DURING THE TAKEOFF ROLL ON A CONTAMINATED RUNWAY, THE COPILOT NOTED A LACK OF ACCELERATION. JUST BEYOND MIDFIELD, THE COPILOT CALLED FOR AN ABORT, HOWEVER, THE PILOT ELECTED TO CONTINUE. THE AIRPLANE DID NOT REACH VR AND THE PILOT ATTEMPTED TO ROTATE THE AIRPLANE AT THE END OF THE RUNWAY. THE AIRPLANE COLLIDED WITH AND TRAVELLED THROUGH A FIVE FOOT HIGH SNOWBANK AND CAME TO REST IN A FIELD APPROXIMATELY 500 FEET FROM THE END OF THE RUNWAY. DURING THE POSTCRASH INVESTIGATION, EVIDENCE INDICATED THAT THE PARKING BRAKE HAD BEEN IN THE INTERMEDIATE POSITION OR 23 PERCENT OF MAXIMUM BRAKING. THE PARKING BRAKE WARNING LIGHT WAS FOUND TO OPERATE CORRECTLY IF THE PANEL LIGHTS WERE SET IN THE BRIGHT LIGHT POSITION. IN THE DIM POSITION, THE WARNING LIGHT WAS INOPERATIVE. DURING THE ON SITE INVESTIGATION, THE PANEL LIGHTS WERE FOUND IN THE DIM POSITION.