Definition of Mach
Mach is a dimensionless unit used in aeronautics and aviation to denote the ratio of an aircraft’s speed to the speed of sound in the medium through which it is flying. It is a measure of airspeed against the speed of sound and is calculated as the ratio of True airspeed to the speed of sound at the altitude of a given flight.
If an aircraft is flying at a Mach number of 0.75, it means that it is traveling at 75% of the speed of sound. The Mach number is used to describe the speed of aircraft that are in the subsonic, transonic, supersonic, hypersonic, high-hypersonic, and re-entry speed ranges.
Commercial flights, at present, are all subsonic flights as they are designed to operate below the speed of sound. The Mach number is crucial to understanding aircraft performance and behavior under various speed conditions.
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