An old and damaged fuel tank alarm system is replaced and upgraded by civilian contractors and members of the 28th Civil Engineer Squadron on Ellsworth Air Force Base, S.D., Dec. 28, 2011. A new alarm system was installed to keep fuel secure and ready to be used by the 28th Bomb Wing’s B-1B fleet. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)