In 2007, Lockheed Martin won the competition to build the Advanced Composite Cargo Aircraft (ACCA) for the Air Force Research Laboratory (badge on tail). Designated X-55 after first flight, Lockheed modified a Fairchild Dornier 328JET with a new advanced composite fuselage section constructed as a single large component which included the vertical fin replacing the original aft of the entrance door. Oval in section, the aft end was wider to allow cargo loading via a ramp and shortened the length by 14 feet. In 2014, the aircraft was placed on display at Joe Davies Heritage Airpark in Palmdale, CA.