A Super Puma helicopter made an emergency landing at Aberdeen Airport after a warning light came on.
The incident, which happened on Friday, involved an L2 model of the aircraft, operated by CHC Scotia.
The flight was on its way to the Awilco-owned WilHunter rig, an hour east of Aberdeen, with 16 passengers and two crew on board. The pilot turned back and landed the aircraft safely at Aberdeen Airport at 2.30pm.
The passengers were later flown off in another helicopter, while engineers examined the first craft.
A fortnight ago, two L2 Super Pumas, heading to different North Sea installations, turned back to shore following concerns.
It is understood passengers onboard the Bond-operated flights reported unusual noises and alerted the pilots who chose to return to base.
It was soon discovered there were no problems with either craft. The EC225 model of the Super Puma has been grounded since October following the second ditching in the North Sea this year.
Seventeen oil workers and two crew were rescued after the CHC-operated flight had to land on the sea en route from Aberdeento a rig 86 miles off Shetland. Eurocopter, which manufactures the Super Puma fleet, believes the October ditching was almost identical to one involving a Bond helicopter in May.
An initial bulletin, issued by the Air Accident Investigation Branch, reported a crack in the main gear shaft had been discovered after the helicopter carried out a controlled ditching.
A warning light indicated a failure of the main gearbox lubrication system and triggered the crew’s response.
Eurocopter believes the warning light was set off in error – as happened at the time of the ditching of the Bond helicopter in May.
In both incidents all passengers and crew managed to escape safely. The EC225 model is not expected to fly again until February.
Jake Molloy of the RMT union said: “We have seen with the two recent ditchings that it is the requirement to land the aircraft safely, even if the alerts are false.”