A helicopter could have plunged into the North Sea because of a fault with its tail rotor, an investigation has found.

The pilot of the Sikorsky S92 lost control of the aircraft during a landing on the West Franklin platform in December 2016.

It dragged to the right after a heavy descent, rolled to the left and spun 180 degrees before stopping near the helideck's edge, gouging a hole in the deck in the process.

A report by the Air Accident Investigations Branch (AAIB) said that if the loss of control had happened sooner, the helicopter would have probably ended up in the water.

It said: "If the loss of yaw control had occurred at an earlier stage of the flight, the helicopter would most likely have made an uncontrolled descent into the North Sea."

The incident happened 150 miles east of Aberdeen after a five-minute flight from the Elgin platform. A failed rotor bearing is believed to have been responsible.

Helicopter operator CHC said it welcomed the AAIB's findings in a statement released on Thursday.

"Immediately after the accident, we introduced a number of measures to strengthen the detection of impending degradation," a spokesman said.

"We are confident that the measures we have taken and the actions directed by the Sikorsky since the accident to all operators worldwide will strengthen both our procedures and our compliance monitoring continue to underpin the safety and airworthiness of the Sikorsky S92."