Airman 1st Michael D. Riley, 361st Training Squadron aerospace ground equipment apprentice course student, works on a self generation nitrogen service cart at Sheppard Air Force Base, Texas, June 14, 2019. It is important for Airmen to be proficient in this task so they can perform operational checks and keep aircraft ready for flight. Riley, a Colorado native, graduated the course with a 100% average, earning the ACE award. (U.S. Air Force photo by Airman 1st Class Madeleine E. Remillard)