Senior Airman Brooke Parks, 555th Aircraft Maintenance Unit F-16 Fighting Falcon crew chief, replaces a tire on a U.S. Air Force F-16 Fighting Falcon at Graf Ignatievo Air Base, Bulgaria, July 9, 2021. Duties of a crew chief include overseeing daily maintenance, identifying malfunctions and replacing parts, conducting inspections and maintaining records, and coordinating aircraft care. (U.S. Air Force photo by Airman 1st Class Brooke Moeder)