History of Flight
The pilot, employed by Heliswiss, was assigned a heliski mission the previous day. On 8 March 2009, he departed from Gruyère aerodrome (LSGT) with a flight assistant and two passengers, landing at Gstaad Grund (LSHA) at 09:15. Shortly after 11:00, he took off from Gstaad Grund with four passengers and ski equipment to drop them at the Wildhorn summit (altitude 3246 m). This landing was normal, with weather conditions matching forecasts: wind 320° at 25 kt, temperature -5 °C. The pilot then flew solo to Daillon to pick up the next group.
At 12:30, the pilot departed Daillon with four passengers and a mountain guide. The planned flight was a scenic tour over Vallon d’Arbaz and a drop-off at the Wildhorn summit. During the climb, the pilot observed snow being blown off the ridge and summit, indicating stronger wind. He also noted the wind had shifted to the southwest. The first approach from the east was aborted due to wind and turbulence; the pilot disengaged to the south. A second approach with a steeper angle aimed to reduce turbulence, but was also aborted. In agreement with the guide, the pilot decided to land on the southern slope of the massif, between the Wildhorn summit and the western part of the Glacier des Audannes—a spot he had used before.
During the turn before the third approach, the pilot noticed snow whirls on the glacier plateau, confirming turbulence and gusts at ground level. The third approach was from the east with a shallow descent angle. In hover at about 2 m above the ground, the pilot yawed the helicopter right about 45°, touching down first with the right ski tip, then the left, aligning the nose uphill. He gradually lowered the collective lever to complete the landing.
A gust of wind caused the helicopter's rear to lift. The pilot attempted to correct by moving the cyclic rearward, but the helicopter pitched forward-right, and the main rotor blades struck the ground. The helicopter yawed left, rolled onto its right side, and the turbine stopped on impact. All occupants exited unharmed; the pilot returned to shut off fuel pumps, call for help by radio, and cut electrical power. No fire occurred. Three passengers, including the guide, skied down; the pilot and two passengers were rescued by a helicopter.
Meteorological Information
MeteoSuisse and the pilot's testimony provided weather data. A low-pressure system over Scotland brought an Atlantic front across the Alps. The warm front reached the northern Alps during the morning, with the cold front arriving only in the evening. At the accident site, the pilot reported wind from the southwest with turbulence and gusts, as evidenced by snow blowing off the ridge and snow whirls on the glacier.
Aircraft Information
The helicopter was an Eurocopter AS350 B3, registration HB-ZEI, operated by Heliswiss. The pilot held a professional helicopter pilot license (CPL(H)), valid until 7 January 2014, and a class/type rating for AS350 valid until 14 February 2010. He had 2131:43 hours total flight time, with 260:12 hours on type. The aircraft sustained severe damage but no third-party damage.
Cause
The accident was caused by a collision of the main rotor with the ground after a loss of control during landing on a snow-covered slope with crosswind and turbulence. A contributing factor was the choice of a location unsuitable for passenger disembarkation.