HOLLOMAN AIR FORCE BASE, N.M. – Lt. Col. Terrance C. Keithley, right, a test pilot for the 416th Flight Test Squadron at Edwards Air Force Base in Calif., receives pre-flight briefing information from an instructor pilot for the Beechcraft AT-6 experimental aircraft. The AT-6 is participating in the U.S. Air Force Light Attack Experiment (OA-X), a series of trials to determine the feasibility of using light aircraft in attack roles. (U.S. Air Force photo/Ethan D. Wagner)