Capt. Joel Oyama, 446th Aeromedical Evacuation Squadron flight nurse, checks out a Quick Don oxygen mask at the Aviation Survival Training Center, Naval base Whidbey Island, Wash., Nov. 9, 2011. ASTC is where McChord Field aircrew members currently receive their high-altitude chamber refresher training. (U.S. Air Force photo/Master Sgt. Jake Chappelle)