U.S. Air Force Senior Airman Michael Smith, 1st Maintenance Squadron aerospace propulsion technician, checks an F-22 Raptor engine for leaks during an engine run at Langley Air Force Base, Va., July 22, 2015. Smith inspects the engine after each test to ensure no further repairs are required. (U.S Air Force photo by Airman 1st Class Derek Seifert/Released)