U.S. Air Force airmen from the 113th Fighter Wing District of Columbia Air National Guard Washington, D.C., execute a foreign object debris walk at Natal Air Base, Natal, Brazil, Nov. 3, 2013. U.S. Air Force F-16 Fighting Falcon and KC-135 Stratotanker aircraft will be simulating a wide variety of events in a fictitious peacekeeping response scenario. (U.S. Air Force photo by Senior Airman Camilla Elizeu/Released)