On April 4, 2005, about 1440 eastern daylight time, a Frank D. Amador Searey experimental amateur-built airplane, N43427, registered to and operated by a private individual, as a Title 14 CFR part 91 personal flight, veered off the runway and impacted a tree while attempting to take off at Haller Airpark, Green Cove Springs, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The airline transport-rated pilot and passenger received serious injuries, and the airplane incurred substantial damage. The flight originated in Green Cove Springs, the same day, about 1415. A witness stated that he was working in his hangar and he heard the accident pilot make a radio communications transmission announcing his intent to take off. The witness further stated that he also heard power being increased on the accident airplane's engine, followed shortly thereafter by power being reduced. He said he turned to observe what was happening, and saw the airplane swerve to the left during the takeoff roll. It crossed the centerline and left side of the runway, transited the ditch, and impacted a tree before coming to rest. The witness said he immediately asked his wife to call 911, and he ran to the airplane to render assistance. The pilot stated that after having been in the traffic pattern, he landed, he was preparing to take off again. He said he turned the airplane 180 degrees on the runway to back taxi for takeoff, and during the turns, the flight controls seemed normal. As he slowly added power to take off, and as the speed increased, he said it required more right rudder control input to bring the airplane back to the centerline of the runway. At about 45 mph he said he aborted the takeoff, far to the left of the centerline, and the airplane departed the runway, hit a drainage grating, transited a ditch, ascended a slight grade, and impacted a tree. According to an FAA inspector who responded to the accident, the airplane's rudder had jammed full to the left, and the pilot's left rudder control cable was found to have jammed between the upper seat rail structure tube, and the lower rudder foot rest rail structure tube. After the cable was released, full rudder travel was restored in both directions. The inspector further stated that when he examined how the rudder cables had been routed, it appeared to him that the rudder cable on the right side of the airplane had been routed with greater separation between it and the rails, when compared with the left cable, which had jammed.