Tuesday, April 23, 2013
The Eyes Have It
The difference between “looking” and “seeing”
When we're pulling the airplane level in ground effect, one visual method often used is to fixate on the far end of the runway for as long as we can see it. This works, but the information isn't as finite as it would be if we picked far, distant points on both sides of the runway and continually shifted our focus from one to the other. This triangulation gives us more exact visual information and forces our peripheral vision further to the side, so even more information is gathered.
It's important to know the difference between "looking" and "seeing." When scanning for traffic against a relatively featureless background, your eyes aren't picking out a specific point and may tend to focus short, a phenomenon called "eye myopia."
If for instance, while in flare, the airplane turns even slightly left, the point where the runway edge hits the cowling will move down the side of the cowling, and the visual triangle will get smaller. The point moves up if we turn right, and the fuzzy triangle in our left peripheral vision will get bigger (we "sense" the change more than seeing it).
While we're holding the aircraft off and it's settling into ground effect, the point moves up the side of the nose as the airplane moves. The visual triangle, however, remains pretty much the same size because our nose has moved neither left nor right.
That point is continually talking to us. If we're looking straight ahead and depending on our peripheral vision to tell us what's happening, our 20/100 vision field will include that point, and the information we receive from it will, at best, be an approximation.
The ability to direct our 20/20 visual cone at the exact points where the most accurate visual information is being generated is what defines our visual acuity. And our visual acuity is often what defines us as pilots. The old saying says, "You can't fix what you can't see," and no truer words were ever spoken.
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Labels: Decision Making, Features, Flight Training, Learn To Fly, Learning Center, Pilot Guide, Pilot Skills, Pilot Safety