HISTORY OF FLIGHT On August 31, 2001, at 1645 central daylight time, an amateur built, experimental Spears RV-6, N910RS, was destroyed by impact forces and subsequent ground fire about 1 mile west of Campbell Airport (C81), Grayslake, Illinois. The airplane departed controlled flight prior to ground impact. The private pilot received fatal injuries. The 14 CFR Part 91 personal flight had originated from Roanoke, Texas, with C81 as the intended final destination. It is unknown where the airplane had last landed for refueling prior to proceeding to C81. Visual meteorological conditions prevailed. No flight plan was filed. A witness reported the airplane was flying at about 500 feet above ground level (agl) and was circling towards the airport when the airplane "barreled" left, recover, and then the nose of the airplane went straight down. Another witness reported seeing the airplane circling before the airplane nose dived into the terrain. PERSONNEL INFORMATION The pilot was a private pilot with a single engine land rating. He held a Third Class Medical certificate that was issued on August 29, 2001. The pilot reported his total flight time was 1,250 hours during his last medical examination. AIRCRAFT INFORMATION The airplane was a single engine, amateur built, experimental Spears RV-6, serial number 1. It seated two and had a maximum gross weight of 1,600 pounds. The engine was a 180 horsepower Lycoming O-360-A1F6D engine. The airplane's logbooks were not recovered during the course of the investigation, and the airplane's flight hours and maintenance history is unknown. METEOROLOGICAL INFORMATION At 1656, the observed weather at O'Hare Airport (ORD), Chicago, Illinois, located 24 nm to the southeast of the accident site was: wind 040 degrees at 14 kts gusting to 22 kts, visibility 10, clouds scattered 2,200 feet, clouds broken 3,000 feet, temperature 21 degrees C, dew point 16 degrees C, altimeter 29.96. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was located about 1 sm west of C81 in a bean field. The airplane impacted the ground on a heading of about 185 degrees. The wreckage path was limited to the initial point of impact. The engine cowling, cockpit, and the wing areas that contained the fuel tanks were consumed by fire. The left and right wings remained attached to the fuselage. The empennage was found about 10 feet forward of the engine and cockpit. The tailcone was consumed by fire. The ground fire covered an area about 70 feet in front of the airplane. The leading edges of the left and right wings were crushed and buckled aft along their outboard wing spans. Both the left and right wing flaps and ailerons remained attached to the wings. The flight controls from the cockpit to the elevators and rudder exhibited continuity. The aileron control tubes were attached at the control surface attach points. The aileron control tubes were found broken near the wing attach points and were consumed by fire in the cockpit area. The flap mechanism had continuity. The flap rod ends were removed for further metallurgical examinations. The visual inspection of the engine revealed that the engine sustained substantial impact damage to the front and bottom areas of the case. All the exhaust stacks and intake tubes were damaged. Most of the pushrod tubes incurred damage. The rear mounted accessories were fire damaged. The dual magneto was mostly consumed in the fire. The carburetor was separated from its mount flange and remained attached only by the mixture cable. The intake air duct and box were smashed into the intake side of the carburetor. The engine could not be rotated in either direction. The crankshaft was separated in the nose seal area with a fracture surface that had signatures consistent with torsional overload. The propeller blades exhibited "S" bending. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot at the Lake County Coroner's Office on September 1, 2001. A Forensic Toxicology Fatal Accident Report was prepared by the Federal Aviation Administration's Civil Aeromedical Institute. The reported indicated the following results: No carbon monoxide detected in blood. No cyanide detected in blood. No ethanol detected in vitreous. 0.019 (ug/ml, ug/g) Tetrahydrocannabinol (Marihuana) detected in blood. 0.043 (ug/ml, ug/g) Tetrahydrocannabinol Carboxylic Acid (Marihuana) detected in blood. 0.052 (ug/ml, ug/g) Tetrahydrocannabinol (Marihuana) detected in bile. Tetrahydrocannabinol Carboxylic Acid (Marihuana) detected in bile. TESTS AND RESEARCH The left and right flap rod ends were examined by the National Transportation Safety Board's Materials Laboratory. The NTSB metallurgist's examination revealed that the left and right flap attachment rod ends had tensile shear fracture features consistent with combined tension and bending overstress. There were no indications of a preexisting condition such as fatigue or corrosion. ADDITIONAL INFORMATION Parties to the investigation included the FAA and Textron Lycoming. The airplane wreckage was released to Ms. Harriet Bruerer.