On July 25, 1995, about 1400 eastern daylight time, a bystander, who was a pilot, and who was assisting in starting the airplane, was struck by the propeller of a Cessna 172N, N2415J. The flight was originating at First Flight Airport, Kitty Hawk, North Carolina. The bystander was seriously injured. There were no injuries to the private pilot, nor his two passengers, and the airplane was not damaged. The airplane was operated by Carolina Air Services, Inc., under 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed. A flight plan was not filed for the personal flight. The pilot had rented the airplane and flown from New Bern, North Carolina, to Kitty Hawk. While sightseeing, the master switch was inadvertently left in the "on" position. When the pilot returned, the battery had insufficient output voltage to start the airplane. A local pilot agreed to help start the airplane by hand. According to the pilot of the accident flight, the bystander told him to place the master switch in the "on" or "off" position, when instructed, and call out its position in reply. The initial attempts to start the airplane were unsuccessful. The assisting pilot stepped to the cockpit door to verify that the master switch was in the "on" position. The accident pilot asked where the ignition switch should be, and was told to place the ignition switch in the "start" position, as normal. When released, the switch was in the "both" position. As the bystander moved the propeller again, the engine fired. His hand was struck and broken by the propeller.