Airman 1st Class Elias Conkel (left) and Airman 1st Class Casey McNamara perform maintenance on the engine of a KC-135 Stratotanker February 15, 2017 at Rickenbacker Air National Guard Base. The aircraft had just returned from receiving depot level maintenance at Tinker Air Force Base, Oklahoma. (U.S. Air National Guard photo by Senior Master Sgt. Ralph Branson)