Stephan Hall, Honeywell test engineer, and Calvin Blaser, Honeywell customer support engineer, attach thermalcouplers inside the auxiliary power unit bay of an A-10 Thunderbolt II June 23, 2021 at Hill Air Force Base, Utah. The thermalcouplers will determine temperatures inside the bay during a ground test. (U.S. Air Force photo by Cynthia Griggs)