Airman 1st Class William Becker, 28th Aircraft Maintenance Squadron B-1 bomber crew chief, prepares to check the air pressure of a B-1 tire during a pre-flight inspection at Ellsworth Air Force Base, S.D., Sept. 10, 2013. Crew chiefs at Ellsworth are responsible for maintaining 27 assigned B-1 aircraft valued at more than $7.6 billion. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)