09/25/2013 08:30 EDT | Updated 11/25/2013 05:12 EST

Arctic helicopter crash details emerge

Only one of the three men who died in the Arctic crash of a Canadian Coast Guard helicopter was wearing a full immersion suit, which was not completely zipped up, and only one victim had a life jacket on, CBC News chief correspondent Peter Mansbridge reported Wednesday.

Sources close to the crash investigation have helped CBC News piece together some of what happened on the helicopter's fateful mission.

- Crashed Arctic helicopter found

Marc Thibault, the commanding officer of the coast guard ship Amundsen, Daniel Dubé, the pilot of the helicopter, and Klaus Hochheim, an Arctic scientist affiliated with the University of Manitoba, died of hypothermia on Sept. 9 when their chopper crashed into the Arctic Ocean. The crash occurred in M'Clure Strait, about 600 kilometres west of Resolute, while the three men had been on an ice research flight.

CBC News chief correspondent

All three men managed to get out of the chopper before it sank, but then the water, which was about 0 C, began taking its icy death grip.

Full immersion suits are designed to protect the wearer from cold water, but only if they are fully zipped up. Dubé’s body was found with the suit only partially zipped up. Pilots often fly with the suits partly open because they get warm.

Thibeault and Hochheim both had different suits on, but not the kind that would provide full protection against the icy waters.

David Barber, a veteran of Arctic research and a friend of Hochheim, recognizes the crew was alive for only a brief time in the water.

"The water’s far too cold and…you go through all the stages of hypothermia very rapidly with death following shortly thereafter because your internal organs all shut down," he said.

Additionally, two of the men were found in the water without life jackets, and while the third man did have one on it was not properly inflated. Coast guard policy is that life jackets must always be worn on helicopter flights over water.

Prior to the crash, the crew had been working about five kilometres from the Amundsen, and had radioed to the ship that they were returning. But the evidence, in addition to the survival suits and life-jackets, suggests whatever happened to the chopper occurred quickly:

- Dubé had no time or was unable to send a final radio distress call.

- Pictures of the aircraft taken more than 400 metres down on the sea floor show the chopper’s front section heavily damaged and the tail broken off.

- There is said to be a debris field about 300 metres around the aircraft.

- The helicopter had equipment that could have kept it afloat for hours, but pictures indicate that while the switch for the pop-up floats was activated, they were not deployed.

- The aircraft carried a life raft for emergencies, but there’s no evidence it was used.

The wreckage of the helicopter was raised to the surface on Wednesday. Crash investigators will now begin trying to determine why the chopper went down, but that could take a year or more, and it won’t be easy. The helicopter did not carry flight data recorders. While it did carry a fixed camera to record the ice probe operation, it is not clear if it was recording at the time things went terribly wrong.