200130-N-UX312-0027 NORFOLK (Jan. 27, 2020) Sailors assigned to Aviation Survival Training Command, Norfolk operate a normobaric hypoxia trainer (NHT). An NHT allows for safer hypoxia training for pilots and aircrewman while providing a more realistic experience. (U.S. Navy photo by Mass Communication Specialist 2nd Class Matt Herbst/Released)