What is a 'calibrated' altitude?

• A. An altitude corrected for instrument error, but not for position error.
• B. An altitude corrected for temperature.
• C. An altitude corrected for wind.
• D. An altitude corrected for both instrument and position errors.

Answer: (A)

Calibrated altitude is the altitude shown after removing the altimeter’s own instrument errors. The altimeter can read a bit high or low due to mechanical wear, calibration drift, leaks, or mounting imperfections. Correcting for those instrument errors gives calibrated altitude.

It does not account for position error, which comes from the nonuniform atmospheric pressure field around the aircraft. To get true altitude (height above mean sea level under actual pressure distribution), you would apply a separate correction for position error (and, if needed, temperature effects). The other options describe corrections that aren’t part of what calibrated altitude represents.