13/05/2012 08:34 BST

Gearbox Fault Grounds Helicopters

The owners of a helicopter which ditched in the North Sea last week grounded more aircraft today after an early investigation revealed a fault in its gearbox.

Bond Offshore Helicopters said it was extending its suspension of Eurocopter Super Puma helicopters from the EC225 model which ditched 25 miles off the coast of Aberdeen on Thursday to also include the AS332L2 model.

The move comes after an initial Air Accidents Investigation Branch examination of the EC225 which went down while carrying 12 passengers and two crew showed it suffered a crack to a gearbox shaft.

"In the light of the AAIB interim Service Bulletin Bond Offshore Helicopters Ltd will continue the flight suspension of the EC225 and now in addition the AS332L2 helicopter," a spokesman said.

"Bond Offshore Helicopters Ltd is working with Eurocopter as a matter of priority in finding a solution that will enable the helicopters to be returned to service."

A gearbox failure was responsible the downing of a AS332L2 Super Puma helicopter flying to Aberdeen from the Miller Platform in the North Sea in April 2009, causing the death of 14 offshore workers and two crewmen.

In a report in 2009 into the crash, the AAIB said the gearbox of the Eurocopter had suffered a "catastrophic failure" before it crashed into the sea.

Bond, which suspended all EC225 flights last week while it investigates what happened, said the AAIB analysis of last week's incident matched its own.

The AAIB report into the latest crash says: "The crew of the helicopter carried out a controlled ditching following indications of a failure of the main gearbox (MGB) lubrication system and, subsequently, a warning indicating failure of the emergency lubrication system.

"The investigation has identified a 360° circumferential crack in the bevel gear vertical shaft in the main gearbox, in the vicinity of a manufacturing weld, causing disengagement of the drive to both mechanical oil pumps."

All those on board the helicopter arrived safely back on land after air and sea rescues last Thursday.

A major rescue operation was launched after the alarm was raised, with Coastguard and RAF helicopters called to the scene along with two lifeboats.

The 12 passengers and two crew members were recovered from the sea and put into life rafts.

Nine men were flown to Aberdeen Royal Infirmary while the remaining five were taken to Aberdeen by lifeboat.

Bill Munro, the firm's managing director, added: "The skill and training of Bond's pilots has been witnessed at first hand. Our passengers can be confident in Bond as the principal crew change operator in the North Sea."