Petty Officer 3rd Class Shawn Grothaus conducts preflight checks on an MH-60S Seahawk helicopter attached to Helicopter Sea Combat Squadron 23 on the flight deck of the amphibious assault ship USS Boxer (LHD 4) while the ship is underway in the Pacific Ocean on Dec. 7, 2010. The Boxer, the Boxer Amphibious Readiness Group and the 13th Marine Expeditionary Unit participated in a certification exercise to prepare for a 2011 deployment.