A 63rd Aircraft Maintenance Unit crew chief performs a systems evaluation on an F-35A Lightning II March 10, 2020, at Luke Air Force Base, Ariz. AMU crew chiefs ensure the aircraft they are assigned to are mission ready and prepared to fly. More than 90 F-35s assigned to Luke enable Airmen to complete the base’s mission to train the world’s greatest fighter pilots and combat ready Airmen. (U.S. Air Force photo by Airman 1st Class Brooke Moeder)