Staff Sgt. Matthew Duck, 7th Airlift Squadron loadmaster, tests the functionality of his aircrew eye and respiratory protection system while flying in a C-17 Globemaster III near Moses Lake, Wash., June 6, 2018. Duck was participating in Exercise Rainier War, which provided insights on how to better execute a tactical scenario for possible future conflicts. (U.S. Air Force photo by Senior Airman Tryphena Mayhugh)