Airman 1st Class Christopher Thomas and Senior Airman Adam Reinert, 28th Maintenance Squadron aerospace propulsion mechanics, clean and inspect second stage engine blades for foreign-object damage at the propulsion flight building on Ellsworth Air Force Base, S.D., Nov. 29, 2011. If blades are dinged, nicked or scratched, the mechanics remove, repair and reinstall them in the engine. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)