 Tom Wolfe's book "The Right Stuff" referred to this claim, but referred to another test pilot, Geoffrey de Havilland, Jr., who had been killed in a previous test flight, when his DH 108 broke up at about Mach 0.9.As a demonstration pilot, Derry developed a new type of aerobatic manoeuvre which became known as the "Derry Turn".It consists of a reversal of bank during a steep turn which is performed with the aircraft passing through the inverted rather than upright attitude.