U.S. Air Force Col. David Leedom, Reserve Advisor to the 8th Air Force commander, presents Lt. Col. Tim Mers with a certificate of retirement on June 26, 2015 at Barksdale Air Force Base, La. Colonel Mers was an Instructor Weapons System Officer for the 93rd Bomb Squadron and is retiring with over 30 years of honorable service. (U.S. Air Force photo by Master Sgt. Laura Siebert/Released)