Convert between true airspeed and Mach for any temperature, and see the local speed of sound that links them.
Convert between true airspeed and Mach for a given outside air temperature. Leave OAT blank and enter a pressure altitude to assume ISA. The local speed of sound depends only on temperature.
Enter a speed and a temperature (or a pressure altitude for ISA) to convert.
It depends only on temperature — about 38.97 × √(T in Kelvin) knots. Roughly 661.5 kt at sea-level ISA.
Climbing at a fixed IAS, TAS rises and the speed of sound falls, so Mach increases — the classic climb to the Mach/IAS crossover altitude.
Critical Mach, buffet, and high-speed handling all hang off this relationship. Get fluent with it for ATPL Principles of Flight.
Mach number is true airspeed divided by the local speed of sound. The speed of sound depends only on temperature: about 661.5 kt at 15 °C, falling as the air gets colder.
Yes. Switch the conversion direction, enter a Mach number and the temperature (or a pressure altitude to assume ISA), and SkyStudy returns the true airspeed.
Colder air higher up has a lower speed of sound, so the same true airspeed becomes a higher fraction of it — a higher Mach number.
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