U.S. Air Force Staff Sgt. Jack Olney, 633rd Civil Engineer Squadron heating, ventilation and air conditioning craftsman, uses the Rover system to repair an air conditioning fan coil at Langley Air Force Base, Va., Aug. 16, 2013. The Rover system was introduced eight months ago as a direct digital control system used to repair HVAC units. (U.S. Air Force photo by Staff Sgt. Ashley Hawkins/Released)