ASURVIVOR of the North Sea helicopter crash that killed four oil workers has demanded answers over what went wrong on the fateful day.

James Nugent, 41, from Newquay, who suffered spinal injuries in the accident, spoke out as a memorial service for those who were killed was held in Aberdeen yesterday.

The accident on August 23 involved a Super Puma L2 helicopter which was transporting workers from Borgsten Dolphin Oil platform to Sumburgh Airport in Shetland.

After a major power loss, the aircraft, which was carrying 16 passengers and two pilots, plummeted into the North Sea.

Two lifeboats, coastguard helicopters, RAF planes and a ferry were involved in the rescue operation. Casualties were flown by air ambulance to nearby hospital in Lerwick.

Nugent, who is from South Africa, is asking for an explanation after safety concerns were raised about the use of the vehicles to transport workers.

He said: "There is obviously a need to fully understand what happened in this awful incident.

"It was so tragic and simply no-one deserves to die whilst being transported home from work.

"Like myself, we all just wanted to get home to our families after a long time working offshore.

"The accident has destroyed my short-lived career working offshore and the same for others that were also in the accident.

"I just want answers over what has happened and for someone to take responsibility for the fact that 16 passengers and two pilots were in a horrific aviation accident that should never have happened."

The Air Accidents Investigation Branch said it found no evidence of technical failure in the helicopter. The 33-strong Super Puma fleet serving the area was grounded following the crash but resumed operations after a week.

Four other accidents involving Super Puma helicopters have happened over the last five years, including a crash in April 2009 which killed 16 workers and two pilots when the gearbox failed.

An investigative report published earlier this month called for a review of local coastguard services after delays were found with one of the rescue boats attending the site of the August crash.

It was found that some rescuers using a Fast Rescue Craft were delayed from getting to the scene due to tidal conditions preventing the craft from leaving the slipway.

Duncan Munro, 46, from Bishop Auckland in County Durham, and George Allison, 57, from Winchester, Hampshire, were killed as they returned from the Borgsten Dolphin support vessel to Sumburgh Airport.

The crash also claimed the lives of Sarah Darnley, 45, from Elgin and Gary McCrossan, 59, from Inverness.

Friends and relatives of the four victims were joined by industry representatives at a memorial service held in the centre of Aberdeen yesterday.

A book of remembrance was also opened to mark the 25th anniversary of the Piper Alpha disaster in July 1988, in which 167 oil workers were killed.

A Church of Scotland official said the Kirk of St Nicholas Uniting church was "well-filled" for the service, which was led by Reverend Gordon Craig.

The memorial service in Aberdeen takes place every year, and is dedicated to everyone in the oil and gas industry who has lost their lives offshore in the previous year.

Three other industry workers were also remembered during the service.