The actual height above mean sea level at which the aircraft is flying is called the:

• A. Aircraft altitude
• B. Indicated altitude
• C. True altitude
• D. Absolute altitude

Answer: (A)

Understanding altitude terms starts with what each reference measures. The actual vertical distance from the mean sea level to the aircraft is true altitude. That’s the true height above MSL, regardless of what the instrument shows or what the terrain is beneath you.

The instrument readout you see in the cockpit is indicated altitude, which depends on the altimeter setting (local pressure). If you set the local QNH, indicated altitude approximates true altitude under standard conditions, but deviations in temperature and pressure mean it won’t always match exactly.

Absolute altitude refers to height above the ground, not above mean sea level. And “aircraft altitude” isn’t a precise aviation term for a defined reference.

So, the height above mean sea level is true altitude.