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Investigation of air accident in the Skoddevarre mountains, south of Alta, Norway

In the afternoon of Saturday, 31 August 2019, the helicopter was taking participants of a cultural event (Høstsprell) for sightseeing flights. During one such flight, the helicopter hit the ground in the mountains. There was a fire after impact. All six occupants, pilot and five passengers, lost their lives in the accident.

The Accident Investigation Board has completed the work at the accident site in Skoddevarre. It has been a demanding job both because of the impact itself, but mostly because of the intense heat that followed. The components from the helicopter are being transported to SHT's premises in Lillestrøm where the further investigation work continues. The French state Aviation Accident Investigation Bureau (BEA) together with representatives from the helicopter and engine manufacturers are involved in the investigation.

Light helicopters, such as the accident helicopter, of the type Airbus Helicopters AS 350 B3e, are not required to bring fire and crash protected devices for storage of sound and data. Nevertheless, Airbus Helicopters has chosen to deliver all newer helicopters of the type with a simpler storage unit. It does not have the same shock and heat protection as for those mandated for heavy aviation. Unlike mandatory storage devices in heavier aircraft, the memory unit also stores video showing the dashboard and views through the cockpit window. Furthermore, the unit stores GPS data (speed, position and altitude), the position of the helicopter in all axes and sound image from the engine and gearbox. This memory device has been found and attempts will be made to download data in the laboratory of the French Accident Commission (BEA) in France. The unit has severe heat damage. Data is normally also stored in other components of the helicopter. These devices are all damaged to a degree that it is not possible to retrieve data.

Assistance from local resources has been outstanding. Among other things, the Police and Norwegian Civil Defense searched  the terrain for any possible parts from the helicopter.

Update 31 August 2021

The Norwegian Safety Investigation Authority has completed a draft report after the helicopter accident near Skoddevarre two years ago. A final review of both the Norwegian and English versions is required before it is sent to the involved parties for consultation. The involved parties in this case is the Civil Aviation Authority Norway (CAA-N), the European Aviation Safety Agency (EASA), the International Civil Aviation Organisation (ICAO), Bureau d'enquêtes et d'analyses pour la sécurité de l'aviation civile (BEA) with its experts from the helicopter manufacturer (Airbus Helicopters) and the engine manufacturer (Safran Helicopter Engines), the Swedish Accident Investigation Authority and finally the helicopter operator (Helitrans). After current international conventions and regulations, the recipients have sixty days to reply with their comments after receiving the draft of the final report for consultation. After all comments are received the report will be amended before public release.

The report and the safety recommendations are presented with the aim to reduce the probability of similar accidents occurring in the future. The investigation has been complicated and challenging.

The Norwegian Police’s request to Snap Inc. in The United States to get a hold of a video of the accident was not granted.

Status for the investigation 28.08.2020

The NSIA is now in the final phase of the investigation of the helicopter accident a year ago. Work is still ongoing against Snap Inc. in the US to access any possible vital information on the Snapchat video from the last part of the flight. The police are working to gain access to the information.

Update 9 July 2020

At this point in the investigation, no unambiguous findings have emerged that can explain the accident. The National Safety Investigation Authority (NSIA) has pursued several possible scenarios/hypotheses, but none of them can adequately explain the immediate cause of the accident.

The NSIA has compiled data from the flight following system that the operator company Helitrans had installed in the helicopter and detailed data from Flight Radar 24. The NSIA has thus established a detailed picture of the helicopter’s flight path, both on the first sightseeing flight with passengers and on the flight when the accident happened.

A comparison between the ground speed and flight path recorded by Flightradar24 and the corresponding data transmitted by the Cello Track 3Y unit on board the helicopter confirms the reliability of the signals (Red: Cello Track 3Y, yellow: Flightradar24). The first and final parts of the flight are not shown due to inadequate signals because of varying topography.

 

Several Snapchat videos were sent from both flights. The NSIA has conducted audio analyses of these videos to determine whether there could have been technical faults in any of the helicopter’s rotating components. The analyses have not found anything out of the ordinary. The videos have also been useful to be able to understand how the helicopter flew when the videos were recorded.

At an early stage of the investigation, the NSIA was made aware of a Snapchat video that was most likely sent to one recipient only during the final seconds of the flight. Once the recipient had opened and watched the video, the content became unavailable. The police arranged for the sender’s user account to be preserved by Snap Inc. in the USA. If the video is available on Snap Inc.'s server and the NSIA is granted access to it, the content may play a crucial role in explaining the accident.

Regardless of whether or not it results in a clear conclusion, the investigation can contribute to improving safety. Shortly after the accident, the helicopter manufacturer Airbus Helicopters decided that, in future, this type of helicopter will only be available with a fuel system with better crash protection than the one installed in the helicopter involved in the accident. Also, more attention is given to the protection of stored data. This will increase the likelihood of it being possible to retrieve data after an accident.

Update 24 October 2019

The Accident Investigation Board Norway (AIBN) has not concluded among various scenarios that may have led to the accident in Alta on 31 August 2019. It early became clear that we only had one half of the 6 front bolts, which together with a flexible coupling, connect the engine to the main gearbox. The main gearbox drives the main rotor, thus the helicopter cannot continue flight if the coupling fails. This is one of several possible scenarios for the accident. The Accident Investigation Board Norway has, assisted by Norwegian Armed Forces and local police in Alta, searched the crash site, and in the terrain below the believed flight track. We have now found 10 out of 12 halves and almost all the fragments of the flexible coupling. All the bolts were found on the crash site. The finding helps us understand how, and when the shaft disconnected. So far we have not concluded whether this happened on the ground at the moment of impact or while airborne. Consequently it is not concluded whether or not the engine to the main gearbox drive shaft has been a factor in the accident. At the same time other scenarios are being investigated.

Any possible data from the analysis of the memory unit from the helicopter is yet to come.

The Accident Investigation Board Norway cooperates well with the French Accident Investigation Board BEA, the helicopter manufacturer Airbus Helicopters and the engine manufacturer Safran Helicopter Engine in the investigation.

Update 11 September 2019

Airbus Helicopters issues an Emergency Alert Service Bulletin following preliminary findings in connection with the investigation of the accident in Alta, Norway Saturday 31 August 11.09.2019

The first detailed examinations of components from the Airbus Helicopters AS 350 B3E helicopter, LN-OFU brought to the AIBN premises was performed Tuesday. The work is in cooperation with the French Aviation Accident Investigation Bureau (BEA) with its technical advisors from Airbus Helicopters and the engine manufacturer Safran Helicopter Engines

Preliminary findings linked to the connection between the engine and the main gearbox has lead AH to issue an Emergency Alert Service Bulletin (EASB) calling for immediate visual inspection of this area for recently delivered AS350, AS550 and EC130 helicopters. According to Airbus Helicopters, issuance of the EASB is a precautionary measure to ensure the continued airworthiness of the helicopter type.

The helicopter had less than 73 flight hours since new. The AIBN has no indication that the operator of the accident helicopter, Helitrans AS, has performed work other than visual inspection in the affected area.

The examinations of the accident helicopter is still ongoing. The AIBN has, at this stage, not concluded whether, or not, failure of the connection between the engine and the main gearbox is a causal factor. In order to obtain a complete understanding of the accident, the AIBN needs to hold together all information from the examined components, possible data from the storage unit, accident site observations, witness observations and testimonies from all parties involved in manufacture, maintenance and operations of the helicopter.

The memory chip from the helicopter’s data storage unit is still being examined. The memory chip had severe heath damage, even beyond the first impression.

Search for parts. Photo AIBN
The Police and Norwegian Civil Defense combed the terrain in the search for parts from the helicopter. Photo: AIBN



The memory device from the storage unit (Appareo Vision 1000). Photo: AIBN


The last lift. Photo AIBN
The last components are being transported from the accident site. Photo: AIBN


The components from LN-OFU. Photo AIBN
Components from LN-OFU laid out in the AIBN hangar. Photo: AIBN

Latest update: 31.08.2021

Facts

Location Skoddevarre, south of Alta in Finnmark county, Norway
Occurrence date 31.08.2019
ICAO Location indicator ENAT
Aircraft Airbus Helicopter AS 350 B3 Ecureuil
Operator Helitrans AS
Registration LN-OFU
Meteorological conditions VMC
County Finnmark
Type of occurrence Accident
Type of operation Commercial, other
Category of operation Light, helicopter (<= 2 250kg)
Aircraft category Helicopter, Single-engine, Turboprop/turboshaft
FIR/AOR ENBD (Bodø ATCC)

Reports - same aircraft model

Reports - same category of operation