Which statement best describes the relationship among indicated, calibrated, and true airspeed?

• A. Indicated airspeed is uncorrected; calibrated airspeed corrects for instrument and position; true airspeed corrects for altitude and nonstandard temperature (density changes)
• B. Indicated equals calibrated equals true
• C. Calibrated equals indicated
• D. True equals indicated

Answer: (A)

Indicated airspeed is the raw reading you see on the airspeed indicator, uncorrected for any errors. Calibrated airspeed removes those instrument and installation (position) errors, giving you the airspeed corrected for the way and where the instrument sits in the aircraft. True airspeed goes a step further by accounting for air density, which changes with altitude and temperature; as density changes, the same dynamic pressure means a different actual speed through the air, so TAS reflects that.

So the best description is that indicated airspeed is uncorrected, calibrated airspeed corrects for instrument and position errors, and true airspeed corrects for altitude-driven density changes (nonstandard temperature). The other statements imply no corrections or equate speeds that aren’t actually the same in flight conditions.