Airman 1st Class Jonathan Rodriguez, 28th Maintenance Squadron fuel systms apprentice, checks the levels in a fuel tank during fuel level testing inside the fuel cell hangar at Ellsworth Air Force Base, S.D., Nov. 8, 2012. Maintaining proper fuel levels is vital to keeping aircraft properly fueled. (U.S. Air Force by Airman 1st Class Anania Tekurio/Released)