362nd Training Squadron F-16 crew chief apprentice course students watch a psi gauge at Sheppard Air Force Base, Texas, Sept. 9, 2019. The students are watching the gauge as their wingman pumps manually. Once the gauge tops off they will signal to their wingman to stop, the students will then take turns as this is one of their tasks during their training at Sheppard. (U.S. Air Force photo by Airman 1st Class Pedro Tenorio)