ELLSWORTH AIR FORCE BASE, S.D. – Airman 1st Class Rodney Lewis, 28th Logistics Readiness vehicle and vehicular equipment maintenance journeyman, replaces the air filter on a bobtail truck, July 16. Airman Lewis is preparing the bobtail for the upcoming operational readiness exercise. (U.S. Air Force Photo/Airman 1st Class Corey Hook)