28 September 1954 – The 4th of 13 North American X-10’s, on Navaho X-10 flight number 10, a structural test flight, successfully made extreme maneuvers at Mach 1.84.
On # 4’s flight, the automated landing system attempted to make a landing flare 6m below the runway level at Edwards AFB, California. The vehicle impacted at high speed and was destroyed. However, the flight set a speed record for a turbojet-powered aircraft.
From 1953 to 1955 a total of five X-10s flew 15 flights at Edwards AFB. The 4th X-10 reached a maximum flight speed of Mach 1.84, flew a distance of 400 mi (644 km), and reached an altitude of 41,000 feet (12,000 m). These were performance levels superior to nearly all manned turbojet aircraft (the exception being the YF-104 Starfighter).
Of all the X-10s built, only one survived the test program: serial 51-9307, the first X-10 to fly.