A HELICOPTER carrying oil workers was grounded on a North Sea ship overnight when a fuel leak was found.

The Bristow S-92 landed on Alba Floating Storage Unit (FSU) on May 28 and was prevented from returning to the mainland the same day after the "technical issue" was discovered.

The aircraft was carrying seven passengers and two crew when it landed at 5pm for a staff switch.

A series of measures aimed at improving offshore helicopter safety were announced by the Civil ­Aviation Authority in the wake of a fatal Super Puma crash last year.

A source who works on the FSU, which operates in an oil field 130 miles north-east of Aberdeen, said that when the helicopter came in the fault was noted and an engineer was deployed to fix the problem.

He said: "It was leaking badly when it was on the ground and there was no thrust, so even more fuel would have come out if it was airborne.

"If it wasn't noticed when it was landed, that helicopter would have gone down, no question."

A spokeswoman for oil giant Chevron, which runs the FSU, said: "A helicopter was temporarily retained on the Alba FSU platform as a precautionary measure as a result of a technical issue which has been resolved."

Bristow Helicopters confirmed one of its S-92 models was shut down on the offshore installation "as a precautionary measure".

A spokeswoman said: "Following functional tests and in consultations with the Aircraft Manufacturers and Regulatory Authorities, the aircraft was declared serviceable and cleared to complete its scheduled return flight to Aberdeen."