On January 20, 2000, at 0932 Eastern Standard Time, a Cessna T310R, N137TR, was substantially damaged when it collided with a fence during an aborted takeoff from the Robertson Field Airport (4B8), Plainville, Connecticut. The certificated commercial pilot and pilot rated passenger were not injured. Instrument meteorological conditions prevailed and an IFR flight plan was filed for the business flight conducted under 14 CFR Part 91, destined for Portland, Maine (PWM). In a telephone interview, the pilot said the purpose of the flight was to travel to PWM to conduct business. He said he and his passenger arrived at 4B8 approximately 0800, and that snow was falling during the drive to the airport. The pilot said the airplane's engines and interior were pre-heated before his arrival. He said the pre-flight, engine start, and taxi checks were all performed by the checklist. The pilot taxied the airplane into position for take off from Runway 02 after he received his IFR clearance. The pilot was flying the airplane from the right seat. He said flaps were set at 10 degrees and full engine power was applied before the brakes were released for the take off roll. During the takeoff roll, the pilot noticed the cockpit door was open. He said: "I heard a 'clunk' and then I saw the door handle had popped half open. I noticed I could see a crack of daylight and heard a rushing sound of wind. We weren't half way down the runway, so I decided to abort. Initially, the braking was so good I didn't have any concerns about stopping. We got to the end but suddenly we weren't braking and we weren't turning. I tried to turn off at the taxiway but it wouldn't turn. It just went straight ahead. It didn't move a dot off centerline. We went off the edge and down the cliff." In a written statement, the pilot said, "As the aircraft proceeded down the runway I tried to reclose the door latch, but against the door seal it would not relatch." The airplane overran the departure end of the runway, continued down a steep embankment, struck a fence and crossed a road. In a written statement, the pilot rated passenger said: "[The pilot] heard a noise come from the door and saw visible light around the door seal. He immediately elected to abort the take-off before mid-field. The power was brought to idle and braking was commenced. There was plenty of runway left to stop the plane and initially braking was effective. Everything appeared normal and it seemed that the plane would stop in time. However, the brakes became ineffective towards the end of the runway and while the plane was not going very fast it went over the edge." In a telephone interview, a flight instructor reported he was with a student and his airplane when they noticed N137TR on the runway. He said: "We were parked facing the runway about 2/3 down and about 3 to 4 hundred feet off the runway. There was light snow, about 1/4 inch on all surfaces. I looked up and saw a 310 pass by about 30 or 40 knots. I said to my student, 'Geez, I hope he's taking off. I guess not. On no, I know what's gonna happen here so let's watch'." The flight instructor said he and his student secured the airplane and drove to the accident site. He said: "From the time we saw the airplane go by to the time we got there was maybe 3 to 5 minutes. There were tracks in the snow as far [down the runway] as I could see. If I had to estimate the braking, I would estimate it as fair. Fair to poor." The pilot reported 1,548 hours of flight experience, 836 hours of which were in make and model. The pilot rated passenger reported 600 hours of flight experience, 165 hours of which were in multi-engine airplanes. He reported approximately 90 hours in the Cessna 310. When questioned about the performance and handling of the airplane, the pilot responded: "Everything was working fine. The engines came right up and were working well. Everything was fine with the aircraft." The pilot provided weight and balance information for the accident flight. According to the pilot, the airplane was 4,948 pounds at takeoff. The weather reported at the Hartford-Brainard Airport, 10 miles east of 4B8, was visibility 2 1/2 miles in snow. The winds were variable at 3 knots, the temperature was 16 degrees, and the dewpoint was 7 degrees. The runway at the Robertson Field Airport was 3,612 feet long. According to the Accelerate Stop Distance chart in the Cessna Model 310 Owner's Manual, the approximate accelerate stop distance for the airplane at its given weight was 2,680 feet. Among the conditions outlined for the chart were wing flaps in the 'up' position and a level, hard surface, dry runway.