Bryon Harrington, a test engineer for the Propulsion Test Branch, Test Division, Arnold Engineering Development Complex, stands in front of an F100 engine outside of the Engine Test Facility at Arnold Air Force Base, Tenn., Dec. 4, 2020. When Harrington was an enlisted Airman in the U.S. Air Force he serviced and removed F100 engines. He now works as a civilian for an organization which has performed ground testing on the engine. (U.S. Air Force photo by Jill Pickett)