True Airspeed is derived by correcting Calibrated Airspeed for altitude and nonstandard temperature. Which two conditions are included?

• A. Gusts and turbulence
• B. Altitude and nonstandard temperature
• C. Wind and humidity
• D. Pressure changes

Answer: (B)

True Airspeed accounts for how thick or thin the air is and how that density differs from standard conditions. The speed shown by the airspeed indicator is tied to dynamic pressure in the air, but this dynamic pressure depends on air density. As you climb, air becomes less dense, so for the same dynamic pressure the aircraft must move faster to achieve the same effect—hence TAS differs from CAS with altitude. Temperature also changes air density: if the air is warmer or cooler than standard, density changes and the relationship between indicated speed and actual speed shifts. So TAS is CAS corrected for how the air density changes with altitude and with nonstandard temperature.

Gusts, turbulence, wind, humidity, or pressure changes affect the readings or the environment in different ways, but the specific corrections to get true airspeed focus on altitude (density changes with height) and nonstandard temperature (density changes with temperature).