Incident Overview
On April 27, 2002, at approximately 16:45 local time, an Airbus Helicopters AS350B2 (Ecureuil) with registration HB-XUZ crashed into the snow-covered slopes of Sustenhorn in the municipality of Gadmen, Canton of Bern, Switzerland. The aircraft was operated by Heliswiss, based at Belp Airport, and was engaged in a commercial Visual Flight Rules (VFR) mission to transport skiers.
Operational Context
The helicopter had been reserved to shuttle an eleven-person group for skiing activities. After initial delays due to overcast conditions, the flight operations commenced successfully with several trips between the Hotel Steingletscher and the Sustenlimi ski area. During the fourth leg of the operation, after dropping off passengers at the Sustenlimi, the pilot observed deteriorating weather conditions characterized by forming fog banks.
Accident Sequence
The pilot attempted to return to the Steingletscher but reported being surprised by the rapid change in visibility. A ground helper noted that fog had cleared at their location, but the pilot lost all visual references against the white snow-covered background. The helicopter struck the ground with its front skids, which broke upon impact. The aircraft overturned, destroying the cabin. The pilot sustained serious injuries, including a broken leg and facial lacerations, but survived due to the energy absorption by the snow and the absence of direct rotor blade contact.
Investigation Findings
Technical inspections revealed no mechanical failures or anomalies in the control systems that could have contributed to the accident. The rear drive shaft was severely twisted, indicating high energy in the rotor system at impact. Meteorological data confirmed the presence of altocumulus banks and low visibility conditions typical for the region during a cold front passage. The investigation concluded that the accident resulted from a collision with a snow-covered surface following a loss of visual references.