On April 30, 1997, at 1835 eastern daylight time, an experimental airplane, a Porter STOLP SA-750, N513EP, was destroyed when it collided with terrain while maneuvering near East Huntingdon Township, Pennsylvania. The certificated private pilot was fatally injured. Visual meteorological conditions prevailed for the personal flight that originated at the Mount Pleasant/Scottsdale Airport (P45), Mount Pleasant, Pennsylvania, about 1800. No flight plan was filed for the flight conducted under 14 CFR Part 91. According to the Mt. Pleasant Airport manager, the pilot had performed a pre-flight inspection to include the removal of a cowling to "...clean out a bird's nest." He said the pilot purchased 9.2 gallons of fuel after returning from a flight on April 26, 1997, and the airplane had not been flown since that date. He said the pilot habitually filled the fuel tanks after each flight "...to prevent condensation in the tanks." The manager said that when the airplane "...started up and taxied out everything sounded normal. The airplane sounded great." Several witnesses provided statements to the Pennsylvania State Police. According to the police report one witness stated, "...was unsure of the time but heard and saw the plane flying at one point. He heard the engine again and saw the plane doing a stunt. He saw the plane do another stunt. He then saw the plane go tail over end. The motor was more quiet than before and then shut off. The plane went straight down and he heard the impact." Another witness "...heard something crash in the woods. She then heard the plane's engine sputter and heard another crash." A third witness reported in a telephone interview that "...the plane was doing a stunt. The plane was going end over end. He was definitely lower when doing the stunt than the other planes. It started end over end then it started spinning the other way. Then it was just out of control. I thought he was going to come down on my house. The engine was definitely running before it went out of control. It didn't shut off until it was out of control." In a written statement, the same witness stated, "The plane sounded normal to me. I watched him do a loop first, then the plane started to flip wing over wing. After that, the engine shut off and the plane continued spinning and flipping uncontrollably until I lost sight of it..." In a written statement, an FAA Inspector stated examination of the wreckage revealed, "All flight control surfaces were attached and intact. Flight controls had continuity as near as could be determined due to the severe destruction of the front fuselage area." Examination of the airplane's engine was conducted on April 30, 1997, under FAA supervision. The engine rotated freely through the vacuum pump drive after removal of the right magneto, which was impact damaged. Thumb compression and suction was confirmed in all cylinders. The propeller blades displayed bending and chordwise scratching. ADDITIONAL INFORMATION A Federal Aviation Administration Inspector conducted a telephone interview with the pilot's aerobatics instructor. According to the Inspector's Record of Conversation: "[The instructor] was to meet [the pilot] at the airport on the day of the accident and observe his performance. [The pilot] took off before [the instructor] arrived and never returned. [The instructor] stated that the acroduster had a large fuel capacity but the top auxiliary tank and the main tank were never completely filled. The added weight would hinder the aircraft's performance. ...He considered [the pilot] a safe and cautious pilot who never cut corners. [The pilot] was involved in acrobatic competition and needed to practice three additional maneuvers to move up to the next class. These were the Cuban-eight, Emmilman, and Hammerhead stalls. [The instructor] stated that the easiest maneuver to get into trouble is the Hammerhead stall. If it's not done right, a pilot could get into an inverted spin. After I described the way the aircraft was flying from the witness reports, [the instructor] stated that [the pilot] may have been practicing a routine by doing the Emmilman and then a 1-turn spin. At the end of the spin, if the nose is pushed forward too quick, hard, or soon, the aircraft will go into an inverted spin." A review of the pilot's logbook revealed the pilot's flight experience totaled 334 hours; 51 in the SA-750. He had flown 6/10 of an hour April 21, 1997. Prior to that date, the pilot had not flown in 6 months.