Gear box damage hampering helicopter crash investigation

Published on Friday 17 April 2009 13:45

THE damage caused to the gearbox of the North Sea helicopter which crashed with the loss of 16 lives earlier this month is hampering investigators trying to pinpoint the exact cause of the accident, it was revealed today.

The Air Accidents Investigation Branch (AAIB) has already said the main gearbox of the Super Puma suffered a catastrophic failure as it carried oil workers back to Aberdeen on April 1.

Today, the AAIB said further work was needed to find out just what caused the gearbox failure, as metal debris had been carried through the gearbox, bursting it apart.

It added that this had resulted in a large amount of secondary damage to all gearbox components which was "potentially masking the initial failure".

The 14 passengers and two crew were returning from BP's Miller platform when the helicopter crashed in the sea, 11 miles north east of Peterhead, Aberdeenshire.

Earlier this week, the Prince of Wales, Prime Minister Gordon Brown and Scottish First Minister Alex Salmond were among those attending a memorial service for the victims in Aberdeen.

The AAIB said today: "Examination of the wreckage had identified that the accident occurred following a catastrophic failure of the main rotor gearbox within the epicyclic module, leading to main rotor detachment.

"Detailed examination of the components and fragments of components of the epicyclic module has progressed throughout the Easter weekend. The sequence of failure is now better understood but further work is required to determine the initiating event."

The AAIB went on: "This painstaking work continues as the final failure of the gearbox involved the transport of metal debris through the meshing gears and bearings, absorbing energy from the engines and the rotor assembly, leading to the gearbox bursting.

"This has resulted in a large amount of secondary damage to all gearbox components, potentially masking the initial failure."