What happened
During a medical evacuation mission in a wooded area, an AS 365 N3 helicopter attempted to land on snowmobile trails to pick up a patient. The crew, consisting of two pilots, a doctor, and a nurse, performed the landing on snow-covered terrain. Upon touchdown, the left main landing gear broke through the surface crust of the snow. This caused the aircraft to tilt significantly, leading the left stabilizer fin to strike the snow cover, which forced the left stabilizer half upward.
The resulting tilt of the aircraft exceeded the operational limitations of the control system, making it impossible for the pilots to lift the helicopter safely. To rectify the inclination, the crew members were instructed to dig holes in the snow for the right main landing gear to level the aircraft. Once the patient was successfully loaded, the helicopter departed for Gällivare. During the flight, the pilots encountered two nose-down movements that required correction by the autopilot before the aircraft reached its base.
The investigation
Following the incident, the crew discovered that the left stabilizer and the left vertical fin had been lost during the landing sequence. The Swedish Accident Investigation Authority examined the circumstances surrounding the landing and the physical state of the aircraft upon arrival at the base.
Findings
- The investigation determined that the primary cause of the incident was the inability to accurately assess the bearing capacity of the snow cover.
- The situation was further complicated by the operational difficulties associated with loading a patient with a spinal injury while the helicopter was in an unstable, 'light on wheels' state.