On June 25, 2006, about 1235 Pacific daylight time, a Cessna T210M, N761GW, was standing with the engine operating when the passenger egressed the airplane and contacted the propeller at Hayward Executive Airport, Hayward, California. Aerial Advertising Services was operating the airplane under the provisions of 14 CFR Part 91. The commercial pilot, who owned Aerial Advertising Services, was not injured; the passenger sustained fatal injuries. The airplane was not damaged. The personal local flight departed from Petaluma Municipal Airport, Petaluma, California, about 1200, with a planned destination of Hayward. Visual meteorological conditions prevailed, and a flight plan had not been filed. During a telephone interview with a National Transportation Safety Board investigator, the pilot stated that prior to the accident he and the passenger had flown to Petaluma to watch several of his airplanes perform banner-towing operations. After a brief stop, they flew back to Hayward to watch another banner-towing operation of an Aerial Advertising Service's airplane. The pilot landed the airplane on runway 28R and taxied across 28L to the ramp area. When arriving in the pad area he turned the airplane around, positioning the nose to face the runways. The pilot further stated that he was cooling down the turbocharged engine by maintaining low revolutions per minute (rpm), while keeping the airplane stationary. He planned to perform an approximate 5-minute cooling down period and then taxi the airplane to a parking area where he would shut down. After several minutes of the airplane standing, the passenger took off his headset and egressed the airplane. The pilot was not sure of the reasoning behind the passenger exiting the airplane but thought that he may have been getting impatient with the wait for the engine cool down. An airplane in the taxi area in front of N761GW reported to the Air Traffic Control (ATC) tower that that the passenger had been struck by the airplane's propeller. The pilot stated that the passenger was an experienced pilot; in recent years he mostly flew airplanes that were equipped with wing struts.