U.S. Air Force Master Sgt. Brian Greer, a 77 ARS boom operator, opens the boom window on a KC-135 Stratotanker before takeoff from the flightline on Seymour Johnson Air Force Base, North Carolina, Dec. 5, 2019. Opening the boom window is part of a boom operator’s pre-flight checks on a KC-135. (U.S. Air Force photo by Staff Sgt. Mary McKnight)