U.S. Marine Corps Cpl. Ross Roby, a UH-1Y Venom crew chief, with Marine Light Attack Helicopter Squadron (HMLA) 367, Marine Aircraft Group 39, 3rd Marine Aircraft Wing, clears a GAU-21 .50- caliber heavy machine gun while conducting an offensive air support exercise during Weapons and Tactics Instructor (WTI) course at Landing Zone Bull Attack in Chocolate Mountain Aerial Gunnery Range, California, Sept. 30, 2019. WTI is a seven-week training event hosted by Marine Aviation Weapons and Tactics Squadron One (MAWTS-1), which emphasizes operational integration of the six functions of Marine Corps aviation in support of a Marine Air Ground Task Force. WTI also provides standardized advanced 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 Cpl. Lauren Brune)