flight tactics and violation of altitude regulations.
- Aerotow ridge flight: The pilot aerotowed from Schaffhausen and released at about 200 m above the airfield, then proceeded to fly along the west slope of the Siblinger Schlossranden in weak ridge lift.
- Low, weakening lift: As the pilot continued north along the Churztal, the initial 1 m/s climb decreased to zero and then to 0.5–1 m/s sink, with his height above ground reducing due to sink and rising terrain.
- Very low ridge height: By the time he reached the northern part of the Churztal, his height above ground had dropped below the recommended 50 m minimum for ridge flying, leaving little margin to recover from disturbances.
- Low-altitude turn in lee: In moderate turbulence and lee sink in the northern Churztal, the pilot initiated a left 30° bank reversal turn at low altitude to head back south along the ridge.
- Speed decay and sink: Shortly after starting the turn, the airspeed suddenly decreased and the glider began to mush and sink, likely due to turbulence and/or unintentional back pressure at low speed.
- Attempted recovery: The pilot pushed the stick forward and left to regain airspeed and move away from the slope, but the very low height above the rising terrain made recovery impossible.
- Crash - minor injury: The left wingtip struck trees and the glider crashed into the forest below the Steinmürlichopf, destroying the fuselage and slightly injuring the pilot.