Airman 1st Class Patrick Ayoung, 1st Special Operations Support Squadron air traffic control apprentice, uses a signal light gun at the base control tower on Hurlburt Field, Fla., July 17, 2014. Signal lights are used to direct planes, day or night, in case of a radio failure or if an aircraft is not equipped with a radio. (U.S. Air Force photo/Senior Airman Kentavist P. Brackin)