What happened
On March 14, 2016, a private Robinson R44 Raven II helicopter, registered LN-OCX, was conducting a flight from a holiday home in Jämtland County, Sweden, toward Værnes Airport in Norway. The flight began under favorable weather conditions, but as the aircraft moved from forested areas into the alpine region, visibility decreased. Seeking better visual references, the pilot diverted south toward Storlien.
During this diversion, the crew encountered a rain shower and significantly reduced visibility. The pilot decided to land on the alpine terrain to wait for better conditions. After landing, the pilot briefly left the aircraft on foot to scout the surrounding landscape, noting that the terrain sloping toward Storlien offered better visibility. Upon returning to the helicopter, the pilot attempted to take off to continue the flight.
As the pilot initiated the hover by lifting the nose, a gust of wind from the left struck the aircraft. The rear part of the right skid sank into the snow, causing the helicopter to undergo a dynamic rollover, resulting in the aircraft lying on its side. The two occupants and two dogs on board were uninjured, though they had to exit the aircraft due to the smell of fuel. The helicopter sustained substantial damage.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the wreckage and interviewed the pilot, the passenger, and a rescuer. The investigation focused on the aircraft's configuration and the environmental conditions at the time of the accident.
Investigators found that the snow cover was approximately one meter deep with a crust. While the crust could support a person, it was prone to breaking. The technical examination of LN-OCX revealed that the aircraft was not equipped with specialized landing pads (often called "laddor") designed for snow operations. Additionally, the investigation noted that the helicopter lacked the high-visibility contrast markings required for operations in Swedish mountain areas.
Findings
- The primary cause of the accident was that the helicopter was not appropriately equipped for landing in snow, meaning the load-bearing capacity of the snow cover could not support the weight applied to the rear of the right skid during takeoff.
- A wind gust from the left contributed to the incident by increasing the aircraft's rightward tilt, further loading the rear of the skid into the snow.
- The absence of specialized landing pads allowed the skid to penetrate the snow crust, triggering the dynamic rollover.
- The lack of contrasting color markings on the aircraft made it difficult for rescuers to locate the wreckage in the white, alpine environment.