Bristow Helicopters, the British civil helicopter operator which handles transportation of oil workers in Nigeria, has been involved in another air mishap, Nigerian aviation sources said on Wednesday, five months after another of its plane plunged into the lagoon, killing six people, including the pilot and co-pilot.

On 12 August last year, the Bristow Sikosky S76 C+ helicopter crashed into the Lagos lagoon, trapping the occupants deep in the water and killing six of them. Six others survived.

Bristow Helicopters is a British civil helicopter operator originally based at Aberdeen Airport, Scotland which is now part of the U.S. based Bristow Group.

Details about the latest mishap were still sketchy and the Accident Investigation Bureau could not be reached. But aviation sources said the helicopter from Port Harcourt to Lagos landed on water with 13 people on board.

It was said to be an emergency landing known in aviation circle. It was not clear if anyone was hurt.

Simonateba.com will update shortly.