On December 26, 2003, about 0900 Pacific standard time, the propeller of a Cessna 172L, N7668G, contacted the pilot while he was hand propping the airplane at the Nut Tree Airport, Vacaville, California. The pilot, also the registered owner, was operating the flight under the provisions of 14 CFR Part 91. The private pilot sustained fatal injuries; the airplane was not damaged. The flight was destined for the Lincoln Airport, Lincoln, California, and was originating at the time. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot succumbed to his injuries on January 2, 2004. The responding Solano County Sheriff's Office deputy reported that family members discovered the injured pilot on December 27. The pilot sustained head injuries, and was seated in the passenger seat of his vehicle that was parked at the airport. The airplane was tied down, and the left main wheel was chocked. The left door was open and the magneto switch was in the "Both" position. The pilot's right shoe was on the right side of the airplane, forward of the propeller. A trail of blood led from the front of the airplane to the passenger side of the pilot's vehicle. The pilot was initially hospitalized with serious head injuries and subsequently died on January 2, 2004. Federal Aviation Administration publication, Preventing Accidents During Aircraft Ground Operations (FAA-P-8740-20), presents suggestions to aid in increasing the safety factor while hand starting airplanes. The publication states the following: "No one should attempt to start an aircraft engine without a qualified person at the cockpit controls. The person turning the propeller should be properly trained in the technique of hand cranking. If you have in mind to try hand propping by yourself - DON'T. If you must hand prop - get qualified help to position the engine controls and switches during the starting procedure. If hand propping can be avoided - DO." "Unsupervised 'hand propping' of an airplane should not be attempted by inexperienced persons. Regardless of the experience level, it should never be attempted by anyone without adhering to adequate safety measures. Uninformed or inexperienced persons or non-pilot passengers should never handle the throttle, brakes, or switches during starting procedures. The airplane should be securely chocked or tied down, and great care should be exercised in setting the throttle. It may be well to turn the fuel selector valve to the 'off' position after properly priming the engine and prior to actually attempting the hand start. After it starts, the engine will usually run long enough with the fuel 'off' to permit walking around the propeller and turning the fuel selector to the 'on' position."