VANCOUVER, April 14 -- The crash of a cargo plane in Vancouver's North Shore mountains on Monday was due to an uncontrolled descent, the Transportation Safety Board of Canada (TSB) said Tuesday.

Search crews found the main fuselage of Carson Air Flight 66 with the bodies of two pilots still inside in the steep and heavily wooded terrain southeast of Crown Mountain Monday afternoon, said TSB investigator Bill Yearwood at a press conference.

Yearwood said all indications showed that the two pilots suddenly lost control of the aircraft, dropping from 2,400 meters to about 900 meters - the height at which the wreckage was found - in less than a minute.

"The radar track showed a very steep descent, and the crew did not call, declare an emergency or have any stress which gives us an idea that whatever happened, happened suddenly. The radar track gives us information on how fast it was descending ... and that is consistent with uncontrolled flight," he added.

Yearwood said the plane was not equipped with cockpit voice or flight data recording systems. As a result, the specific cause of the crash would have to be pieced together from the physical evidence, which he said would take time.

The crashed plane took off from Vancouver International Airport Monday morning heading for Prince George Airport. But air traffic control lost radar contact with the flight after about 25 minutes, when the plane was crossing the North Shore Mountains.