Senior Airman Shanna Thomas, 779th Aerospace Medicine Squadron inside observer, helps a student who has passed the “time of useful consciousness” make the proper corrections to stop hypoxia Nov. 2. The “time of useful consciousness” is the period of time from the interruption of the oxygen supply, or exposure to an oxygen-poor environment, to the time when useful function is lost and the individual is no longer capable of taking proper corrective and protective action to prevent hypoxia. If a student cannot perform the corrective action, the student fails the hypobaric chamber test. (U.S. Air Force photo/Senior Airman Perry Aston)