Keywords: US Navy 110215-N-ZK021-005 Sailors huddle to account for their classmates as they complete the final dunk and lap swim exercise during a simulated.jpg en OAK HARBOR Wash Feb 15 2011 Sailors huddle to account for their classmates as they complete the final dunk and lap swim exercise during a simulated storm at the Aviation Survival Training Center ASTC at Naval Air Station Whidbey Island Students at ASTC go through a series of evolutions including a simulated helicopter crash parachute drags and survival techniques after exiting downed aircraft This two-day refresher course is mandatory every four years for anyone who flies in U S Navy and Marine Corps aircraft U S Navy photo by Mass Communication Specialist 2nd Class Nardel Gervacio/Released 2011-02-15 110215-N-ZK021-005 Navy http //www navy mil/view_image asp id 97652 U S Navy photo by Mass Communication Specialist 2nd Class Nardel Gervacio PD-USGov-Military-Navy Aviation Survival Training Center Whidbey Island Life rafts |