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.