U.S. Air Force Staff Sgt. Brian (front) and Staff Sgt. Houston, 447th Expeditionary Aircraft Maintenance Squadron crew chiefs, perform initial preflight checks on a KC-135 Stratotanker Nov. 2, 2016, at Incirlik Air Base, Turkey. Preflight checks allow for air and ground crews to ensure there are no issues with the aircraft before flight. (U.S. Air Force photo by Staff Sgt. Jack Sanders)