What happened
On August 31, 2019, an Airbus Helicopters AS 350 B3, registration LN-OFU, crashed in the Skoddevarre mountains within the Alta municipality. The aircraft, operated by Helitrans AS, was conducting a sightseeing flight for passengers attending the Høstsprell festival. This was the second flight of the day; the first had been completed successfully. During the second flight, which lasted approximately five minutes, the helicopter was descending and performing a slight right turn at a low altitude. The aircraft was heavily loaded and gaining speed at the time of the impact. Following the crash, a fire broke out, consuming most of the wreckage and resulting in 6 fatalities (one pilot and five passengers).
The investigation
The Norwegian Safety Investigation Authority (NSIA) faced significant hurdles due to the intensity of the post-crash fire. Most of the aircraft was destroyed, making it impossible to retrieve electronic flight data or information from many onboard components. While the tail boom remained, the memory unit of an aftermarket Appareo Vision 1-000 recorder was lost to the fire. Investigators reconstructed the flight paths using GNSS-based tracking and Flightradar24 data, though terrain-induced signal shadows prevented a complete view of the final moments. The investigation also examined the aircraft's maintenance history, the pilot's training, and the survivability of the crash, noting that the aircraft lacked a crash-resistant fuel system.
Findings
While the NSIA could not definitively prove the exact cause due to missing data, the investigation identified a probable sequence of events. The investigators found no evidence of mechanical failure or technical irregularities. Instead, they concluded that the hydraulic flight control system may have reached its physical limits during the maneuver, triggering a phenomenon known as servo transparency. This occurs when aerodynamic loads exceed the hydraulic assistance provided by the actuators. Because the helicopter was at a low altitude and performing a maneuver, the pilot likely had insufficient time or altitude to recover control once the phenomenon occurred.
Safety action
The NSIA issued 12 safety recommendations following the analysis. These recommendations, addressed to EASA, the Norwegian Civil Aviation Authority, and Helitrans AS, focus on preventing servo transparency, improving the safety of commercial sightseeing operations, and enhancing survival capabilities. Key areas of concern included the implementation of crash-resistant fuel systems, the use of helmets, and the requirement for lightweight flight recorders.