Bryon Harrington, a test engineer for the Propulsion Test Branch, Test Division, Arnold Engineering Development Complex, stands outside the Sea Level Engine Test Cells at Arnold Air Force Base, Tenn., Dec. 4, 2020. Harrington served in the U.S. Air Force as a crew chief working on aircraft and engines. Now a test engineer himself, he shadowed a test engineer in the SL cells at Arnold when first learning the role. (U.S. Air Force photo by Jill Pickett)