Capt. David Cox flies an aircraft simulator during simulated hypoxia training Sept. 17, 2014, at Royal Air Force Station Lakenheath, England. Every five years, aircrew are required to undergo hypoxia familiarization training to reintroduce them to signs and symptoms of hypoxia. Cox is the 100th Operations Group training assistant chief. (U.S. Air Force photo/Airman 1st Class Erin O’Shea)