A U.S. Marine Corps Sikorsky CH-53 Sea Stallion makes its approach during an external lift exercise in conjunction with Weapons and Tactics Instructor Course 2-18 in Yuma, Ariz., April 4, 2018. WTI is a seven-week training event hosted by Marine Aviation Weapons and Tactics Squadron 1 cadre, which emphasizes operational integration of the six functions of Marine Corps aviation in support of a Marine Air Ground Task Force and 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.