Crash du Grob G-103A Twin II Acro lors d'un vol de pente près de Claro, Suisse
Le 10 avril 1999, un Grob G-103A Twin II Acro a été impliqué dans un accident près de Claro, Suisse. Le planeur, piloté par un ressortissant suisse, a perdu le contrôle lors d'un vol de pente et s'est écrasé dans une zone boisée. Le pilote a subi des blessures légères, tandis que le passager a été grièvement blessé. L'appareil a été complètement détruit. Le rapport officiel a identifié la cause comme une perte de contrôle due à des tactiques de vol en montagne inadéquates.
- 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.