ST. JOHN'S, N.L. - Preliminary indications suggest that Cougar Flight 491 slammed into the North Atlantic nose down, the lead investigator into the helicopter crash that killed 17 said Thursday.

One week after the tragic accident, officials with the Transportation Safety Board began examining the battered fuselage of the helicopter in an effort to determine what caused the aircraft to plunge so quickly.

"I would suspect that it was basically nose down," the federal agency's Mike Cunningham said in an interview.

"It's in terrible shape," Cunningham said of the fuselage, currently stored at an airport hangar in St. John's. "There's a lot of jagged metal."

The flight data and cockpit voice recorders were recovered from the Sikorsky S-92A on Tuesday, but Cunningham said investigators haven't had an opportunity to review the information they contain -- data that could be vital in explaining what prompted the chopper's abrupt descent into icy seas, 65 kilometres southeast of St. John's.

Most of those who died in last Thursday's crash were found strapped into their seats, Cunningham said.

"The event occurred so quickly, that really you can't even consider it to be a normal type of evacuation or egress," he said.

"It was basically just a sudden impact with the water."

About 80 per cent of the wreckage has been recovered so far. The Atlantic Osprey offshore supply vessel returned to the crash site Thursday to recover the rest, including the tail rotor assembly.

The lone survivor, 27-year-old Robert Decker, has been recovering in a St. John's hospital from lung injuries and fractures since the crash.

Cunningham said he couldn't explain how Decker and the body of Allison Maher had escaped the helicopter while the 16 others remained inside.

RCMP Sgt. Wayne Newell said police have not yet been able to speak with Decker to get his recollection of events.

Later Thursday, Premier Danny Williams said he wants regulatory authorities to examine whether it was time to upgrade the standards for the survival suits used on helicopters that carry workers to and from the province's three offshore oil platforms.

Members of the Canadian General Standards Board have questioned if the standard written in 1999 for the 2007 model suit is deficient, Natural Resources Minister Kathy Dunderdale said.

But Williams stressed that his government was not questioning the suits that were used during last week's ill-fated flight to the rigs used for the Hibernia and White Rose oilfields.

"We've no reason to believe at this particular point that any particular suit is in question as a result of any loss of life," he said.

The province has written to the Canadian General Standards Board and the Canada-Newfoundland and Labrador Offshore Petroleum Board -- which regulate the suits -- asking if the standard for them should be reviewed.

"It's very, very important on an interim basis that we know our workers are safe and as protected as they can be," he said.

"If in fact there is a standard deficiency or a standard upgrade that is needed in order to produce a better suit, then we need to make sure that our people know what they are dealing with."

Williams also said he wants a bigger search-and-rescue presence in the province.

Questions have been raised since the crash about whether the province's Cormorant helicopters based in the central town of Gander should be moved to St. John's, given the proximity of the offshore oil industry and the frequency of arriving and departing flights.

"I think it's acknowledged that there has to be a greater presence here, that it also has to be closer to the sites in question," Williams said.

"I don't think that issue is lost, quite frankly, on the federal government."

A funeral service for at least three of the victims took place Thursday. Funerals for 10 others will take place Friday and Saturday.