Two helicopters ferrying North Sea oil workers had to return to shore for tests after warning lights came on in separate incidents.

The aircraft, operated by Bond and CHC Scotia, are the same model as the Eurocopter AS332L2 Super Puma that crashed in the North Sea in 2009 killing all 16 people on board.

The Bond helicopter was carrying 16 passengers from the Borgholm Dolphin platform and two crew on Wednesday when an oil pressure light came on.

It dropped 1000ft as a precaution and was escorted to Aberdeen Airport by a CHC helicopter.

A spokeswoman said: "Bond Offshore Helicopters can confirm one of its AS332L2 aircraft landed safely at Aberdeen with all passengers and crew dis-embarking normally.

"Emergency services were in attendance as a precautionary measure, following notification that the crew had observed a standby pump warning light while en route.

"Engineers will examine the aircraft fully before it returns to service."

Later, a CHC Scotia Super Puma carrying 15 workers to the Elgin field and two crew, also had to return to shore when a warning light came on in the cockpit.

A spokesman for CHC Helicopters said: "An AS332L2 flight, travelling to the Elgin field, made a non-emergency return to base after an indicator light came on.

"The aircraft landed safely at Aberdeen heliport, and will be inspected by engineers."

The Super Puma EC225 fleet was grounded for a while after an incident in October when a problem with a Super Puma's gearbox caused it to ditch in the sea off Shetland.

The 17 passengers and two crew were rescued.

In May, all 14 passengers and crew members on a Super Puma were rescued after it ditched 30 miles off the coast of Aberdeen.