Airman 1st Class Jonathan Rodriguez, 28th Maintenance Squadron fuel systems apprentice, attaches a liquid quantity caging interface unit to a fuel quantity sensing checkout during fuel level testing inside the fuel cell hangar at Ellsworth Air Force Base, S.D., Nov. 8, 2012. Proper fuel levels are critical to maintaining fuel orders during deployment and day-to-day missions. (U.S. Air Force photo by Airman 1st Class Anania Tekurio/Released)