Investigations were under way today after 18 people survived when a helicopter ditched into the water near a North Sea platform.
All passengers and crew on board the Super Puma helicopter were rescued after it plunged into the sea around 125 miles east of Aberdeen while on the way to a BP production platform last night.
Three were flown to Aberdeen Royal Infirmary with minor injuries and were later discharged.
The remaining 15 were shipped into Aberdeen Harbour early today and were said to be "in good spirits".
The Air Accidents Investigation Branch launched an investigation into what went wrong, sending nine people to the city today.
Grampian Police also said it would be investigating the circumstances of the incident along with other agencies.
Officers spent around an hour on board the Caledonia Victory with the survivors while it was berthed at Aberdeen Harbour today.
They were taken from the harbour by bus at around 8am.
The offshore union RMT said it would be "monitoring closely" the accident investigation to pinpoint the cause of the crash.
The union's offshore organiser, Jake Molloy, said: "We will be looking very closely at the accident investigation."
The company said it was assisting Bond - who owned the stricken helicopter - with the support of Technip, in the recovery of the helicopter using the Wellservicer vessel.
BP's North Sea managing director Bernard Looney said now that those on board were being returned to their families, the company's attention would turn to the cause of the crash.
He said: "We will be co-operating fully with the Air Accident Investigation Bureau, Bond Helicopters and local agencies as they work to establish the cause of the incident.
"Our safety and emergency response systems worked well and our thanks go to the UK Coastguard, RAF Kinloss and Grampian Police who provided tremendous support to BP."