Speed Astir II collision with transport cable at Stanserhorn, Switzerland
On June 5, 1983, a Grob Speed Astir II was involved in a competition flight originating from Lucerne-Beromünster. While attempting to gain altitude over Stanserhorn, the pilot collided with a transport cable. The glider crashed into a forest, resulting in severe injuries to the pilot and significant damage to the aircraft. The transport cable remained intact, and no significant third-party damages were reported. The investigation confirmed the collision with the cable as the cause of the accident.
- Aerotow competition start: The pilot aerotowed from Luzern-Beromünster at 14:36 local time to begin a regional competition triangle task Beromünster–Sörenberg–Engelberg–Beromünster.
- Poor lift en route: On the leg toward the first turnpoint Sörenberg, the pilot encountered only sinking air in the Pilatus area, forcing him to fly much lower than originally planned.
- Low-altitude cable area: Despite prior briefing warnings about cable hazards and the presence of many transport cables in the area, the pilot continued flying low in terrain where such obstacles were known to exist.
- Did not abandon task: The pilot lacked the determination to abandon the competition flight early despite deteriorating soaring conditions and increasing risk near terrain and cables.
- Low climb attempt Stanserhorn: Seeking to regain altitude, the pilot diverted to the west side of Stanserhorn and flew along the slope searching for lift at about 60 m above ground.
- Collision with cable: While flying with approximately 19° left bank along the Stanserhorn slope, the glider’s left wing struck a transport cable, cutting into the leading edge.
- Crash - serious injury: Following the cable strike, the glider entered a left turn and crashed into a forest, severely injuring the pilot and heavily damaging the aircraft, while the cable remained intact.