British Royal Air Force Flight Lt. Clement Cornish, a flight safety officer with 903 Expeditionary Air Wing, throws a smoke grenade during a training exercise at Camp Leatherneck, Helmand province, Afghanistan, April 27, 2013. The exercise was conducted to keep service members prepared in the event of downed aircraft. (U.S. Marine Corps photo by Cpl. Ashley E. Santy/Released)