Chief Master Sgt. Al Mast, KC-135 Boom Operator with Iowa Air National Guard’s 185th Air Refueling Wing flew his final flight on October 18, 2019 at the Sioux City, Iowa based Air Guard unit. Mast is retiring from the Air Guard after serving 30 years. Mast said he originally enlisted on October 18, 1989. U.S. Air National Guard photo by Senior Master Sgt. Vincent De Groot