Air Force Airman 1st Class Jon Barrett refers to his technical orders before he services an F-15 Eagle aircraft engine at Kadena Air Base, Japan, May 12, 2017. Barrett is an aerospace propulsion technician assigned to the 18th Component Maintenance Squadron. The technical orders list detailed tasks that must be completed by technicians and inspectors to ensure the aircraft will function properly. Air Force photo by Senior Airman John Linzmeier