Following the 22 October 2012 crash, the major North Sea Super Puma operators, CHC Helicopter, Bond Offshore Helicopters and Bristow Helicopters decided to ground all AS332 and EC225 Super Puma helicopters. On 25 October 2012 it was announced that the problem was suspected to relate to the main gearbox vertical shaft; the AS 332 L1 and L2 versions of the Super Puma could be refitted with an older design, allowing them to resume flying. On 8 November 2012 some Super Pumas of Bond Offshore Helicopters returned to flight. The EC225 grounding continued into 2013, following the validation of new safety measures by the EASA, the type was progressively returned to service following modifications. By mid-2015, all 49 EC225s operating in the North Sea fleets in the UK had been retrofitted with a redesigned bevel wheel vertical shaft to avoid any recurrence.