U.S. Air Force Staff Sgt. Robert Clark directs the driver of an Army M142 High Mobility Artillery Rocket System as it unloads from a C-17 Globemaster III at Hurlburt Field, Fla., on April 25, 2013. The units are participating in exercise Emerald Warrior, an annual two-week joint/combined tactical exercise sponsored by U.S. Special Operations Command. Clark is a loadmaster with the 8th Airlift Squadron at Joint Base Lewis-McChord, Wash.