Airman Adrihn Tenakoun, left, and Airman Alex Walker, 364th Training Squadron electrical and environmental systems apprentice course students, work on an F-15 Eagle at Sheppard Air Force Base, Texas, Oct. 5, 2018. Tenakoun and Walker are removing and installing a bleeder check valve as part of their training at Sheppard. The E&E training consists of students removing and replacing several components around the aircraft multiple times until they are proficient in each. (U.S. Air Force photo by Airman 1st Class Pedro Tenorio)