by Harold Green
Copyright 2021. All rights reserved!
Published in Midwest Flyer Magazine – print & online April/May 2021 issue
Most of us who have been flying for a while have found ourselves with landing problems. All at once we are either flying the silly thing too close to the ground before suddenly rotating with an attendant porpoising, or we stall out several feet in the air, testing the integrity of the landing gear. And sometimes we misjudge the touch-down point. So, what can cause this?
There is no elegant research which I am aware of that provides a foundation for landing issues. The following is just one instructor’s perspective on the issue. Note that ground control after landing is one of the principal causes of accidents but will be left as the subject for another article.
One of the most common causes of landing problems is a change in eyeglasses. Sometimes a seemingly insignificant change in the center of the lens can affect our depth perception. The effect is a change in the apparent height of the aircraft above the runway, and a change in the perceived touchdown point. Along those same lines, the first time a pilot wears bifocals can have a significant change in his depth perception.
Some of us learned early on that progressive lenses prevent an erroneous horizon line, particularly in instrument flight, as well as upon landing. That demarcation line can cause a grave error in perceived bank angle, changing with the angle of one’s head.
The brain interprets the visual information and produces an image of what will happen based not just on what we are focused on, but peripheral images as well. That includes the rate of change of that information. Thus, when watching the runway, or any other view ahead, the brain puts together a picture, including the cowling, the windshield supports, the instrument panel eyebrow and any other elements which the brain picks out and their relationship with one another. All components are put together, along with the apparent change in the ground view, to form an estimate of the aircraft’s future position. Once a pilot learns to maintain the proper visual image or perspective, landings become acceptable or at least better. Therefore, whatever you do to change your position relative to any of these elements will affect your prediction of aircraft track. Things that produce changes include the height or position of the seat, the number of cushions one uses, a change in the height of the instrument panel brow, etc. So, if your landings have gone south on you, review all of the above.
Now the effect of all of these things can be exacerbated by focusing too close on the aircraft, rather than looking far ahead. Remember when your instructor used to yell at you, “You’re looking too close to the plane, darn it?” The reason is you can’t judge height by looking too close. You need the perspective provided by looking ahead. Your brain actually forms a view that can be likened to an instrument using the lines of perspective, formed by the edge of the runway, the horizon, etc. There is a lot more to this than just the little discussion here, but this will suffice to make the point.
Another, and very important factor, is the stability of your approach. If the approach is stable, it means that the visual signals your brain receives are changing in a predictable fashion and you automatically predict your path. If your speed, altitude – and particularly attitude – change frequently, your brain cannot process the visual information properly and you won’t be able to accurately rotate or hold attitude for landing.
When rotating, just make sure you maintain the proper attitude for your aircraft until it touches down. It never works to force the aircraft onto the runway. The key is to let the aircraft land itself. The most you can do is establish the conditions your aircraft needs to do what you want.
So, what do we do when our usual smooth, barely-feel-the-touchdown-landings go away?
First, look for what has changed. Check to see that the proper visual point is maintained.
Recall the emphasis on stabilized approaches? Well, make sure your approach is stabilized. Remember that a good landing is dependent on a stable, consistent approach. The main corrective factor here is “practice,” and one might have a flight instructor observe and assist. Up to this point, it doesn’t matter whether you are flying a tail-wheel aircraft or one with the training wheel up front. Once on the ground, things change a bit and that will be the topic for a future column.
EDITOR’S NOTE: Harold Green is an Instrument and Multi-Engine Instrument Instructor (CFII, MEII) at Morey Airplane Company in Middleton, Wisconsin (C29). A flight instructor since 1976, Green was named “Flight Instructor of the Year” by the Federal Aviation Administration in 2011 and is a recipient of the “Wright Brothers Master Pilot Award.” Questions, comments and suggestions for future topics are welcomed via email at firstname.lastname@example.org, or by telephone at 608-836-1711 (www.MoreyAirport.com).
DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of their personal flight instructor and others, and refer to the Federal Aviation Regulations, FAA Aeronautical Information Manual and instructional materials before attempting any procedures discussed herein.