Eurocopter AS350 B3 accident at Cormet de Roselend (F-GYBH)

Overview and flight details On 5 February 2013 at 10:50 local time, a Eurocopter AS350 B3 helicopter, registration F-GYBH, was destroyed when it overturned on its right side during a precautionary landing on a snow-covered surface at Cormet de Roselend, in the Savoie department (73), at an altitude of 1,960 metres. The aircraft was operated by a private aerial work company. The pilot was the sole occupant. ## Circumstances The pilot departed from a private helipad at Bourg-Saint-Maurice (73) for the Roselend dam to carry out an aerial work mission. On approach to the dam, a cloud mass prevented the pilot from continuing the flight. The pilot turned back, but deteriorating weather conditions made it impossible to return to the valley. The helicopter landed at the Cormet de Roselend site to wait for improved weather. When the skids contacted the ground, the pilot lowered the collective pitch. After mechanically locking the collective control, the helicopter overturned to the right. The pilot stated that he was unable to regain control because of the locked control. ## Weather and site conditions Estimated weather at the site was wind from 240° at 5 to 10 knots with gusts to 30 knots, scattered clouds between 1,200 and 1,500 metres, scattered clouds at 2,000 metres, and scattered clouds at 3,000 metres. At the accident site, a layer of fresh snow about 50 cm deep concealed ground irregularities. ## Pilot and aircraft The pilot held a commercial pilot licence (CPL(H)) issued in 2003 and had 9,000 total flight hours, including 8,800 hours on type, 100 hours in the preceding three months, and 2 hours in the preceding 24 hours, all on type. The helicopter was fitted with skid shoes at the rear of the skids. ## Conclusion The accident was attributed to an unsuitable landing technique on snow-covered ground. The pilot did not ensure the helicopter was stable before locking the collective pitch control and shutting down the engine. The thick snow layer, which concealed terrain irregularities, made selecting a landing site difficult.