For heroism while engaged in aerial flight in connection with military operations against a hostile force, while serving as the Aircraft Commander of a UH-1 helicopter. Warrant Officer Canfield distinguished himself during an airmobile operation lifting friendly elements into landing zones west of Quang Ngai. He received word that an OH-23 helicopter had been shot down just north of the operations area. Unhesitatingly he flew his ship to the vicinity of the crash to ascertain the location of survivors and to cover the rescue attempt. Making low level passes, he spotted and reported the location of the surviving crewman and noted likely locations of enemy. Making continuous passes, his ship poured forth an amazingly heavy volume of fire, keeping the enemy pinned down and allowing the rescue ship to extract the seriously wounded crewman. He continued his close-in support and cover until the rescue ship had departed the area. His professional skill and personal courage contributed immeasurably to the success of the mission. His action was in keeping with the highest traditions of the military service and reflect the utmost credit upon himself, his unit, and the United States Army.