The refueling boom of a U.S. Air Force KC-135 Stratotanker aircraft assigned to the 507th Air Refueling Wing awaits an F-16 Fighting Falcon aircraft, background, before conducting an aerial refueling near Hawaii July 26, 2014, during Rim of the Pacific 2014. RIMPAC is a U.S. Pacific Fleet-hosted biennial multinational maritime exercise designed to foster and sustain international cooperation on the security of the world's oceans.