Friday, November 13, 2009

Downwind Landings at Night - Visual Illusions

Downwind Landing at Night

In a much earlier post we talked about what happens if you use the runway lights in your peripheral vision, in a night landing, to judge your height above the runway before you flare out prior to landing.

What is the visual illusion, if you mistakenly land with the wind (downwind landing) at night? In this case, looking at the runway lights in your peripheral vision, the lights appear moving quite fast. This is due to the increase in the planes actual speed over the ground caused by the tail wind.

You may think you are closer to the ground than you actually are. If you are at an altitude of fifty feet AGL but the plane seems much lower, due to the illusion caused by the runway lights, you may flare to a landing too soon and too high.

Net effect is a possible stall, too soon, and you nose the plane down into the runway for your first accident report.

As always, visual illusions can create situations where an accident is possible if you are unaware of what is happening.

Please discuss these situations with your flight school instructor. You can also email me or leave a message for me on this blog to discuss theses visual illusions anytime.