Thracian Star 21; Bulgarian and U.S. Air Force strengthen interoperability
A U.S. Air Force F-16 Fighting Falcon crew chief assigned to the 555th Aircraft Maintenance Unit performs a pre-flight inspection on a U.S. Air Force F-16 intake at Graf Ignatievo Air Base, Bulgaria, July 13, 2021. Eight F-16s assigned to the 555th Fighter Squadron are participating in Thracian Star 21, a Bulgarian air force-led exercise aiming to maximize interoperability, combat effectiveness and survival awareness. (U.S. Air Force photo by Airman 1st Class Brooke Moeder)