The wreckage of the Keystone Air Services Ltd. airplane in Thompson, Manitoba is shown in a Transportation Safety Board handout photo. The TSB says a plane that crashed in northern Manitoba last month, sending eight people to hospital, had the wrong fuel. THE CANADIAN PRESS/HO

THOMPSON, Man. - The Transportation Safety Board says a plane that crashed in northern Manitoba last month, sending eight people to hospital, had the wrong fuel.

The Navajo Chieftain aircraft operated by Keystone Air had a malfunction shortly after takeoff on Sept. 15 and tried to return to the airport in Thompson, the board said Thursday.

The plane with two pilots and six passengers aboard crashed into some trees 1.8 kilometres short of a runway.

Much of the aircraft was destroyed, but the cabin section remained largely intact. There was no fire, even though the aircraft's fuel cells were ruptured and spilled gas around the crash site.

The transportation board said the twin-engine piston aircraft was mistakenly refilled with jet-engine turbine fuel in Thompson instead of the required aviation gas.

"If you put the wrong fuel in an aircraft engine — obviously in this case the engine won't run," board spokesman Chris Krepski said. "The incorrect fuel would obviously affect the ability of the engine to operate."

The day after the crash, Keystone Air president Cliff Arlt said the company had learned that the aircraft may have been filled with jet fuel, rather than Avgas, as would have been required for the Navajo.

In a release Thursday, Keystone said the TSB's preliminary conclusion about the incorrect fuelling is consistent with the company's findings from its own investigation.

Keyson said it appears the fuel problem caused the crash.

"We note that there is no suggestion that the aircraft was not airworthy at the time of the crash, or that the crash was the result of any inflight operational issues," the release said.

Keystone said it relies on Maratech Aviation Fuels, an independent company, to fuel its aircraft in Thompson.

The safety board said its investigation continues and includes a review of aircraft fuelling procedures used by the airline and the airport.

Krepski said there are safeguards that are supposed to prevent refuelling staff from putting the wrong type of gas into a plane.

"That is part of what the investigation will look at — what the procedures are for fuelling aircraft, whether they are sufficient."

Krepski said it is too soon to say when the board will issue its final report.

This is the second crash involving a Keystone Air plane in recent years.

Four people, including the pilot, were killed and a fifth was seriously injured when a Keystone plane hit the icy surface of a lake at a remote reserve north of Dryden, Ont., in 2012.

The TSB later found that poor weather, ice on the wings and the pilot's inexperience landing in icy conditions contributed to the crash.

Keystone Air, which operates eight aircraft out of its headquarters in St. Andrews, Man., says it offers cargo, passenger and executive transportation throughout North America.

— By John Cotter in Edmonton

News from © The Canadian Press, 2015