True Airspeed is the speed relative to the air and is CAS corrected for altitude and temperature. Which statement best reflects this?

True Airspeed is the speed relative to the air and is CAS corrected for altitude and temperature. Which statement best reflects this?

• A. Speed relative to the ground
• B. Calibrated Airspeed corrected for instrument errors
• C. True Airspeed is CAS corrected for altitude and temperature
• D. Indicated Airspeed reading

Answer: (C)

True Airspeed is the speed of the aircraft through the surrounding air, i.e., relative to the air itself. To get TAS you start with Calibrated Airspeed (IAS corrected for instrument and installation errors) and apply corrections for air density changes caused by altitude and temperature. As air becomes less dense with higher altitude or warmer temperatures, the same CAS corresponds to a higher true speed, so TAS increases relative to CAS. That relationship is why the statement that True Airspeed is CAS corrected for altitude and temperature best reflects TAS. Ground speed, by contrast, is TAS adjusted for wind, and Indicated or Calibrated airspeeds refer to readings with different corrections but not to motion through the air itself.

True Airspeed is the speed of the aircraft through the surrounding air, i.e., relative to the air itself. To get TAS you start with Calibrated Airspeed (IAS corrected for instrument and installation errors) and apply corrections for air density changes caused by altitude and temperature. As air becomes less dense with higher altitude or warmer temperatures, the same CAS corresponds to a higher true speed, so TAS increases relative to CAS. That relationship is why the statement that True Airspeed is CAS corrected for altitude and temperature best reflects TAS. Ground speed, by contrast, is TAS adjusted for wind, and Indicated or Calibrated airspeeds refer to readings with different corrections but not to motion through the air itself.