Air Force Maj. Chris Carden, cockpit, and Staff Sgt. Michael Zimmerman conduct preflight checks on an F-16 Fighting Falcon aircraft at Bagram Airfield, Afghanistan, before a combat sortie on Jan. 17, 2016. Carden is a pilot assigned to the 421st Expeditionary Fighter Squadron and Zimmerman is a crew chief assigned to the 455th Expeditionary Aircraft Maintenance Squadron. U.S. Air Force photo by Capt. Bryan Bouchard