Accidente del Grob G-103A Twin II Acro durante vuelo de ladera cerca de Claro, Suiza
El 10 de abril de 1999, un Grob G-103A Twin II Acro estuvo involucrado en un accidente cerca de Claro, Suiza. El planeador, pilotado por un ciudadano suizo, perdió el control durante un vuelo de ladera y se estrelló en una zona boscosa. El piloto sufrió heridas leves, mientras que el pasajero resultó gravemente herido. La aeronave fue completamente destruida. El informe oficial identificó la causa como una pérdida de control debido a tácticas de vuelo en montaña inadecuadas.
- Ridge soaring flight: After aerotow departure from Magadino and several hours of cross‑country soaring, the pilot was ridge and thermal soaring along the Parusciana area north of Castione at about 1100 m MSL.
- Low height near slope: While following the ridge toward Pizzo di Molinera, the glider was flown at an estimated 100 m above ground and 50–100 m laterally from the slope, leaving little margin for recovery.
- Inadequate speed margin: The pilot flew at about 90 km/h in conditions with forecast wind shear and turbulence, without increasing speed above normal minima despite the low altitude and mountain environment.
- Encountered strong sink: During a wide left turn following the ridge, the glider transitioned from weak lift into a strong downdraft, abruptly reducing angle of attack and lift at an already low airspeed.
- Stall and loss of control: At low speed and low height, the glider stalled and the pilot lost control, with insufficient altitude available for recovery.
- Crash - serious injury: The stalled glider descended into the forested slope near Claro, destroying the aircraft, seriously injuring the front‑seat passenger and slightly injuring the pilot.