Airmen assigned to the 307th Maintenance Squadron prepare a B-52 Stratofortress for an engine run during a phase inspection of the bomber on Barksdale Air Force Base, La. June 29, 2017. It takes 19 different shops and around 25 days to complete the phase inspection with the engine run being one of the final parts. (U.S. Air Force photo by Master Sgt. Dachelle Melville/Released)