Senior Airman William Olson, 28th Operations Support Squadron air traffic control journeyman, changes the airfield lighting configuration for current wind conditions in the ATC tower on Ellsworth Air Force Base, S.D. April 3, 2012. Wind conditions determine the direction aircrews will take-off and land. The runway lighting controlled by ATC helps to ensure everyone is aware of the current correct direction. (U.S. Air Force photo by Airman 1st Class Kate Thornton/Released)