U.S. Air Force Airman First Class David Mannarino, a crew chief from the 140th Aircraft Maintenance Squadron, adds nitrogen to a tire of an F-16 Fighting Falcon during an Operational Readiness Exercise at Buckley Air Force Base Colo., January 20, 2012. Buckley Air National Guard airmen are taking part in the ORE being held on base throughout the weekend. The exercise evaluates airmen with mission readiness in preparation for real world deployments as well the Operational Readiness Inspection being held in the spring. (U.S. Air Force photo by Wolfram M. Stumpf /RELEASED)