Grunau Baby II crashes into trees near Zweisimmen after prolonged flight
On August 8, 1962, a Grunau Baby II piloted by a student pilot crashed into a wooded hillside near Zweisimmen, Switzerland, after a nearly four-hour flight. The incident occurred when the pilot attempted to gain altitude in diminishing lift conditions. The aircraft sustained significant damage, but the pilot was unharmed. Investigations revealed a defect in the rudder control system, although it was not deemed the primary cause of the crash. The accident was likely due to the aircraft stalling in close proximity to the terrain.
- Aerotow ridge flight: The student pilot aerotowed from Zweisimmen at 14:20 for a solo ridge/wave soaring flight in the Grunau Baby II, later climbing in wave lift to about 3300 m.
- Very low experience: The pilot had only about eight hours total glider time, with limited solo duration experience prior to this flight.
- Excessive flight duration: Contrary to training guidelines limiting early soaring flights, the student remained airborne for nearly four hours, leading to probable fatigue.
- Diminishing evening lift: Towards evening the wave lift weakened, and around 18:00 the pilot was down to about 800 m above the valley floor near St. Stephan with the valley already in shadow.
- Low, close-in ridge soaring: Instead of committing to landing, the pilot attempted to gain more height in weak, localized lift by flying repeatedly close along the steep, forested west slope of the Girshubel.
- Stall near terrain: In the weakening upslope lift while maneuvering close to the hillside, the glider was probably flown into an over‑stalled condition with reduced control effectiveness at low height.
- Crash - no injury: At about 18:12, after roughly 3 hours 50 minutes of flight, the glider flew into trees on the Girshubel slope, heavily damaging the wings while the pilot remained uninjured.