U.S. Air Force Col. David Carlson salutes U.S. Air Force Col. Gregory Guillot, 55th Wing commander, after assuming command of the 55th Maintenance Group during a change of command ceremony July 9 in Dock 1 of the Bennie Davis Maintenance Facility at Offutt Air Force Base, Neb. Carlson took command from U.S. Air Force Col. Daniel Courtois, who had led the group since June 2010. (U.S. Air Force photo by Charles Haymond/Released)