THE brother of a man killed in a North Sea helicopter crash has spoken of his family's "five years of heartache" as he renewed calls for the operator to be prosecuted.

Nolan Goble, 34, from Norwich, was among 16 men who died when a Super Puma, operated by Bond Offshore, crashed into the sea off the Aberdeenshire coast on April 1, 2009.

At an inquest in Norwich, coroner Jacqueline Lake recorded a narrative verdict, saying Mr Goble died of multiple injuries following a helicopter crash.

A fatal accident inquiry held before Sheriff Principal Derek Pyle earlier this year found the tragedy may have been avoided if proper maintenance had been carried out, but the Crown Office said the company would not be prosecuted as failings could not be proved beyond reasonable doubt.

An earlier Air Accidents Investigation Branch probe found the aircraft had a "catastrophic failure" of its main rotor gearbox.

Bob Goble described his brother, who was employed by KCA Deutag Drilling Ltd, as an "amazing, fit, young man", adding: "They knew there was a problem with the helicopter and decided to fly anyway.

"The families are talking to solicitors about what further we can do, but it feels like no might mean no. We have had five years of heartache and still have nobody accepting responsibility is just postponing the agony."

Earlier this year, a Bond Offshore spokesman said it was committed to improving safety. It issued a statement saying: "We have always accepted we made mistakes through honest confusion over phone calls and emails.

"Lessons have been learned and lessons continue to be learned."