Height above average terrain

Okay kiddo, so have you ever played with a toy airplane or helicopter? You know how sometimes they fly really high in the sky? Well, when pilots are flying real airplanes or helicopters, they need to make sure they don't crash into things like mountains or tall buildings. One way they do this is by knowing how high they need to fly above the average height of the ground they're flying over.

And that's what "height above average terrain" means! It's a fancy way of saying how high a pilot needs to fly above the ground so they don't accidentally hit anything.

To figure out the average height of the ground, people take a bunch of measurements using something called a surveyor, which is like a special tool that can tell you how high something is. They take lots of measurements all over the area where the pilot will be flying and then add them all up and divide by how many measurements they took. That gives them the average height of the ground.

So if a pilot needs to fly at a height above the average terrain of 500 feet, for example, it means they need to be at least 500 feet above the ground they're flying over. That way they can make sure they don't hit anything and can fly safely.