Crew chiefs from the U.S. Army 160th Special Operations Aviation Regiment wait for Special Forces Soldiers to board the CH-47th Chinook during helocast training as part of Emerald Warrior at Hurlburt Field, Fla., April 21, 2015. Emerald Warrior is the Department of Defense's only irregular warfare exercise, allowing joint and combined partners to train together and prepare for real-world contingency operations. (U.S. Air Force photo by Staff Sgt. Kenneth W. Norman/Released)