364th Training Squadron electrical and environmental systems apprentice course students work on an F-15 Eagle trainer jet at Sheppard Air Force Base, Texas, Dec. 6, 2018. During their stay here the students only learn the basic mechanical aspects of several different E&E systems. This gives them an understanding and allows them to focus on the fundamentals before learning all the different types of transformer rectifiers, de-fog systems, bleeder check valves, etc. (U.S. Air Force photo by Airman 1st Class Pedro Tenorio)