Search: Helicopter crash investigation
An initial report into the North Sea helicopter crash in which 16 people died has found the aircraft suffered a "catastrophic failure" in part of its main gearbox.
The Air Accidents Investigation Branch (AAIB) found the failure caused the Super Puma's main rotor to detach and its tail to become severed from the fuselage.
There was also a rupture in the helicopter's right-hand engine casing, accident investigators said.
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 on April 1.
A memorial service for the men will be held in Aberdeen next week.
Gearbox failure would have given the crew little chance to save themselves or their passengers, said aviation expert David Learmount, of Flight International magazine.
The helicopter would have "dropped out of the sky like a stone". He said this type of failure was "pretty rare" and there was less than one a year worldwide.
The AAIB report recommends the helicopter's manufacturers, Eurocopter, carry out "additional inspections" of the rotor gearboxes of all AS332L2 models.
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Operators Bond Offshore said the findings confirmed it had been complying with current systems and procedures.
But BP said it would not use the L2 aircraft again until the safety checks were carried out.
