What is absolute altitude?

• A. The vertical distance of the aircraft above the surface.
• B. The vertical distance of the aircraft above sea level.
• C. The vertical distance of the aircraft below the surface.
• D. The vertical distance of the aircraft above the cloud layer.

Answer: (A)

Absolute altitude is the vertical distance of the aircraft above the surface beneath it. In other words, it’s how high you’re above the terrain directly below you, not above sea level. This is important for terrain clearance and safe flight over varied ground, and it’s effectively the same idea as height above the ground (AGL) used in gliding. It differs from height above mean sea level (altitude or true altitude) and isn’t about distance above a cloud layer.