The North Sea helicopter crash which killed 14 oil workers, and two crew members, back on April 1 could have been prevented, according to investigators.
It appears that flight 85N was doomed well before the 16 men on board the Super Puma aircraft knew anything about it.
The U.K. Air Accidents Investigation Board (AAIB) said that a flake of metal in the main rotor gearbox was identified by a detection system, but that it failed to set off any warning alarms to inform the crew. Following the enquiry the body has now called upon the European Aviation Safety Agency (EASA) and companies operating the Puma crafts to review the design, operational life and inspection processes of the gears.
To compound the failure of operating procedures – be they human or machine – a metal chip was found in the gearbox a week, and some 34 flying hours, before the fatal incident, but engineers concluded that the particle was of a type that did not require further investigation.
The appearance of such debris should be treated as a sign of possible future gearbox failure.
The helicopter was returning back to the mainland, to Aberdeen, from BP’s Miller platform in the North Sea at the time of the incident. The initial report into the crash disclosed that the gearbox of the aircraft had suffered a “catastrophic failure” before plummeting into the sea 9.3 miles off of the coast of Peterhead, Scotland. The black box recorded on board the helicopter revealed a warning of low oil pressure in the gearbox and a subsequent drop.
The latest AAIB report stated: “Had a different diagnosis of the chip type been made on March 25, it is possible that the main rotor gearbox (MRG) would have been removed from service for further investigation.”
The manufacturers of the Super Puma aircrafts, Eurocopter, have since issued guidelines to help operators work out the significance of metal fragments that may be found in gearboxes, in future.
“We welcome the latest recommendations from the AAIB and the action by the manufacturer which will further enhance measures ensuring the safety of helicopter operations,” said Bill Munroe, Managing Director of Bond Offshore Helicopters – which includes the Super Puma as part of their operating fleet.
The Crown office has said that the procurator fiscal’s investigation into the circumstances of the disaster remains ongoing.