Senior Airmen John Abbott and Jordan Cotton, both maintainers assigned to the 20th Aircraft Maintanence Squadron, Shaw Air Force Base, S.C., perform a caliber test on an F-16 Fighting Falcon’s landing gear during Red Flag 15-4 at Nellis AFB, Nev., Aug. 19, 2015. The caliber test was performed to ensure the maintainers could successfully change the aircraft’s landing gear tire. (U.S. Air Force photo by Airman1st Class Rachel Loftis)