Crashed helicopter's gearbox failed
PUBLISHED: 14:23 15 April 2009 | UPDATED: 10:47 07 July 2010
An investigation into the North Sea helicopter crash in which a Wells-raised oil rig worker died has found the aircraft suffered a "catastrophic failure" in its main gearbox.
An investigation into the North Sea helicopter crash in which a Wells-raised oil rig worker died has found the aircraft suffered a “catastrophic failure” in its main gearbox.
Nolan Goble, 34, was among 16 passengers and crew who perished when the Super Puma helicopter plunged into the sea as it returned from a BP drilling platform off the Scottish coast on April 1.
An initial report by the Air Accidents Investigation Branch (AAIB) says the gearbox failure caused the rotor blades to detach from the aircraft, severing the tail boom from the fuselage.
It recommends the helicopter's manufacturer, Eurocopter, implements a regime of additional inspections of the rotor gearboxes of all AS332L2 models, and improves its monitoring and warning systems.
The report says: “Examination of the wreckage indicates that the accident occurred following a catastrophic failure of the main rotor gearbox.
“This resulted in the detachment of the main rotor head from the helicopter and was rapidly followed by main rotor blade strikes on the pylon and tail boom, which became severed from the fuselage.”
Investigators also found one of the engine casings was ruptured, but “investigations were continuing to understand completely the accident sequence”.
The helicopter was operating in “benign” weather conditions when the accident happened.
The report says the daily in-flight checks had been completed satisfactorily and the co-pilot made a routine call to say the helicopter was serviceable - but air traffic controllers picked up a mayday call twelve seconds later.
An eyewitness working on a nearby supply vessel saw the aircraft hit the sea.
The report says: “Immediately after impact he saw the four main rotor blades, still connected at their hub, strike the water.
“Around this time, he also heard two bangs, close together. He immediately raised the alarm and the ship turned towards the accident site, which by now was marked by a rising column of grey then black smoke.”
Trade unions for offshore workers have called for all Super Puma helicopters to be grounded while safety inspections are carried out.
Mr Goble, who was raised in Wells but lived in Norwich, was one of four brothers including former Norwich City footballer Steve Goble.
The Prime Minister, Gordon Brown, was expected to join the Prince of Wales, the Duchess of Cornwall and hundreds of mourners at a memorial service in Aberdeen yesterday to honour the victims of the crash.