U.S. Air Force Staff Sgt. Corie Flores, 633rd Security Forces Squadron, Base Defense Operations Center operator and squad clear a mock control tower building during Combat Readiness Training at Langley Air Force Base, Va., June 27, 2016. Base security operations is one of eight blocks of instruction taught at CRT. (U.S. Air Force photo by/Tech. Sgt. Daylena S. Ricks)