Tech. Sgt. Ken Frederick, 919th Special Operations Aircraft Maintenance Squadron, stops to remove a piece of debris from the tarmac at Duke Field, Fla. Maintainers routinely perform mass "FOD walks" -- FOD is an acronym for foreign object damage -- to prevent foreign objects from potentially damaging aircraft and hampering the flying mission. (U.S. Air Force photo/Tech. Sgt. Jonathan McCallum)