History of the Flight
On Saturday 31 August 2019, an Airbus Helicopters AS350 B3, registration LN-OFU, operated by Helitrans AS, was conducting sightseeing flights from the Høstsprell festival area at Kvenvikmoen, near Alta. The first flight carried five passengers and lasted approximately 10 minutes. The accident occurred on the second flight, which also carried five passengers and lasted about five minutes before the helicopter crashed. The helicopter was in descent and in a slight right turn at low altitude when the accident happened. It was heavily loaded, and its speed was increasing.
Injuries and Damage
All six persons on board—one pilot and five passengers—died. The helicopter was largely consumed by fire after impact, except for the tail boom. The post-crash fire broke out shortly after the crash.
Weather and Environment
Weather conditions and visibility were good in the area of the flights. The accident site was in the Skoddevarre mountains in Alta municipality, Troms og Finnmark county, Norway.
Aircraft Information
The helicopter was an Airbus Helicopters AS350 B3, registered LN-OFU, and was almost new. It was not equipped with a crash resistant fuel system. Newly produced AS350s have been delivered with such systems as standard from October 2019.
Investigation
The Norwegian Safety Investigation Authority (NSIA) conducted the investigation. Data from Flightradar24 and the operator's GNSS tracking system were used to reconstruct flight paths, but data from the final minute before impact was missing due to an ADS-B shadow caused by the terrain. The helicopter’s Appareo Vision 1000 recorder memory unit did not survive the fire. A Snapchat video sent by a passenger immediately before the accident was not provided to the NSIA by Snap Inc.
No technical faults or irregularities related to the helicopter that could have affected the sequence of events were found. The NSIA analyzed the available information and identified one probable sequence of events: the flight control hydraulic system may have reached its limit during maneuvering, triggering servo transparency. This situation may have occurred unexpectedly, and based on the last available altitude data, the helicopter likely had insufficient altitude above the terrain for the pilot to regain control.
Conclusion
The accident cannot be described as a high-energy accident. The survivability would have been significant had a fire not broken out shortly after the crash. The NSIA noted that a crash resistant fuel system would have reduced the fire risk.