The airplane abruptly moved forward and contacted the pilot while he was attempting to start the engine by hand. During a telephone interview with a National Transportation Safety Board investigator, the pilot stated that he had flown to the airport earlier in the day. He intended to depart back to his home-airport and attempted to start the engine by rotating the propeller by hand, as he had done many times previously. The engine started abruptly and the airplane lurched forward. The propeller contacted the left side of the pilot's body, severing his left arm. The pilot further stated that he had accidentally positioned the throttle control in the full open (on) position, which resulted in the sudden movement; he had not secured the airplane prior to the start-up attempt. He reported no mechanical malfunctions or failures with the airframe or engine. The pilot had over 1,500 hours in the accident airplane. 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."