Senior Airmen Kristopher Benfer and Fernando Cardenas, crew chiefs with the 1st Special Operations Aircraft Maintenance Squadron, start the auxiliary power unit on an AC-130U Spooky Gunship at Hurlburt Field, Fla., Dec. 15, 2015. Primary missions of the AC-130U are close air support, air interdiction and armed reconnaissance. (U.S. Air Force photo by Senior Airman Meagan Schutter)