Investigators have ruled out engine failure or problems with fuel in a plane crash last week in northern Saskatchewan that seriously injured seven of the 25 people on board.

The 22 passengers and three crew aboard the two-engine ATR 42 turbo prop survived the incident at Fond du Lac, a mainly Dene community on Lake Athabasca. However, six passengers and one crew member were seriously injured. The 18 other occupants of the aircraft suffered some injuries.

On Wednesday, Eric Vermette of the Transportation Safety Board (TSB) said investigators have drawn two key conclusions at this early stage of the investigation.

Story continues below advertisement

Both of the plane's engines were working when the aircraft operated by West Wind Aviation began striking trees, and then went down after take off on Dec. 13 just after 6 p.m.

"There was no engine failure of either engine prior to the aircraft coming down and settling into the trees and into the terrain," Mr. Vermette said in Winnipeg.

He also said fuel was not an issue. "There was ample fuel on board the aircraft," he said, adding that analysis of fuel samples is under way.

Mr. Vermette said it was "quite remarkable" that there was no fire in the crash although he added he has no idea why that was the case.

He said there is no timeline on completing the investigation. "We take the time required to ensure that we do a thorough investigation," he said, although he said the TSB will release any pertinent findings as they come up. "At this point, it's too early to speculate on the cause of the accident."

The plane was supposed to fly 80 kilometres from Fond du Lac to Stony Rapids, and then on to Wollaston and Prince Albert.

Mr. Vermette took note of the outpouring of help on the scene after the plane went down as RCMP officers and residents of the 900-person community rushed to the scene to help.

Story continues below advertisement

"I think it's remarkable that people were able to come together and help the passengers and crew members on this aircraft," he said.

Mr. Vermette said investigators planned to look into whether there are lessons from the fact that no one died in the crash.

West Wind has suspended the operation of its ATR flights while it conducts a review of its operations. Founded in 1983, the company operates from Saskatoon, La Ronge and Stony Rapids as well as from satellite locations in northern Saskatchewan.

The company's website says it is First Nations- and employee-owned. The majority owner, Athabasca Basin Development, represents seven area communities. Prince Albert Development Corp. and employees hold minority stakes.

The website describes the ATR 42 as a "sophisticated" aircraft designed for short-haul flights. The airline says it has grounded its other ATR 42 planes,

Mr. Vermette said the TSB investigation team has been on site since Dec. 14. They have surveyed and photographed the site, removed all luggage, personal effects and cargo to determine the weight of the aircraft and checked the cockpit for documents and electronic instruments.

Story continues below advertisement

They have also removed the flight-data recorder, emergency locator transmitter and the cockpit voice recorder, which have been sent to a TSB lab for assessment.

They have also interviewed first responders, passengers, eyewitnesses, airport employees and other witnesses. "Everybody has been co-operative so far," Mr. Vermette said.

He declined to offer details when asked about data secured from the flight data recorder as well as the experience level of the pilots. He said investigators will be looking at maintenance records of the aircraft.

There is no official weather reporting source at Fond du Lac so investigators are looking for data from other weather reporting sources in the "surrounding area" to get a sense of what was happening at Fond du Lac, Mr. Vermette said.

"The examination and analysis phase is just starting and there is much work to be done," he said.