Aviation Boatswain's Mate (Fuel) 3rd Class Brad Porter, assigned to the amphibious assault ship USS Peleliu (LHA 5), hoists a component of a centrifugal purifier during the Shipboard Aviation Fuels Refresher course held at the Center for Naval Aviation Technical Training Unit on Naval Air Station North Island. The 10-day course is held as a refresher course for sailors in the aviation community. (U.S. Navy photo by Mass Communication Specialist 3rd Class Stacy Atkins Ricks/Released)