Staff Sgt. Manoel Robinson (center), boom operator from the 756th Air Refueling Squadron, Joint Base Andrews, Maryland, directs aerial porters from the 69th Aerial Port Squadron as part of his cargo checkride on Aug. 1, 2017. Boom operators are required to pass an annual cargo-loading and offloading evaluation on the KC-135R Stratotanker aircraft. (U.S. Air Force photo/Tech. Sgt. Erica J. Knight)