Speckled Trout is the official nickname given to the modified C-135 used by the United States Air Force Chief of Staff. Fully equipped with an array of radio equipment, data links and cryptographic sets, the aircraft serves a secondary role as a testbed for proposed command and control systems. It is also used to evaluate future transport aircraft design. The 412th Flight Test Squadron at Edwards AFB, California, USA, operates the Speckled Trout and manages its test mission.