Human error was to blame for the helicopter crash in Morecambe Bay in which the two crew and five passengers perished as they tried to land on a gas platform, according to an official investigation.

The Air Accidents Investigation Branch report found that the co-pilot lost control, there was a delay in the commander taking over, and the CHC Scotia helicopter plunged into the sea with the loss of all on board.

The tragedy happened on December 27, 2006 as the helicopter approached North Morecambe platform in poor weather conditions.

"There was no evidence of any technical malfunction that may have contributed to the accident and the investigation therefore sought to understand why two experienced pilots were unable to stop a serviceable helicopter flying into the sea," the report states.

The two crew killed were Steve Potton, 51, chief pilot at Blackpool and commander of the flight, and Simon Foddering, 33, a senior first officer and an experienced pilot.

The passengers were John "Jake" Shaw, 51, from Kirkcaldy, a father of three children and two stepchildren; Les Ahmed, 48, from South Shields; Alf Neasham, 57, from Durham; Bob Warburton, 60, from Heysham; and Keith Smith, 57, from Stockton-on-Tees, whose body has never been recovered.

As the helicopter approached the platform Mr Potton asked Mr Foddering: "You all right?" as the helicopter started to pitch.

He replied: "No, I'm not happy mate."

A request for help was not initially understood by the commander and there was a four-second delay before he took control, the report said.