Airman 1st Class Aaron Barber, 28th Maintenance Squadron aerospace propulsion technician, cleans the base of a B-1 engine thermometer with denatured alcohol in an aircraft hangar on Ellsworth Air Force Base, S.D., July 19, 2012. Each engine is equipped with a thermometer that monitors the temperature inside the engine and relays information to the computer system in the cockpit. (U.S. Air Force photo by Airman Ashley J. Cass/Released)