U.S. Air Force Tech Sgt. Jennifer Greer from the 446th Civil Engineer Squadron uses surveying equipment to calculate the height of a base water tower during a field exercise at Tyndall Air Force Base, Fla. on May 26, 2011. Sergeant Greer is one of 30 Reservists from the 446th CES participating in Silver Flag 2011, a week-long training exercise designed to improve the readiness capability of Air Force civil engineers. Sergeant Greer, of Puyallup, Wash., is an engineering craftsman with the 446th CES. (U.S. Air Force photo by Staff Sgt. Grant Saylor/Released)