On August 18, 2007, about 1035 eastern daylight time, a Beech B36TC, N6750C, registered to, and operated by a private individual, as a Title 14 CFR Part 91 personal flight, crashed while attempting to take off in Clearwater, Florida. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the flight to Spruce Creek, Florida. The private-rated pilot received serious injuries, and two passengers received minor injuries. The flight was originating at the time of the accident. The pilot stated that the day was hot and humid, and during the takeoff-roll he rotated at 85 knots indicated airspeed, with the engine developing full power, and no problems being noted. About 60 feet off the ground he said he raised the landing gear and shortly thereafter the airplane did one yaw to the right, and one yaw to the left. It then settled/pancaked straight down. He said it did not feel like a stall had occurred, and he did not understand why it yawed and descended. He said he supposed it could have been a stall, but he had been familiar with stalls in the airplane, and it was not a normal stall. Instead it felt like he lost elevator and rudder control, or as if the autopilot had taken over the airplane. At the time, he said the airplane was in a climb attitude, at an indicated airspeed of 85 knots, and as it descended he said he saw the top of trees, and then "jerked" the landing gear up. He said the airplane landed hard and flat and then skidded some distance. According to the pilot the engine was producing good power, and was loaded within the weight and balance envelope at the time, having 105 gallons of fuel on board, along with himself and two normal sized adults. The owner of the accident airplane said that he both observed the takeoff, and later spoke with the pilot while he was in the hospital, and the pilot told him that the takeoff roll had been uneventful, however, after rotating, and when about 50 feet in the air, the flight controls became mushy, and he did not have any elevator or rudder control. An FAA inspector responded to the scene of the accident, and interviewed witnesses. According to the inspector, witnesses all stated that they saw the airplane lift off in the vicinity of the fuel farm, which is about 1100 feet from the beginning of the runway, and as the airplane climbed, they noticed that its wings began to rock increasingly, and the airplane began to porpoise. They further stated that the gear had been retracted when they saw the airplane at that point, and from what they saw it appeared as if the airplane simply ceased flying, and descended impacting the ground. According to the witnesses, the engine sounded as if it was operating normally, and the propeller had also been rotating throughout the takeoff. The FAA inspector who responded to the scene said that during the course of his investigation the flight controls were noted to be functioning normally, and that there were no anomalies noted. The inspector further stated that he took a vehicle and measured the distance from the beginning of the runway, to the location where the airplane first impacted. He said the distance was 1100 feet, and there were several evenly positioned propeller slash marks in the asphalt on the runway, and the slash marks began at the first point of impact, and proceeded in the direction of travel. He also stated that he found 45 gallons of fuel remaining in the airplane, and that persons aboard the airplane included the pilot and two adults. In addition, he said it had been hot and humid day. An FAA inspector, as well as a technicians from Teledyne Continental Motors, conducted a detailed examination of the airplane's engine and accessories and no anomalies were noted.