U.S. Army Chief Warrant Officer 2 Jordan Frizzell, 7th Battalion, 158th Aviation Regiment, shuts down a UH-60 Black Hawk after a medical evacuation mission during Exercise Vibrant Response at Camp Atterbury, Ind., Aug. 22, 2011. Vibrant Response is the largest chemical, biological, radiological and nuclear response exercise designed to prepare expeditionary units focused on responding to domestic CBRN incidents.