Data has shown a North Sea helicopter flight dropped 2100 feet in the last 10 seconds of the flight.
Emergency services have been deployed following the incident close to Bergen, offshore Norway.
A total of 13 people were on board including 11 crew and two passengers when the incident happened.
The Norwegian Prime Minister has described the incident as “horrifying”.
For live updates on the incident click here.
A number has been set up for next of kin.