I did see two men killed in front of me in one afternoon: at the 1975 Reno National Air Races - a T-6 caught a wing on a pylon and crashed. My Dad knew the pilot, he was a pilot for Texas International where my Dad also worked as a crew chief. During the cleanup for that disaster a wing-walker went up during the impromptu intermission and when he tried to pick up a ribbon while inverted the plane caught a downdraft and went into the runway, but the pilot pulled up and went around to land while the wing-walker was dangling in the breeze from his harness. Both accidents and deaths within 45 minutes of each other.
