A Dornier Do328-300 converted into the Advanced Composite Cargo Aircraft Concept aircraft by Lockheed-Martin and first flew as such on 2nd June 2009.

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.