ARNOLD AIR FORCE BASE, Tenn. --   1st Lt. Adam Doyle, second from left, a test manager in the Propulsion Test Branch, Test Division, Arnold Engineering Development Complex (AEDC), briefs Rep. John Rose, of Tennessee, about the engine testing conducted using the Sea Level Test Cell 3 (SL-3) as they tour the facility during the representative's visit to Arnold Air Force Base, Tenn., headquarters of AEDC, Aug. 31, 2021. An F135, the engine that powers the F-35 Joint Strike Fighter, is currently installed in SL-3 for accelerated mission testing. (U.S. Air Force photo by Jill Pickett)