All 18 people aboard a transport helicopter that crashed into the North Sea on Wednesday evening were rescued from the chilly waters, British officials said.

Maritime and Coastguard Agency spokesman Mark Clark said the incident was "on the level of the Hudson River in the States," a reference to the successful splash-landing of a passenger jet into the Hudson River in New York in January.

"They're clearly traumatized and they're cold, but they're walking wounded," Clark told Sky News television. "It's a very successful rescue."

The Super Puma helicopter was taking workers to a British Petroleum-operated oil field 190 kilometres east of the Scottish city of Aberdeen when it crashed at about 6:30 p.m. local time, said company spokesman David Nicholas.

The Royal Air Force's Barry Neilson was involved in the rescue.

"The aircraft that had ditched was sitting upright on the water though the tail boom was missing, and the crew and passengers had managed to evacuate the aircraft very successfully," he said.

"It was very foggy out there, and the first aircraft to arrive on the scene had some difficulty letting down to the surface but succeeded and lifted three [people] out of the dinghy."

Flight Sgt. James Lyne, an assistant controller with the Royal Air Force's search and rescue organization, credited the pilot for the happy ending.

"For the aircraft to remain upright is a remarkable feat by the pilot, and undoubtedly that's what saved all those lives," he said.

The two crew and 16 passengers then made their way from the helicopter on to three rubber dinghies. Locator beacons aboard the vessels alerted rescuers to their position, Lyne said.

Scottish First Minister Alex Salmond said the rescue "averted what could have been a terrible tragedy."

The coast guard said the helicopter was owned by Bond Offshore Helicopters Ltd., which provides air transport for energy installations.

Helicopters are frequently used to ferry workers to and from oil and gas rigs in the North Sea.

Jake Molloy, an official with the Rail, Maritime, and Transport Workers Union, said there are about 50 flights a day between Aberdeen and the various installations in the area.

The helicopters tended to have a "pretty good record," he said, noting that the last fatal crash occurred more than two years ago.

With files from the Associated Press