Inquiry finds proper maintenance might have prevented 2009 North Sea helicopter disaster

Sunday, March 16, 2014

The helicopter involved, photographed in 2004 shortly after Eurocopter delivered it to Bond.
Image: Gary Watt.

A Fatal Accident Inquiry (FAI) ruled on Thursday a helicopter crash into the North Sea might have been prevented had proper maintenance procedures been followed. All sixteen on board died when the aircraft went down off the Scottish coast.

After a hearing in Aberdeen, Sheriff Principal Derek Pyle found Bond Offshore Helicopters failed to remove a component after a metal shard was found. The shard suggested spalling, or the shedding of metal particles in the aircraft's gearbox. "The size and shape of the particle found [...] were consistent with an advanced stage of classic spalling" according to the inquiry's findings.

A week before the crash Bond mulled partially replacing the gearbox. The aircraft went down after the gearbox failed in flight. Pyle found a failure in communication between Bond and helicopter manufacturer Eurocopter had led to the decision not to replace the gearbox.

The routine flight was taking oil workers back to Aberdeen from the Miller offshore oil platform, owned by BP. The aircraft radioed air traffic control to inform they were twenty minutes from Aberdeen Airport but six seconds later was confronted with an oil warning light and grinding sounds. The crew declared an emergency but the main rotor broke free, which in turn smashed through the tail leaving the aircraft to plunge into the sea. The aircraft crashed within twenty seconds of the first sign of trouble.

The inquiry is surrounded by controversy owing to the five-year gap between accident and findings, and the decision by Crown Office not to prosecute over the crash. "For a criminal prosecution to have taken place, the Crown would have to prove its case beyond reasonable doubt" a Crown Office statement said on Thursday. "The Sheriff Principal makes clear that a reasonable doubt remained over the technical cause of the crash".

Although the Air Accidents Investigation Branch (AAIB) and Sheriff Pyle found a catastrophic gearbox failure triggered the crash, the exact cause of the failure was never conclusively decided. After hearing expert evidence Pyle found the balance of probabilities pointed to spalling, but could not rule out a manufacturing defect.

The inquiry's findings note "that it would be an extraordinary coincidence if the failure properly to carry out inspection and maintenance of the helicopter’s gearbox was not causative of a catastrophic failure of the same within a matter of days. But, as the evidence made clear, such a coincidence was indeed a possibility." Pyle's report added "the small piece of the helicopter which would have proved the matter beyond any doubt [has] not been recovered from the seabed".

We have always accepted that we made mistakes through honest confusion over telephone calls and emails

—Bond Offshore Helicopters

Bond have released a statement noting "We have always accepted that we made mistakes through honest confusion over telephone calls and emails." Sheriff Pyle found Bond's employees "tried to carry out their jobs as diligently as they could. All of them impressed me as engineers who well understood the vital importance of their role in ensuring [...] safety". He also found staff were well-trained and resourced, echoing findings by the AAIB and the Civil Aviation Authority.

Pyle noted Bond readily accepted they should have properly followed the maintenance manual and normally did, but "on one occasion, that fundamental rule was broken" and the crash was likely a result. Bond, Eurocopter, and investigators all gave evidence.

Trade unions and victims' families, however, have slammed the decision not to prosecute. While welcoming the FAI's conclusions, victims' lawyer Tom Marshall said the families wanted to review the decision not to prosecute with the Lord Advocate, and are also seeking a broader public inquiry. Audrey Wood, whose son Stuart died in the disaster, said "How [Crown Office] arrived at that decision [not prosecuting] will haunt us, as not only did we hear of multiple breaches of health and safety, but the decision was also made without all the evidence being present, as vital witness statements had not been given".

Wood said there were multiple breaches of health and safety law that could be prosecuted. Crown Office's statement counters "evidence presented during the FAI has not altered the insufficiency of evidence, therefore the decision not to hold criminal proceedings remains the correct one". Unite union branded their decision a "travesty of justice".

File photo of the buildings of the Scottish Parliament, in Edinburgh, where Labour have taken the debate on FAI delays by introducing a bill.
Image: David Monniaux.

Politicians have criticised the five-year delay holding the FAI, as has Scottish Trades Union Congress general secretary Grahame Smith who said "It is vitally important that lessons are learned at the earliest opportunity following tragedies where lives are lost". Sheriff Pyle himself concluded "what can, I think, very properly be said is that nearly five years [delay] is on any view far too long and that we all have a responsibility for that. [...] everyone concerned in future fatal accidents involving aircraft of whatever kind should do much better."

Labour have called for new FAI rules; MSP Patricia Ferguson has put a bill before parliament; the Scottish Government says Sheriff Pyle's conclusions are being scrutinised. MSP Richard Baker said the victims' families and North Sea oil workers, who routinely use helicopters, had waited "far too long" for the FAI to conclude. "FAIs should never be delayed so long again."

Crown Office expressed sympathy with the families involved for the delay but blamed the complex nature of the investigation, and pointed out the AAIB, Civil Aviation Authority, and local police had all already conducted their own enquiries. The AAIB spent 30 months investigating.

Twelve victims were from Scotland, many of those from in and around Aberdeen where the six-week inquiry was held. Three more were from elsewhere in the UK and the last was a Latvian national. Half of the fourteen passengers and two crew died "instantaneously" and the rest died very shortly after impact with the sea from blunt force trauma, the inquiry found.

None survived long enough to drown, according to Sheriff Pyle. Nonetheless he noted "there was a poignant moment when a witness was being taken through the graph in the AAIB report which set out the timeline of the accident that I, if not others present, understood for the first time the true horror of what took place."

Audrey Wood said "The length of wait for nearly five years has been intolerable for all the families and we, the families, feel let down by the system." Bond's statement this week says "We would like to express again our deep sorrow at the 16 lives lost. Bond Offshore hopes [the inquiry] brings a degree of closure to the families, friends and dependents of those who died in the tragedy of 2009." The sheriff also noted the "courage" of victims' families, who attended the full hearing.

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