HISTORY OF FLIGHT On July 21, 2001, at 1245 central daylight time, an experimental Smith Kelly-D biplane, N303SM, was destroyed when it experienced an in-flight separation of the right upper wing and impacted terrain about 1/4 mile north of the Poplar Grove Airport (C77), Poplar Grove, Illinois. The private pilot and passenger received fatal injuries. The 14 CFR Part 91 pleasure flight had departed C77 at 1230 on a local flight. The airplane was observed doing aerobatic type maneuvers prior to the in-flight break-up. Visual meteorological conditions prevailed and no flight plan was filed. The pilot had flown N303SM to C77 as part of the 3rd Annual Midwest Regional American Hatz Association fly-in that was being held at C77 over the weekend of July 20 and 21st. Witnesses reported the pilot had given passenger rides in the biplane during the morning. A witness reported that airplane landed and refueled. After refueling, a passenger was loaded and the airplane departed on a local flight. A witness reported he observed the airplane coming from the north of the airport and flying toward the airport. He reported that he, "saw the Kelly-D airplane coming out of a maneuver of some kind. He continued west at approx. 800-1000'. He pulled up, rolled to the left (inverted) and pulled out (1/2 loop). He repeated the same maneuver going east, and as he leveled out I saw what looked like a large piece of fabric and another object leave the airplane. The fabric fell slowly the other object a little faster. The airplane continued for a couple seconds and then rolled over and spiraled into the ground." The witness reported the maneuver was smooth and that it could not have pulled more that 3.5g's during the maneuver. He reported the failure occurred as the airplane was leveling off. He reported the engine was operating during the entire flight and there was no indication of an engine problem. Witnesses reported the airplane nosed over and spiraled into the ground. The airplane impacted into a cornfield located just to the north of the airport. PERSONNEL INFORMATION The pilot was a commercial pilot with a single engine land rating. The pilot did not have an instrument rating. He held a Second Class Medical Certificate that was issued on May 15, 2001. The pilot reported his total flight time was 2,100 hours during his last medical exam. The pilot also held an Airframe and Powerplant (A&P) Mechanic certificate. AIRCRAFT INFORMATION The airplane was a single engine amateur-built experimental Smith Kelly-D biplane, serial number 38. The airplane seated two and had a maximum gross weight of 1,600 pounds. The engine was a 150 horsepower Lycoming L-320-E2D engine. The airplane was for sale. According to an advertisement posted on the Internet on June 21, 2001, the airplane had recently received an annual condition maintenance inspection. At the time of annual condition inspection, the airplane had a total flight time of 60 hours since new. The engine had a total time of 1,090 hours since overhaul and 60 hours since a top overhaul. A witness reported the airplane's fuselage and wings were originally built by a builder located in New York state. According to the airplane builder's log, the original builder started on the project in December 1984. The builder's log indicated the pilot purchased the "project" airplane in September 1997 and completed building the airplane in May 2000. The airplane received a Special Airworthiness Certificate on May 12, 2000. METEOROLOGICAL INFORMATION At 1254, the observed weather at Rockford (RFD), Illinois, was: winds 000 at 5 knots, visibility 10 miles, clouds broken 3,100 feet, temperature 32 degrees C, dew point 22 degrees C, altimeter 29.91. WRECKAGE AND IMPACT INFORMATION The main wreckage was located in a cornfield just north of the airport at coordinates N 42 degrees 19.73 minutes, and W 088 degrees 55.35 minutes. The nose of the aircraft was found heading 150 degrees. The engine, cockpit, fuselage, right lower wing, and empennage were found together at the initial point of impact. Emergency response personnel moved the upper and lower left wing about 20 feet to aid in the recovery. The right upper wing impacted the ground in a bean field about 1/4 mile from the main wreckage. The airplane impacted the terrain in a steep nose down attitude. One of the wooden propeller blades was bent opposite the direction of rotation, broken at the hub, and was in splinters. The other blade was broken about mid-span. A propeller slash was found in the dirt at the point of propeller impact. The cockpit and fuselage were destroyed. The empennage remained intact. The right horizontal stabilizer had leading edge damage. Flight control cable continuity was confirmed from the rudder and elevators to the cockpit controls. The left upper and lower wings exhibited leading edge crush damage and buckling. The right lower wing remained attached to the fuselage by its aft mount. Its leading edge did not exhibit crush damage. The aileron cable continuity from the cockpit controls to the upper and lower ailerons was not confirmed. The flying and landing wires and the clevis ends were examined. Six of the jam nuts were found loose. Failed sections of the right wing front and rear upper spars with doublers, and a section of the left wing upper spar, were sent to the United States Department of Agriculture (USDA) Forest Products Laboratory, Madison, Wisconsin, for examination. The right wing upper strut and upper attachment lug were sent to the National Transportation Safety Board's (NTSB) Materials Laboratory for examination. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot on July 23, 2001, in Belvidere, Illinois. A Forensic Toxicological Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute. The report concerning the pilot was negative. TESTS AND RESEARCH The USDA Forest Products Laboratory examined the left and right wing spar sections and their respective doublers. The examination of the wood spar composition revealed the cellular structure of the spars was consistent with that of Sitka Spruce, and the species that made up the plys of the plywood doublers were maple and yellow poplar. Chemical analysis of the adhesive bonds indicated Urea-formaldehyde was used for attaching the doubler plates. The examination of the left front upper spar revealed that the adhesive used on the plywood doubler did not cover the entire area being bonded to the spar. The Forest Products Laboratory report stated, "There was also very little penetration of the adhesive into the spar." The examination of the right front and rear upper spars revealed the compression and tension surfaces. The examination of the bond on the right upper rear spar doubler revealed the doubler was still bonded to the spar, but there was a lack of adhesive at the outer edges of the doubler plate. The lack of adhesive created a gap between the spar and the doubler. The NTSB Materials Laboratory examination of the fractures of the right wing upper strut and upper attachment lug were typical of overstress separations. There were no indications of preexisting fatigue or significant corrosion on any of the components. ADDITIONAL INFORMATION The FAA was a party to the investigation. The airplane wreckage was released to Mr. Britt Smith.