Two crew chiefs from the 34th Aircraft Maintenance Unit, Ellsworth Air Force Base, S.D., perform maintenance on a B-1B Lancer assigned to the 34th Bomb Squadron, Ellsworth AFB, during Green Flag-West 15-02 at Nellis AFB, Nev., Nov. 18, 2014. Green Flag-West is a close air support exercise and ensures the highest level of integration between air and ground forces, and is administered by the U.S. Air Force Warfare Center and Nellis AFB through the 549th Combat Training Squadron. (U.S. Air Force photo by Staff Sgt. Siuta B. Ika)