On November 25, 2006, approximately 1300 mountain standard time, a Cessna 180K, N180BM, departed the right side of the runway and impacted a ditch during the takeoff roll at Skypark Airport, Bountiful, Utah. The private pilot and his passenger were not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which was departing for Ogden, Utah, was being operated in visual meteorological conditions. There was no report of an ELT activation. During the initial on-site interview with an FAA Inspector, the pilot stated that about 250 feet into the takeoff roll, while the aircraft was near the centerline of the runway, the right brake locked up, causing the aircraft to veer to the right. During that interview, the pilot said that he was unable to overcome the veer to the right with application of left rudder and left brake. During a follow-up phone interview with the NTSB IIC and the same FAA Inspector, the pilot, who failed to execute an NTSB Form 6120.1/2, gave a different account of the sequence of events. During this second interview he said that about 100 feet into the takeoff roll, with the aircraft near the centerline, something caused the aircraft to start pulling to the left. He said that the aircraft came close to the left edge of the runway, and he initially reduced power, but as he corrected back to the right, he decided to continue the takeoff. Reportedly, as he continued the takeoff, the aircraft pulled hard to the right, and he was unable to keep it from departing the right side of the runway. According to tire tracks and skid marks left on the runway, by the time the aircraft was about 200 feet into the takeoff roll, its left wheel was about three feet from the left edge of the 75-foot wide runway. The tire tracks show that as the aircraft neared the left side of the runway, the right tire skidded for about 20 feet. During the last half of the skid, the skid mark curved back to the right. Then for about 30 feet, there was no skidding of either tire. This was followed by another 20-foot skid of the right tire, during which the ground track increased even further to the right. Neither tire skidded for about another 50 feet, but then both tires skidded for another 20 feet, with these skid marks crossing the centerline of the runway at about a 45 degree angle. About another 50 feet down the runway, about 10 feet from where the ground track departed the right side of the runway, both tires skidded again, this time with a considerable amount of sideways scuffing. After departing the right side of the runway, the aircraft slid sideways until impacting a drainage ditch that runs parallel with the runway centerline. After impacting the ditch, the aircraft came to a stop in an upright position, heading to the southeast.