Chuck Yeager

On 14 October 1947 he piloted the Bell X-1 to Mach 1.06 at 43,000 feet over the California desert, the first flight faster than the speed of sound, which the Smithsonian says showed that aircraft could be designed to fly faster than sound and turned the 'sound barrier' into a myth.

He shared the 1947 Collier Trophy with Bell Aircraft's Lawrence Bell and NACA scientist John Stack for the first supersonic flight, a joint NACA and Army Air Forces research programme.

He kept pushing the speed envelope, reaching Mach 1.45 in the X-1 in March 1948 and Mach 2.44 in the X-1A in December 1953, a flight that ended in a violent tumble from which he recovered.

Two days before the Mach 1 attempt he broke two ribs in a fall from a horse and, according to the officer in charge, said nothing; a broom handle was used as a lever extension so he could close and lock the X-1's hatch.

This is consistent with a willingness to accept personal risk, and to work around a physical obstacle, rather than give up a flight he had prepared for. Risk Tolerance

After the X-1A tumbled out of control at Mach 2.4 in December 1953, he told fellow test pilot Scott Crossfield he had deliberately put it into a spin in thicker air, saying a spin was something he knew how to get out of.

This is consistent with falling back on a manoeuvre he knew well to recover an aircraft in a situation no one had a procedure for. Resourcefulness

In 1947 the Air Force took over the X-1 project after Bell's civilian pilot demanded large bonus money to go past Mach 1, and Colonel Albert Boyd chose Yeager, then the most junior test pilot available, who flew it for his regular captain's pay.

This is consistent with accepting a high-stakes, unproven assignment that a better-paid civilian pilot had stalled over. Risk Tolerance