Staff Sgt. Richard Burton, 28th Aircraft Maintenance Squadron electro-environmental technician, installs a seal to a B-1 bleed air duct for a 1,800 day maintenance inspection during an Operational Readiness Exercise on Ellsworth Air Force Base, S.D., March 20, 2013. These day-specific inspections must be completed before an aircraft can continue to fly safely. (U.S. Air Force photo by Airman 1st Class Kate Thornton-Maurer/Released)