What are the three types of airspeed?

• A. Dynamic, Static, Total
• B. Mach, TAS, CAS
• C. Indicated, Calibrated, True
• D. Relative, Absolute, Ground

Answer: (C)

Speed is interpreted in stages because the air the airplane moves through isn’t uniform and instruments have imperfections. The first reading, indicated airspeed, comes directly from the airspeed indicator and reflects dynamic pressure in the pitot system. It isn’t corrected for instrument or installation errors, so it’s not the exact speed through the air.

Calibrated airspeed takes that raw reading and removes those known instrument and position errors. It gives a more accurate speed through the air as if the pitot system were perfectly located and calibrated, but it still doesn’t account for changes in air density with altitude.

True airspeed goes a step further and corrects for density (and, at higher speeds, compressibility effects). This is the speed of the aircraft through the actual air mass, which means TAS changes with altitude even if CAS stays the same.

So, the three types are indicated airspeed, calibrated airspeed, and true airspeed. The other groupings mix different concepts (like pressure terms or wind-related speeds) and don’t represent the standard sequence of airspeed definitions.