Tech. Sgt. Jennifer Rowles, 39th Operations Squadron tower watch supervisor, and Senior Airman Matthew Thornton, 39th OS air traffic control journeyman, discuss air traffic control procedures July 27, 2011, at Incirlik Air Base, Turkey. Air traffic controllers must take a monthly proficiency test to ensure they are knowledgeable about all rules and regulations. (U.S. Air Force photo/Senior Airman Anthony Sanchelli)(Released)