A false warning of system failure resulted in the crew of a helicopter ditching in the North Sea, according to a report.
All 14 passengers and crew members on the Super Puma were rescued following the incident on May 10, about 30 miles off the coast of Aberdeen.
Air accident investigators said the crew carried out a controlled ditching after a warning indicated a failure of the main gearbox emergency lubrication system.
The helicopter was on a scheduled flight from Aberdeen Airport to a platform in the North Sea at the time.
It was the first time the emergency lubrication system on the EC225 aircraft had been activated in-service.
However, the Air Accidents Investigation Branch (AAIB) report said the system had given the crew a "false warning".
It said: "The evidence indicates that the emergency lubrication system had activated and remained operating for the remainder of the flight.
"Thus, the system had given the crew a false warning of system failure. This warning resulted in the crew ditching the helicopter in the sea."
Investigators have now recommended a review by the manufacturer to be carried out on the system.
"It is recommended that the European Aviation Safety Agency requires Eurocopter to review the design of the main gearbox lubrication system on the EC225 LP Super Puma to ensure that the system will provide the crew with an accurate indication of its status when activated," the report said.