NO precautions could have prevented a North Sea helicopter crash which claimed four lives - including a Bishop Auckland man - after a “perfect storm” of circumstances combined, an inquiry has found.

A Fatal Accident Inquiry (FAI) found that all the safety barriers in place did not manage to prevent or remedy the pilot’s “one failure” to maintain the correct speed as it approached Sumburgh Airport in Shetland.

Duncan Munro, 46, from Coundon, near Bishop Auckland, was killed when the Super Puma L2 ditched on its approach to Sumburgh Airport in Shetland at 6.17pm on August 23, 2013.

Mr Munro, an oil rig worker and special constable, was survived by wife Penny and their daughter Katy.

Sarah Darnley, 45, from Elgin, Moray; Gary McCrossan, 59, from Inverness; and George Allison, 57, from Winchester, Hampshire, also died.

Survivor Samuel Bull took his own life in London in 2017, which Sheriff Principal Pyle said was “directly caused” by the crash.

An AAIB report published in 2016 found that the pilots failed to properly monitor the flight instruments and failed to notice their speed was decreasing until it was too late to avoid the helicopter plunging into the sea.

In his determination following the FAI, Sheriff Principal Derek Pyle said the crash happened because the commander failed to maintain the target approach speed of 80 knots.

He wrote: “If he had done so, the helicopter would not have reached the critically low energy state from which recovery was impossible.

“That is where ultimate responsibility rests, but as several witnesses explained there are other safety barriers in place each of which of its own would prevent such a failure either occurring or, if it does occur, quickly and effectively remedying it.”

He said there was “plainly no wilful neglect” on the part of Captain Martin Miglans, describing him as a “pilot of huge experience with a first class record of flying over many years”.

However he said: “Rather, there was, as one witness described it, a perfect storm of circumstances which resulted in all the safety barriers in place not preventing – or remedying – his one failure, to maintain the correct speed.”

In his determination, he said that there were no precautions which could reasonably have been taken that might realistically have resulted in the deaths, or the accident resulting in the deaths, being avoided.

He also praised the “exemplary conduct” of co-pilot Alan Bell, both in the seconds immediately before the crash and in his efforts to save the survivors, “but for which others would almost certainly have died.”

Mr Pyle said much has improved over the last 20 years, and that while helicopter trips in the North Sea are by their nature more perilous than general flights by fixed wing aeroplanes they are a “safe means of transport.”

Improvements include the development of a new helicopter terrain awareness warning system, while it is now compulsory for operators in the UK to provide compressed air breathing systems for commercial offshore helicopters.

During evidence from survivors during the FAI, held virtually in August and September, some described their submersible training and contrasted it with training for the Norwegian sector, which some said was more realistic.

However, Mr Pyle said that a balance has to be struck between realism and the safety of those being trained and that it would be “impractical, perhaps impossible”, to provide realistic training which would ensure that passengers had sufficient experience to make a significant difference.

The Sheriff Principal also commented on the length of time it took for the FAI to start, seven years after the accident, but said the delay was beyond the Crown’s control.