Oct 1st 1969, Concorde 001 breaks through the sound barrier for the first time.

On 1st October 1969, Concorde 001 broke through the sound barrier for the first time. Among other crucial tests, the engineers conducted flutter tests, to ensure the airframe could handle high-speed vibrations without the risk of structural failure.

The airliner cruised at 36,000ft., approximately 75 miles, and then reached Mach 1.05 (805 mph) for 9 minutes before slowing back to its subsonic speed.

A little over a year later, the aircraft flew twice the speed of sound, at Mach 2 (1,350 mph) in November 1970. It had been upgraded with Olympus 593B engines, to allow it to fly at Mach 2 for longer distances.