Col. Mark Weatherington, 28th Bomb Wing commander, leads Airmen down the flightline during a foreign object and debris walk on Ellsworth Air Force Base, S.D., March 12, 2012. FOD walks ensure that all rocks, screws, or any misplaced items are cleared from the runway to prevent damage to aircraft engines. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)