Trapezoid Visual Illusion in Airplane Landings
In daylight, when approaching a runway for a landing in a small plane the runway appears to look like a trapezoid. When landing at a small airport we fly a pattern that looks like a elongated rectangle that consists of "downwind leg", "base leg" and "final approach leg."
The "final approach leg" is important for several reasons.
- We learn to start the approach at a specific altitude.
- We learn to begin the turn, into the "final approach" , at a distance and height from the end of the runway that allows our plane to land safely without increasing the power. (No dragging out the approach over several miles)
- We learn to visualize the shape of the trapezoid when everything is done right to enter our "final approach leg."
The safety lesson? What if we practice flying at night and test our abilities to land safely by performing several landings to practice and sharpen our skills.
The runway is outlined by lights. We can see the shape of the trapezoid at night. We are familiar with how it looks. Like an old friend.
Heres the illusion. What if we fly into a larger airport where the runway is twice as long and twice as wide and we are cleared for a "straight in" final approach from one mile away to the end of the runway?
The runway has the same shape. We are at the proper altitude on final approach and we begin to cut our power just like we did back at our old familiar home base airport for this night approach.
Think about this illusion. Where will we actually land?
Thats right, we will land far short of the end of the larger airports runway. The shape of the outline of the larger runway will appear to match the size and shape of the small runway where you practiced. Thats the illusion.
We are deceived and the result is a crash landing if don't recognize our mistake in time.
