Crew chiefs from the 34th Aircraft Maintenance Unit perform a pre-flight inspection on a B-1B Lancer Nov. 18, 2014, during Green Flag-West 15-02 at Nellis Air Force Base, Nev. Green Flag is typically a joint exercise involving multi-role fighters and/or bomber squadrons, unmanned aircraft, electronic warfare aircraft and aerial refueling aircraft. (U.S. Air Force photo/Staff Sgt. Siuta B. Ika)