Breathe in, breathe out
ROYAL AIR FORCE LAKENHEATH, England - Capt. Ashley Thomas, 48th Aerospace Medicine Squadron aerospace and operational physiology officer in charge, briefs Lt. Col. Jonathan Taylor, 494th Fighter Squadron director of operations, before training in the Reduced Oxygen Breathing Device/Hypoxia Familiarization Trainer, Nov. 18, 2011. The trainer provides aircrew members the ability to still experience a simulated altitude change without the added pressure changes and risks when using an altitude chamber. (U.S. Air Force photo by Senior Airman Lausanne Morgan)