HISTORY On June 23, 2009, about 0830 mountain standard time, an experimental Mayo RV-6A, N413RV, impacted the ground after takeoff about 1/2 mile north of the Cottonwood Airport (P52), Cottonwood, Arizona. The pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a local area flight. The pilot/owner and a certified flight instructor (CFI) were fatally injured. The airplane sustained substantial damage. Visual meteorological conditions prevailed for the instructional flight, and no flight plan had been filed. Witnesses located at the airport reported that the takeoff was normal, but on climb out the engine began to sputter. The airplane appeared to "dip" and then recovered followed by a high pitch revving sound emanating from the engine. Witnesses then saw the airplane rocking back-and-forth and then the left wing "dropped," the airplane "stalled," and entered into a nose dive before impacting the ground. PERSONNEL INFORMATION Pilot/Owner A review of Federal Aviation Administration (FAA) airman records revealed that the 64-year-old pilot/owner held a private pilot certificate with a rating for airplane single engine land. He held a third-class medical certificate issued on July 16, 2007, and it had the restriction that he must wear corrective lenses for near and distant vision. The NTSB investigator-in-charge (IIC) reviewed excerpts of the pilot's personal logbook. The pilot had an estimated total flight time of 284 hours. The last recorded flight was June 20, 2009, in the accident airplane for a total of 1.8 flight hours. He completed his flight review on August 2, 2008, at Wiseman Aviation, Flagstaff, Arizona. Certified Flight Instructor (CFI) A review of Federal Aviation Administration (FAA) airman records revealed that the 73-year-old pilot held an airline transport pilot certificate, as well as a commercial pilot certificate with ratings for airplane single engine land and glider. The pilot also held a flight instructor certificate with ratings for airplane single and multi-engine, instrument airplane, and glider. He held a second-class medical certificate dated March 17, 2008, which had the limitation that the pilot must have available glasses for near vision. No personal logbooks were made available for the CFI. The NTSB IIC obtained the aeronautical experience listed in this report from a review of the FAA medical records on file at the Airman and Medical Records Center, Oklahoma City, Oklahoma. The pilot reported on his last medical application dated March 17, 2008, an estimated total time of 31,300 hours and 30 hours in the past 6 months. MEDICAL AND PATHOLOGICAL INFORMATION Pilot/Owner The Yavapai County Office of the Medical Examiner completed an autopsy on June 24, 2009. The cause of death was listed as multiple blunt force injures due to an aircraft crash. The FAA Forensic Toxicology Research Team, Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide, cyanide, volatiles, and tested drugs. CFI The Yavapai County Office of the Medical Examiner completed an autopsy on June 24, 2009. The cause of death was listed as multiple blunt force injures due to an aircraft crash. The FAA Forensic Toxicology Research Team, Oklahoma City, performed toxicological testing of specimens of the pilot. Analysis of the specimens contained no findings for carbon monoxide, cyanide, volatiles, and tested drugs. AIRCRAFT INFORMATION The single-engine airplane was a 2000 experimental amateur built Mayo RV-6A, serial number 60117. An Aero-Sport O-360-A2A engine was installed on the airplane. The airplane was sold by the builder on January 1, 2006, and then sold to the accident pilot on May 8, 2009. According to airframe and engine logbook entries on March 11, 2009, the last inspections performed were condition inspections. The inspections had been performed and signed off by AeroMarine, Paso Robles, California. The airframe and engine total time were recorded as 471.9 hours. WRECKAGE AND IMPACT INFORMATION An FAA inspector responded to the accident site. The entire airplane was located at the accident site in an upright position. The propeller assembly had separated from the crankshaft and was partially embedded in the hard desert dirt about 10 feet from the main wreckage. Both wings remained attached at their respective locations on the fuselage, but sustained extensive impact damage. The empennage and tail section remained attached to the fuselage. TESTS AND RESEARCH The FAA inspected the engine at Air Transport, Phoenix, Arizona. The top spark plugs were removed and exhibited worn out operating signatures when compared to the Champion aviation check-a-plug chart AV-27. The propeller assembly was examined, with angular and granular separation observed at the crankshaft. One propeller blade exhibited S-bending with chord wise scratching the length of the blade. The other propeller blade was bent aft with chord wise scratching at the tip. The FAA inspector reported that the airplane had been flown two days prior to the accident, and had not been refueled. However, when he was on-scene, he was able to smell fuel in the accident area, as well as see a fuel stain on the ground. Additionally, the pilot was friends with the local RV-6 builders in the area. They helped the pilot with a pre buy inspection of the accident airplane, and reported to the FAA inspector that there were no issues noted with the pre buy inspection. At the conclusion of the engine inspection, the inspector reported finding no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.