true air speed


Also found in: Acronyms.

true air speed (TAS)

true air speed (TAS)click for a larger image
Relationship between IAS and TAS at various heights.
The actual speed of an aircraft relative to the air through which it flies (i.e., the calibrated air speed corrected for temperature, density, and compressibility). If the compressibility effects are ignored, then the IAS equals the product of the TAS and the square root of the relative density. Similarly, the TAS is related to the Mach number by the square root of the relative temperature.
References in periodicals archive ?
The speed corresponds to 815 knots true air speed and Mach 1.
So far the helicopter has exceeded 20,000 feet in altitude and 172 knots true air speed.
It possesses a maximum sea-level cruise speed of 271 knots true air speed and a maximum climb rate of 4,100 feet per minute.