On May 13, 2011, at 1632 eastern daylight time, an experimental light sport, Carothers Zenith CH 701 airplane, N433UB, registered to a private owner, collided with a tree while landing at a private strip in the vicinity of Tidioute, Pennsylvania. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91. No flight plan was filed and visual meteorological conditions prevailed. The private pilot and a passenger sustained serious injuries. The flight originated from the pilot's private strip at 1615. The pilot stated he had been operating the airplane at a low altitude with a passenger. He turned on to final leg to land at his private strip and hit a tree with his right wing. The airplane rolled right, he added power, the nose of the airplane pitched down, he pulled back on the control stick, and the engine continued to run until the airplane collided with the ground in a nose down attitude and nosed over inverted. The pilot stated he did not experience any mechanical problems with the airplane, and that "the accident was caused by pilot error." Witnesses, who live near the pilot's house, stated they had observed the airplane prior to the accident, flying low above the trees. One witness stated the pilot had circled their property and had allowed the wheels of the airplane to touch the top of the trees before he flew along a river and returned. They observed the airplane start a descent, flying east towards the pilot's house, and crossing a highway. The left wing of the airplane struck a tree and the airplane rolled to the left. The nose of the airplane pitched down, the engine continued to run, the airplane collided with the ground, and nosed over inverted. The pilot, age 48, held a private pilot certificate issued on August 2, 2008, with a rating for airplane single-engine land. The pilot did not hold a Federal Aviation Administration (FAA) repairman certificate. The pilot's logbook was not located at the crash site. The pilot stated in an interview he had logged 150 total flight hours; of which, 2 hours were in the Zenith CH 701. The pilot had logged 63 hours of pilot-in-command. The pilot had flown 1 hour in the last 90 days and 1 hour in the last 30 days, all in the Zenith CH 701. The pilot was issued a third-class medical certificate on July 2, 2007, with no limitations. The pilot stated he was not under the influence of drugs or alcohol at the time of the accident. Post accident hospital laboratory specimens from the pilot were obtained through a subpoena and forwarded to the FAA Bioaeronautical Research Science Laboratory (CAMI),Oklahoma City, Oklahoma, for toxicology screening. The specimens were not tested for carbon monoxide and cyanide. No drugs were detected in the blood. Ethanol, 133 (mg/dl, mg/hg) was detected in the serum and 128 (mg/dl, mg/hg) ethanol was detected in the blood. Testing conducted at the hospital at 1800 hours on the day of the accident indicated that the pilot's blood alcohol level was 149 mg/dl(0.149 percent). The Zenith CH 701 is a two-place airplane with a tricycle landing gear, serial number 6695, built by the registered owner in 2011. A Volkswagen 2276, 100-horsepower engine powered the airplane. The registered owner stated the airplane did not have any logbooks, a current condition inspection, airworthiness certificate, or approved FAA operating limitations. According to the registered owner the engine had 100 total hours and the airframe had 2 hours at the time of the accident. The HOBBS meter at the accident site showed 2.1 hours. Examination of the crash site revealed the nose section was bent upward 90- degrees. The engine cowling was damaged and remained in place. The propeller assembly remained attached to the propeller crankshaft flange. The wooden propeller blades separated from the propeller hub. One propeller blade was located under the left side of the wreckage. The remaining propeller blade was fragmented and located about 20 feet to the right of the airplane. The engine assembly remained attached to the engine mounts and was displaced to the left. The nose landing gear remained attached to the airframe and was bent aft. The windscreen was destroyed. The cabin area was compressed aft to about 5 feet aft of the cabin seats. The cabin seats remained intact and both seatbelts and shoulder harnesses were in use at the time of the accident. The instrument panel was distorted. The throttle was in the closed position. Continuity of the flight controls was confirmed to all flight control surfaces. The left and right main landing gear remained attached to the airframe. The right wing remained attached to the tubular steel cabin area and was bent upward and pushed aft. The fixed leading edge slats were damaged. The full length flaperon assembly was not damaged. The wing struts remained attached to the wing and the fuselage. The swept up rear fuselage, inverted stabilizer, and left and right elevator were not damaged. The all-flying rudder was damaged. The left wing remained attached to the tubular steel cabin area and was bent upward and pushed aft. The fixed leading edge slats were damaged. The full length flaperon assembly was not damaged. The wing struts remained attached to the wing and the fuselage. A visual examination of the engine assembly and associated components revealed no anomalies.