Marines with Marine Medium Tiltrotor Squadron 261 (Reinforced), 24th Marine Expeditionary Unit, stand by as an AV-8B Harrier prepares to conduct night operations aboard the USS Iwo Jima, July 21, 2012. The night crews of the Aviation Combat Element, or ACE, ensure maintenance and operations are conducted safely every evening while many of their fellow Marines have already secured for the day. The Harrier detachment of the ACE is from Marine Attack Squadron 542 based out of Marine Corps Air Station Cherry Point, N.C. The 24th MEU is deployed with the Iwo Jima Amphibious Ready Group as a theater reserve force for U.S. Central Command. The group is providing support for maritime security operations and theater security cooperation efforts in the U.S. Navy's 5th Fleet area of responsibility.