The first F-35 Lightning II with a Center Wing Assembly, or CWA, built at the Lockheed Martin facility in Marietta, Georgia, was flown at the Lockheed Martin facility in Fort Worth, Texas, on 6 March 2013 for the first time. The CWA is a major structural component and represents approximately one quarter of the aircraft’s fuselage. The aircraft’s wings are attached to the CWA during final assembly, which takes place in Fort Worth. The aircraft with the first Marietta-built CWA is designatied BF-25 (US Navy Bureau Number 168723) and is an F-35B short takeoff and vertical landing variant that will be delivered to Marine Fighter Attack Squadron 121 (VMFA-121) at MCAS Yuma, Arizona. Lockheed Martin test pilot Paul Hattendorf was at the controls for BF-25's first flight.