The Propair Inc. Beechcraft 200 Super King Air, with two pilots and ten passengers on board, was preparing to make a charter flight under instrument flight rules from Sept-?les Airport, QC (YZV) to Montreal-Dorval International Airport, QC (YUL). At 17:00, the co-pilot, in the left seat, began the takeoff roll on runway 09. At an indicated airspeed of about 90 knots, 5 knots below rotation speed (VR), the aircraft began to drift to the left, toward the runway edge. The copilot attempted unsuccessfully to correct the takeoff track using the rudder. At around 100 knots, just before the aircraft exited the runway, the co-pilot pulled the elevator control all the way back and initiated a climb. At about the same moment, the pilot-in-command throttled back, believing that a collision with the snowbank at the runway edge was inevitable. The aircraft descended until it struck the snow-covered surface to the north of the runway and slid on its belly before coming to rest on a heading opposite to the takeoff heading. The pilot-in-command was slightly injured. The aircraft sustained considerable damage. The occupants used the main door to evacuate the aircraft. CAUSES AND CONTRIBUTING FACTORS: The aircraft crashed as a result of the lack of cockpit co-ordination when the pilot-in-command took control of the aircraft as the aircraft was airborne. The following factors contributed to the occurrence: marginal environmental conditions; contaminated runway surface; poor cockpit management; ineffective briefing; and, inadequate training for rejected take-offs.