U.S. Air Force Tech. Sgt. Jennifer Kernan, 633rd Aerospace Medicine Squadron flight chief, practices training Senior Airman Mason Wyman, 633rd AMDS physiology technician, on a Reduced Oxygen Breathing Device at Langley Air Force Base, Va., Dec. 11, 2014. The ROBDs can replicate the F-22 Raptor and T-38 Talon, among other planes, to accommodate different training objectives for U.S. military pilots and air crew members from the Hampton Roads area. (U.S. Air Force photo by Airman 1st Class Devin Scott Michaels/Released)