The first YF-16 (#72-1567) was rebuilt in December of 1975 to become the USAF Flight Dynamics Laboratory's Control Configured Vehicle (CCV). CCV aircraft have independent or 'decoupled' flight control surfaces, which make it possible to maneuver in one plane without movement in another - for example, turning without having to bank. To achieve this, the aircraft's flight controls were modified and it was fitted with twin vertical canards underneath the air intake. First flight in the CCV role was on March 16th, 1976 and the tests lasted till July 31st, 1977. On June 24th, 1976 was damaged when the engine failed during a landing cycle. It was repaired but broken again in a hard landing in July of 1977. This cut the CCV tests short.