362nd TRS crew chief course
Karl Abts, 362nd Training Squadron crew chief apprentice course instructor, shows his class how to ensure the X-valve on a C-130 Hercules is in the closed position at Sheppard Air Force Base, Texas, Jan 23, 2018. The X-valve is used to jettison fuel from the aircraft during flight when necessary. It is also the last valve in the fuel system and must be closed prior to fueling. Abts’ class is in block seven of 10 and scheduled to graduate Feb. 21. (U.S. Air Force photo by Alan R. Quevy)