Bell 47 G3 helicopter and B-4 sailplane collision near Sanetschpass results in three fatalities
On July 15, 1978, a mid-air collision occurred between a glider (HB-1259) and a helicopter (HB-XFA) approximately 3 km NNW of Sanetschpass. The glider had taken off from Saanen at 10:50 AM and was released from tow five minutes later. The collision happened around 12:25 PM, resulting in both aircraft crashing onto a snow-covered scree slope, with all occupants fatally injured. The probable cause was the pilots' failure to see each other in time, exacerbated by challenging visibility conditions.
- Aerotow to cruise: The glider HB-1259 was aerotowed from Saanen at 10:50 and released after about five minutes near the south slope of Eggli to begin an alpine soaring flight.
- High-traffic glider zone: The flight took place within an active alpine glider zone near Sanetschpass, designated as a danger area with concentrated soaring activity.
- Poor mutual visibility: Flight tests later showed that a B-4 glider is very hard to see from a Bell 47 and that the helicopter is not audible from the glider, making see-and-avoid difficult.
- Converging flight paths: Around 12:25 the glider, circling north-northwest of Sanetschpass, and the helicopter flying toward Valais approached each other on nearly opposite headings at similar altitude without visual acquisition.
- No effective avoidance: Neither pilot initiated an avoidance maneuver, indicating that the opposing aircraft was not seen in time to react.
- Rotor strikes glider: The helicopter’s main rotor disc intersected the glider’s fuselage at about a 55° bank angle, cutting the B-4 longitudinally through the cockpit and right wing root and fatally striking the glider pilot.
- Crash - fatal: Both the disintegrated glider and the damaged helicopter fell onto the snow-covered scree slope at Lapi di Bou NNW of Sanetschpass, destroying both aircraft and killing all three occupants.