Last year, two helicopters ditched in the North Sea only six months apart. All passengers and crew were rescued in both incidents which were found to be caused by gearbox problems.
In October, 17 passengers and two crew were rescued from life rafts by a passing vessel after the helicopter, which was carrying an oil crew from Aberdeen to a rig 86 miles north-west of Shetland, was forced to ditch.
Previously, in May 2012 all 14 passengers and crew members on a Super Puma helicopter were rescued after it ditched about 30 miles off the coast of Aberdeen.
The helicopter was on a scheduled flight from Aberdeen airport to a platform in the North Sea at the time.
Super Puma EC 225s were grounded in the wake of the two incidents but were given approval to fly again and services resumed earlier this month.
In April 2009, 16 people died when a Super Puma plunged into the sea. Its gearbox failed while carrying the men to Aberdeen.
The Bond-operated aircraft was returning from the BP Miller platform when it went down off the Aberdeenshire coast.