Captain Clinnin was the pilot of a F4U-4B Corsair fighter with Marine Fighter Squadron 312, Marine Air Group 12, 1st Marine Air Wing. On January 17, 1952, while on a combat mission, his aircraft received a direct hit by anti-aircraft fire, went into a spin, crashed and burst into flames. He was listed as Missing in Action and was presumed dead on December 16, 1953. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.