The National Aeronautics and Space Administration (NASA) has flight-tested a flush airdata sensing (FADS) system on the Hyper-X Research Vehicle (X-43A) at hypersonic speeds during the course of two successful flights. For this series of tests, the FADS system was calibrated to operate between Mach 3 and Mach 8, and flight test data was collected between Mach 1 and Mach 10. The FADS system acquired pressure data from surfacemounted ports and generated a real-time angle-of-attack ( ! ) estimate on board the X-43A. The collected data were primarily intended to evaluate the FADS system performance, and the estimated ! was used by the flight control algorithms on the X-43A for only a portion of the first successful flight. This paper provides an overview of the FADS system and ! = port 2 pressure reading, psf P 3 = port 3 pressure reading, psf P 4 = port 4 pressure reading, psf P 5 = port 5 pressure reading, psf psf = pounds per square foot scramjet = supersonic combustion ramjet TPS = thermal protection system X/L = fraction of reference length q = dynamic pressure, psf ! = angle of attack, deg ! = angle of sideslip, deg