Landing Craft, Air Cushions assigned to Assault Craft Unit 5 land on Red Beach during joint exercise Pacific Horizon 2015, Oct. 23. PH15 is a scenario-driven, simulation supported crisis response exercise designed to improve 1st Marine Expeditionary Brigade's and Expeditionary Strike Group 3's interoperability and strengthen Navy-Marine Corps relationships by conducting an in-stream Maritime Prepositioning Force offload of equipment, by providing host country civil-military security assistance, and by conducting infrastructure restoration support.