Gen. Paul Selva, Air Mobility Command commander, receives lessons on MacDill's Boom Operator Weapon Systems Trainer at MacDill Air Force Base, Fla., Sept. 27, 2013. The BOWST is a fully simulated, large-scale procedural trainer for aerial refueling with replicated aircraft systems, controls, and functions within a complete aircrew boom compartment. (U.S. Air Force photo/Airman 1st Class Ned T. Johnston)