U.S. Marines part of a quick reaction force (QRF); assigned to Marine Wing Support Squadron (MWSS) 271, conduct a defense of an expeditionary airfield (DEAF) exercise during Weapons and Tactics Instructor Course (WTI) 2-15 at Landing Zone Bull at Chocolate Mountain Aerial Gunnery Range, Calif., April 10, 2015. WTI is a seven-week event hosted by Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) cadre. MAWTS-1 provides standardized tactical training and certification of unit instructor qualifications to support Marine aviation Training and Readiness and assists in developing and employing aviation weapons and tactics. (U.S. Marine Corps photo by Lance Cpl. Jodson B. Graves, 2d MAW Combat Camera/Released)