A doomed helicopter gave off a "strange loud noise" as it took off for its final flight, a witness told an inquest today.

Ten men - including two from the North-East - died when the Sikorsky S76A crashed into the North Sea three years ago.

The tragic flight was ferrying gas rig workers between off shore platforms when it went down on July 16, 2002.

Among the dead were Stuart Coggon, 45, and Douglas Learwood, 40, who were both from Middlesborough.

Mr Learwood, of Rushmere, Marton, , was an instrument technician for Shell Oils. He had taken a last -minute chance to join his young family on Teesside when he boarded the ill-fated flight.

Mr Coggon, of Clevegate, Nunthorpe, was a draughtsman who worked for AMEC.

The inquest in Gorleston, Norfolk, finally began into their deaths.

The jury inquest heard that the Sikorsky S 76 A operated by Norfolk company Bristow Helicopters had taken off from Norwich International Airport and crashed shortly after 7.40pm just before reaching the Santa Fe Monarch platform.

Consultant aviation pathologist Dr Ian Hill said the men whose bodies have been recovered had suffered extensive injuries. He gave the cause of their deaths as multiple injuries due to an aircraft accident.

The inquest also heard from a witness who described hearing a ''strange, loud noise'' from a helicopter taking off from the airport on the evening of the accident.

Patsy Cook, from Norwich, was in the garden of her home close to the airport when she became aware of the noise.

In a statement to police she said: ''One of my first thoughts was the dreadful noise it was making.'' She described the aircraft as having ''an underlying noise which made me think something was wrong''.

But David Middleton, a licensed aircraft engineer for Bristow Helicopters, carried out a routine inspection of the helicopter on the afternoon of July 16 which gave no cause for concern.

He said in a statement: ''Everything was in order and working correctly.'' Mr Middleton watched the crew carry out a visual check of the helicopter before going through the start-up procedure with them. He then watched it taxi away and take off.

''Nothing gave me cause for concern. It sounded and looked just as it should,'' he said.

Inspector Michael Lamb of Norfolk Police told the inquest that the helicopter ''suffered a catastrophic mechanical failure and crashed into the North Sea''.

He said the investigation into the crash centred on the separation of one of the main rotor blades.

A subsequent report into the crash by the Air Accidents Investigation Branch (AAIB) concluded the helicopter crashed after a failure of one of its main rotor blades.

As well as the two Middlesbrough men the following also died: captain Philip Wake, 42, from Strumpshaw, near Norwich, first officer Philip Dearden, 32, from Norwich, Angus Macarthur, 38, from Maryburgh, Highland, Scotland, Kevin Taylor, 50, from Little Plumstead, near Norwich, Dennis Kelleher, 40, from Lytham St Annes, Lancashire, from Middlesborough, Geoffrey Bispham, 51, from Worstead, Norfolk, and David Graves, 33, from Ilketshall St Andrew, near Beccles, Suffolk.

The body of another passenger, Paul Francis, 48, from Norwich, has not been recovered.

Mr Lamb said that four bodies were recovered immediately by vessels at the scene. One more was recovered a short time later and five others were recovered on July 19. The body of Paul Francis has yet to be recovered. He said it was ''beyond all reasonable doubt'' that Mr Francis was on the flight. The inquest is expected to last three days.