A helicopter crash that killed 13 people in Norway was caused by a technical fault, air accident investigators say.

Iain Stuart from Laurencekirk in Aberdeenshire was among those who died when the chopper went down near Bergen on Friday.

Accident Investigation Board Norway (AIBN) spokesman Kåre Halvorsen said the contents of the Super Puma's flight recorder gave no indication the crash was caused by human error.

He said the whole incident appeared to have taken place in less than a second after the helicopter's rotor blades detached.

Mr Halvorsen said: "As most people probably know, the rotor disk left the helicopter before the helicopter itself ended up in the ocean. Based on the facts we have ... we know that this is a technical accident.

"It's not an accident caused by human error on board the helicopter. We know that the accident developed very, very fast from a normal situation to the accident being a fact."

Most of the wreckage has been taken to Haakonsvern naval base but some parts remain missing.

On Sunday, it emerged helicopter operator CHC had replaced parts on the Super Puma after a warning light earlier in the week.

Norwegian Civil Aviation Authority legal adviser Hege Aalstad said the helicopter had both its gearbox and rotor head replaced in the months before the crash.

The AIBN is working with the UK's Air Accident Investigation Branch (AAIB) to decipher data from the helicopter's black box, which has been sent to Britain. The AIBN described the data as "of good quality".

Mr Stuart's family said they have been left "devastated" by the Haliburton employee's death.

They said: "We as a family are devastated at the loss of Iain in Friday's tragic helicopter crash in Norway.

"Iain was a loving husband and devoted father to his two children and as a family we are heartbroken. He was a caring son, brother, uncle and friend to many."

Danny Lonie, managing director of offshore training firm Allied Training, was due to fly back to Scotland on the helicopter the day it crashed.

He said: "We were aboard the Safe Caledonia and were due to be picked up by the helicopter on Friday at 1pm. We heard about the crash at 12.30pm but we didn't realise it was our chopper at the time.

"Another helicopter flew us back to Amsterdam and then on to Aberdeen on Saturday. It's horrible what's happened but at the end of the day it's just machine.

"I know for a fact that every helicopter agency in Aberdeen is doing everything they can to keep people as safe as possible.

"I'll be going back out again next week, I'm not worried."