On April 6, 2006, about 0845 eastern daylight time, an Aero Commander 100, N3602X, registered to and operated by a private individual, as a Title 14 CFR Part 91 personal flight, aborted the takeoff at Buchan Airport, Englewood, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The private-rated pilot and passenger were not injured, and the airplane incurred substantial damage. The flight was originating at the time of the accident. The pilot stated that prior to takeoff, the engine run-up was normal. He further stated that the initial takeoff roll on runway 30 was normal as well, however, about 2/3 of the length of the runway, the airspeed indicated 60 mph, so he aborted the takeoff. He said he retarded the throttle control, and applied the brakes, but the 2,040-ft runway consists of sod and sand, and it was rough and wet, so the braking action did not "work well." He said the airplane impacted the top of a 5 ft-high berm, and descended into a 8 to 10 ft-deep ditch, incurring substantial damage On June 2, 2006, a post accident examination of the airplane and its engine was performed by an FAA inspector, as well as an FAA licensed airframe and powerplant mechanic. During the examination the engine was given a "test-run", and no preaccident anomalies were noted to exist.