170409-N-XL056-097 PACIFIC OCEAN (April 9, 2017) Sailors aboard the fleet replenishment oiler USNS Yukon (T-AO 202) participate in a vertical replenishment-at-sea with an MH-60S Sea Hawk helicopter from the "Eightballers" of Helicopter Sea Combat Squadron (HSC) 8 and the aircraft carrier USS Nimitz (CVN 68). Nimitz is underway conducting a composite training unit exercise (COMPTUEX) with the Nimitz Carrier Strike Group in preparation for an upcoming deployment. COMPTUEX tests a carrier strike group's mission-readiness and ability to perform as an integrated unit through simulated real-world scenarios. (U.S. Navy photo by U.S. Navy Mass Communication Specialist Seaman Leon Wong/Released)