A crew chief assigned to the 28th Aircraft Maintenance Squadron prepares to perform a post-flight inspection on a B-1B Lancer on the flight line at Ellsworth Air Force Base, S.D., Dec. 4, 2018. In addition to the day-to-day maintenance, crew chiefs are responsible for diagnosing malfunctions and replacing components on the aircraft. (U.S. Air Force photo by Senior Airman Denise Jenson)