What happened
On August 31, 2019, an Airbus Helicopters AS 350 B3, registration LN-OFU, crashed in the Skoddevarre mountains within Norway's Alta municipality. The aircraft, operated by Helitrans AS, was conducting a sightseeing flight for passengers attending the Høstsprell festival. The flight was the second of the day and had been in the air for approximately five minutes when the accident occurred. During a descent and a slight right turn at low altitude, the heavily loaded helicopter struck the terrain. A fire broke out immediately following the impact, consuming most of the wreckage and resulting in six 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, which destroyed the majority of the aircraft and rendered electronic flight data unrecoverable. While the tail boom remained intact, the memory unit of an onboard Appareo Vision 1000 recorder was lost to the flames. Investigators reconstructed the flight path using GNSS-based tracking and Flightradar24 data, though terrain-induced signal shadows prevented a complete view of the final moments. The investigation included metallurgical examinations of components and a review of the operator's training and maintenance protocols.
Findings
Investigators found no evidence of mechanical failure or technical irregularities in the aircraft's systems. However, the analysis suggests the accident was likely caused by servo transparency, a phenomenon where aerodynamic loads during maneuvers exceed the hydraulic assistance provided by the actuators. The investigation concluded that the flight control hydraulic system may have reached its physical limits during the turn, leaving the pilot with insufficient control authority to avoid the terrain. Additionally, while the aircraft was relatively new, it lacked a crash-resistant fuel system. The NSIA determined that the post-crash fire was a decisive factor in the fatalities, noting that the impact itself was not a high-energy event and might have been survivable had the fuel system prevented the subsequent blaze.
Safety action
The NSIA submitted 12 safety recommendations to EASA, the Norwegian Civil Aviation Authority, and Helitrans AS. These recommendations focus on preventing servo transparency, improving the safety of commercial sightseeing operations, enhancing survival equipment (such as the use of helmets), and implementing requirements for lightweight flight recorders and crash-resistant fuel systems.