The military has cancelled all training flights involving Cormorant helicopters after a fatal crash early Thursday that killed three crew-members.

However, the fleet has not been grounded entirely, and the helicopters will still be used when necessary, said Lt.-Col. Tom Hughes, commander of 413 Transport and Rescue Squadron.

The fatal crash occurred at about 12:30 a.m. off the coast of eastern Nova Scotia near Canso.

The four surviving crew members were rescued and taken to hospital. Two were airlifted to hospital in Halifax with serious but non-life threatening injuries, while the other two were taken to Canso.

A visibly upset Hughes spoke at a news conference at 14-Wing Greenwood Thursday morning.

"The Cormorant fleet has not been grounded, but we are going to use them on a restrictive basis for essential (search and rescue) operations only," he said.

"We are still operational and when a rescue is required we'll go out and save lives when it's needed. We don't say training flights are grounded we just say at the moment we're not going to undertake training flights."

Lt.-Col. Steve Brabant, acting commander of 14-Wing Greenwood, described the move as an "operational pause," until the full investigation is complete.

He said the military still has confidence in the CH-149 Cormorant aircraft, but will await the results of the investigation into the crash before full operations are resumed.

While the Cormorant helicopters initially had some problems with their tail rotors, Brabant said there was no indication that that was the cause of the crash.

"Of late they (the tail rotors) have been doing quite well.  We had not seen any problems with them in quite some time," he told ATV News.

The military has released the names of the crew members who were involved in the crash.

The men who were killed were Sgt. Duane Brazil, 39, Master-Cpl. Kirk Bradley Noel, 33, and  Cpl. Trevor Sterling McDavid, 31, said a spokesman from 14-Wing public affairs.

Brazil was from Gander, N.L., and was married with two daughters, Noel was from St. Anthony, N.L. and was single, and McDavid, who was originally from Sudbury, Ont. was married with two daughters.

The injured crew members are Capt. Gabriel Simon Ringuette, 41, Sgt. Martin Francis Moloney, 48, Capt. Ronald Earl Busch, 40, and Major Gordon Clements Ireland, 42.

Ireland was born in Northern Ireland, while the other survivors are originally from Ontario.

Hughes said few details are known at this point about the cause of the crash. He said the crew was performing a training operation where members are lowered from the helicopter to the deck of the Coast Guard vessel the Four Sisters, then hoisted back up.

"We do it frequently. It's one of our bread and butter missions to go and hoist people off of boats in darkness, and so it's something we train for on a regular basis."

The wreckage of the helicopter, as well as the bodies of three crew members who died when it went down, have been recovered.

Eyewitness saw the helicopter go down

An eyewitness who was aboard the Four Sisters told The Canadian Press the crash happened before anyone had time to react.

"They veered to the right of the boat, the nose tipped a little bit and she crashed in the water,'' he told CP. "It was so fast that nobody would have had a chance to even remotely say anything.''

But the crew reacted quickly after the crash, bringing sleeping bags, blankets and jackets to keep the survivors warm.

"Some of them were pretty cold and shaking and starting to go into shock,'' Bond said.

"We did everything that we could do with the little bit of training that we did get, that we did know, that we could think of at the time.''

In his interview with ATV, Brabant offered "a very heartfelt thank you" to the civillians who assisted in the rescue.

PM offers condolences

Prime Minister Stephen Harper issued a statement Thursday expressing his condolences.

"It is with great sorrow that I learned of the tragic search and rescue training accident this morning that took the lives of three brave Canadian Forces members and injured four of their crew mates," Harper said in the statement.

"My thoughts and prayers are with their family, friends and loved ones during this difficult time. It is my hope that they find some solace in the knowledge that they do no grieve alone. Canada mourns the loss of these men."

Military investigators will comb through the wreckage when it arrives in Canso, military spokesman Capt. John Pulchny told CTV Newsnet.

On Thursday morning the weather in the area was windy and rainy, but Pulchny said it is not yet known if conditions played a factor in the crash.

"At that time it apparently was not favourable conditions but still good enough to do a training mission," he said.

Questions about the safety of Cormorant fleet

The Italian-made Cormorant helicopters are a relatively new addition to Canada's search and rescue fleet.

Fifteen of them were brought in to replace the 1960s-era Labrador helicopters in the late 1990s.

They have had some problems since they were put into active duty.

In October 2004 the choppers were grounded after cracks were discovered on a tail rotor.

At the time, the military said that if the cracks spread they could cause the blade to come off.

And in February of the same year two of the helicopters developed fuel leaks, and mechanical problems were reported in the hoist systems.

The fleet of 15 choppers cost Canada $779 million.

With files from The Canadian Press