Accident de Phoebus C lors d'une approche turbulente à l'aérodrome de Montricher
Le 29 juin 1971, un planeur Bölkow Phoebus C a rencontré des difficultés lors de son approche finale à l'aérodrome de Montricher en Suisse. Le pilote, après s'être libéré du remorquage près d'Orbe, visait à planer jusqu'à Montricher mais a été confronté à de fortes turbulences et des courants descendants. Lors de l'approche de la piste 03, le planeur a décroché et s'est écrasé, se retrouvant inversé dans un champ. Le pilote a subi de graves blessures et le planeur a été considérablement endommagé. L'enquête officielle a confirmé que l'accident résultait d'une perte de vitesse dans des conditions de vent de travers turbulent.
- Aerotow cross-country: The pilot was aerotowed from Neuchâtel and released near Orbe at about 1700 m MSL to glide toward Montricher airfield.
- Turbulent crosswind joran: At Montricher a W–NW joran wind of 10–15 knots produced moderate turbulence and downdrafts near the terrain, creating challenging approach conditions.
- Low, close downwind: During the left-hand downwind for runway 03, the pilot ended up too low and too close to the runway axis, likely underestimating the strength of the crosswind.
- Strong turbulence encountered: While flying the left-hand downwind leg for runway 03, the glider encountered strong turbulence and downdrafts that caused a rapid loss of altitude.
- Circuit shortened: As altitude decreased quickly, the pilot shortened the landing circuit and initiated a final 180° turn about 150 m before the runway threshold.
- Stall in final turn: In the turbulent air during the 180° turn toward runway 03, the glider’s airspeed became insufficient, it stalled on the left wing, and the pilot lost control.
- Crash - serious injury: The glider descended to the ground and came to rest inverted in a field near Montricher at 19:15, seriously injuring the pilot and causing severe damage to the aircraft.