Tech. Sgt. Robert Jonas function checks an emergency oxygen mask Dec. 10, 2011 at Joint Base Charleston, S.C. Sergeant Jonas is a medical technician with the 315th Aeromedical Evacuation Squadron at JBC, and he is trained and equipped to provide in-flight medical care aboard the C-17 Globemaster III and other mission directed aircraft. (U.S. Air Force photo/Staff Sgt. Shane Ellis)