The search for 16 people missing in the icy North Atlantic waters off Newfoundland following the crash of a helicopter continues into the night as the odds for rescue grow fainter by the hour.

One person survived the Thursday morning crash, while one body was recovered.

The chopper, which was carrying offshore oil workers, went down about 65 kilometres southeast of St. John's, at about 9:18 a.m. local time.

Maj. Dennis McGuire of the Joint Rescue Co-ordination Centre, said two life rafts had been recovered, but there were no survivors in either raft. They can be deployed manually or automatically from the helicopter.

Rescuers acknowledged the prognosis appears to be grim.

McGuire said at a Thursday evening news conference that rescuers have not picked up any signals from the emergency beacons attached to the survival suits of those on board.

"I can't speculate on why they wouldn't have worked," he said.

He said weather continues to get worse, hampering rescue efforts. A 30-year old male has an estimated "survivability" of 30 hours at sea, when wearing an exposure suit, which all passengers and crew were wearing.

"We will continue to search until there is no chance that any survivors may be located," McGuire said.

Four coast guard ships as well as several military helicopters and a plane are involved in the search.

The chopper crashed and sank in 140 metres of water, and left a debris trail of about six kilometres.

The survivor has been identified as Robert Decker of St. John's, who is being treated in a local hospital. He is listed in critical condition but was awake and moving while being transported.

His family is with him, McGuire said.

The name of the deceased had not been released.

Crash details

The helicopter was en route from St. John's to the Hibernia platform when the pilot reported mechanical troubles and turned back towards St. John's. The chopper issued a distress call and eight minutes later, went into the water.

"Mechanical problems were reported and we don't know of what nature," said Julie Leroux, spokesperson for the Transportation Safety Board.

It is believed that the pilot was "ditching" the aircraft, that is, making an attempt to intentional crash-landing the aircraft due to the mechanical problem.

The crew of a Provincial Airlines plane flew over the area within a few minutes of the crash and reported that the helicopter was floating upside down. The helicopter sunk shortly afterwards.

The missing aircraft is an S-92 Sikorski operated by Cougar Helicopters in St. John's.

Rick Burt, the general manger of Cougar Helicopters, said the helicopter was no older than four years old.

He said his "thoughts and prayers" are with the families of those on board.

"We have only one person at this time," he said at news conference Thursday. "This is a very difficult time for Cougar, our colleagues, our customers and our families."

"I've been here 30 years. ... Most of these people are my friends and I've flown with them," he added, in a barely audible whisper.

Premier Danny Williams issued a statement, saying it was "with a heavy heart" that he learned of the news.

"I want to express my most heartfelt and sincere condolences to the family and friends of the individual who has been confirmed lost," he said.

"I cannot begin to imagine the sorrow and despair of those who are left to mourn this incredible tragedy."

Early rescue efforts

Jeri Grychowski, spokeswoman for the Rescue Co-ordination Centre in Halifax, said the massive rescue effort was launched after the initial mayday call came in at 9:15 a.m. local time to air traffic controllers in Gander, N.L.

A supply ship from St. John's was first on the scene.

Waves are between two and three metres in the area, and winds are roughly 37 kilometres per hour, Grychowski said.