Which statement best describes Indicated Airspeed (IAS)?

• A. Shown on the dial of the instrument airspeed indicator, uncorrected for instrument and position errors.
• B. Corrected for instrument errors only; IAS equals CAS.
• C. True airspeed corrected for altitude and temperature.
• D. Ground speed as indicated by GPS.

Answer: (A)

Indicated Airspeed is the speed read directly from the airspeed indicator. It comes from the dynamic pressure sensed by the pitot-static system but is not corrected for errors in the instrument itself or for the position of the sensor on the aircraft. That raw reading is what the instrument shows, making it uncorrected for instrument and position errors. If you corrected for those errors, you’d get calibrated airspeed; if you corrected for altitude and temperature, you’d get true airspeed; and ground speed is a separate measure of speed over the ground, not through the air. So the statement that IAS is what’s shown on the dial, uncorrected for instrument and position errors, is the correct description.