On February 2, 1996, about 1715 eastern standard time, a Yakoblev 52 experimental airplane, N77YK, registered to a private owner, operating as a 14 CFR Part 91 personal flight, crashed while maneuvering in the vicinity of Boynton Beach, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was destroyed. The private pilot was fatally injured. The flight originated from Willis Gliderport, Boynton Beach, Florida, about 30 minutes before the accident. A witness stated neighbors observed the airplane make a low pass down runway 27 at about 900 to 1,000 feet. The airplane made three barrel rolls and lost altitude on all three rolls. The airplane remained in closed traffic and made a second pass down the runway at about 120 mph, and at about 100 to 200 feet. The airplane was observed to initiate a pull up and did a barrel roll to the left. When the airplane was 90 degrees off heading, it was observed to enter a vertical nose down descent and collide with the ground. On scene examination of the crash site conducted by the FAA revealed the airplane collided with the ground in a near vertical nose down attitude. The engine and composite propeller blades were buried below the ground. Both the left and right wing were displaced aft and sustained compression along the leading edge of both wings. The left and right fuel cells were ruptured. The fire department stated fuel was present at the crash site. Examination of the airframe, flight controls, engine assembly and accessories revealed no evidence of a precrash failure or malfunction. All components necessary for flight were present at the crash site. Continuity of the flight control system was confirmed for pitch, roll, and yaw. The next of kin could not locate the airplane log books. Post-mortem examination of the pilot was conducted by Dr. James A. Benz, Palm Beach County Medical Examiner's Office, Palm Beach, Florida, on February 2, 1996. The cause of death was multiple blunt traumatic injuries. Post-mortem toxicology studies of specimens from the pilot was performed by the Palm Beach County Sheriff's Laboratory. These studies were positive for alcohol, 0.10 percent (blood) weight /volume, and 0.92 percent (gastric fluid) weight /volume. A comprehensive drug screen by fluorescence polarization immunoassay and gas liquid chromatography revealed no drugs were detected.