What happened
On 20 June 2011, two German-registered helicopters were conducting a private flight from Leksand to Östersund. The first helicopter, D-HPHP, was approaching a landing site in Salixbyn, Jämtland, to join a second helicopter, D-HALP, which had already landed to allow a passenger a break. The landing site was chosen by the passenger on the ground, who used radio communications and hand signals to guide the pilot.
As the pilot of D-HPHP attempted to touch down, the left landing skid made contact with the ground first. Because the terrain was uneven and sloped toward a nearby lake, the aircraft momentarily tipped backward. The pilot attempted to correct this by adjusting the collective and cyclic controls, but this maneuver caused the helicopter to tip and move forward. This movement triggered a rightward yaw, causing the aircraft to rotate. During this rotation, the tail rotor of D-HPHP struck the main rotor blades of the stationary D-HALP. The resulting impact caused the main rotor blades of D-HPHP to strike the ground and a nearby woodshed, leading to severe structural damage to the airframe, including the tail boom and rotor blades.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the technical condition of the aircraft, the terrain, and the subsequent rescue response. The technical inspection confirmed that the engine and steering controls were functioning normally prior to the impact. The investigation focused on the physical dimensions of the landing area relative to the helicopter's rotor diameter and the suitability of the ground surface.
Additionally, the SHK investigated the timeline and efficiency of the emergency response. The investigation revealed significant delays in the rescue operation, noting that the first fire station was not alerted until 27 minutes after the initial emergency call was received. The inquiry also scrutinized the communication of geographical coordinates between the SOS Alarm center and the responding rescue units.
Findings
- The primary cause of the accident was the unsuitable landing site, which was characterized by uneven ground and a slope that induced an uncontrolled tip during touchdown.
- The limited obstacle-free area provided insufficient margin for the pilot to perform necessary corrective maneuvers.
- The rescue operation was severely hindered by a lack of standardized procedures for communicating geographical positions in rural areas without street names.
- Discrepancies in map systems and coordinate usage between the SOS center and the rescue services led to the emergency vehicle driving past the accident site.