Senior Airman Kymric Walker, 28th Maintenance Squadron aerospace propulsion technician, takes apart the mixing duct on a B-1 engine during routine maintenance at Ellsworth Air Force Base, S.D., March 21, 2012. The mixing duct was deemed unserviceable during an engine inspection. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)