January 21, 2005

9:21 PM

I have no visual depth perception, and I would like to learn to fly an aircraft. I have already passed a FAA Class 3 physical, the only restriction being "Must wear glasses".

I'm looking for advice from any pilots/instructors here that have learned to fly without depth perception, or have taught someone without depth perception to fly. What modifications need to be made to a normal flight/ground school curriculum for a student pilot without depth perception?
posted by anonymous to (13 comments total)

You have no depth perception? Or you are just not confident in yours?

It seems to me that depth perception is pretty important when navigating in 3 dimensions. Yet, people with one eye learn to manage many activities. Perhaps it can be overcome. If you haven't done this yet, go to your local airport and take an introductory flight lesson. These are offered at many places at very low cost ($40-60) and could help give you an idea of how your vision works in the cockpit. Final approach to landing should be illuminating.
posted by Tubes at 10:52 PM on January 21, 2005

IANAP, but would guess that you should start learning to fly the plane using IFR - Instrument Flight Rules. Normally, pilots learn Visual Flight Rules (VFR) first, and only use IFR when the weather is bad enough to warrant it. Without depth perception, you might end up flying as though visibility is limited all the time.
posted by b1tr0t at 11:32 PM on January 21, 2005

Yes, yes, I know, this isn't the answer you're looking for, but:

Holy crap! You're allowed to fly a plane if you have NO depth perception?! It's difficult enough to catch a frisbee if you have no depth perception (try it with one eye closed); how would you manage to land a plane?

Seriously, from the information you give, this sounds like a bad career choice for you. No offense.
posted by Dr. Wu at 11:33 PM on January 21, 2005

If you have no depth perception, please do not learn how to fly airplanes. The concept is irresponsible. There are other things you can do.
posted by interrobang at 11:37 PM on January 21, 2005

Well, my son is at USAFA, and there, failing the depth perception test causes you to lose your PQ. (He failed one, then passed a more extensive one, whew.) So you may want to make sure you would be allowed to fly period.
posted by konolia at 11:38 PM on January 21, 2005

I'd suggest reading this, it's certainly possible to fly with no depth perception. Some of the tricks mentioned could be adapted. I've flown with vision worse that 20/200 for over 30 years, with essentially an addendum on my medical certificate and a statement of demonstrated ability.
posted by pjern at 11:54 PM on January 21, 2005

I have only one functional eye and can say I have no trouble catching and throwing a Frisbee, and am quite good at it actually. Similarly I have been driving for about 14 years with no major troubles. OTOH some people with one eye do very poorly at these tasks, (I am not sure why there is such a disparity, likewise some people with one good eye consider themselves handicapped, but I have never thought of myself that way and no one notices unless I mention it). I would think solopsist's statement of demonstrated ability is the way to go if you have the capacity.
posted by edgeways at 12:30 AM on January 22, 2005

You may have better luck getting a good answer over at the PPRuNe Forums, where you will find a higer ratio of professional pilots/instructors to snarky laymen than here.
posted by Deepspace at 12:33 AM on January 22, 2005

if you have no depth perception (try it with one eye closed); how would you manage to land a plane?

To be a (commercial) pilot it is essential you can land a plane entirely on instruments. I'm not sure, but I think landing on instruments might be a prerequisite of getting a regular pilot's licence anyway?

Also, I'm guessing there's two forms of depth perception. That which is naturally given to you by having two eyes and a brain which can do the math.. and a somewhat artificial form which is based on other forms of perception, size of objects, the change in sizes, etc.
posted by wackybrit at 12:37 AM on January 22, 2005

So you may want to make sure you would be allowed to fly period.

Surely this is the purpose of the FAA physical, right? If you had any sort of physical condition (with your vision or otherwise) that would make you a risk to yourself or others once you got into the cockpit, they would screen you out in the physical exam. Which our anonymous friend has already passed. There won't be another test later, so I have to assume that if depth perception were really crucial for a pilot's license, it would have been tested for in this physical exam.

This actually isn't very surprising. Stereoscopic depth perception is only really effective at close range -- beyond a few feet, other means of judging distance kick in.

I'm guessing there's two forms of depth perception. That which is naturally given to you by having two eyes and a brain which can do the math.. and a somewhat artificial form which is based on other forms of perception, size of objects, the change in sizes, etc.

You're right, except that there's nothing artificial about the second form. Stereoscopic vision is just one of a number of mechanisms the brain uses to judge distance -- it just happens to be the one that we rely on most heavily, which is why Dr. Wu can't catch a frisbee with one eye closed.

People with one eye just shift the cognitive emphasis to the other depth cues. Like lots of brain stuff, this is a lot easier if you're very young when you make the shift, but the Wiley Post story demonstrates that it can be done at any age.
posted by jjg at 2:31 AM on January 22, 2005

Stereoscopic depth perception is only really effective at close range -- beyond a few feet, other means of judging distance kick in.

I agree. I'm effectively blind in one eye and consequently have no conventional stereoscopic depth perception. With just a little adaptation and practise, it's not as big a disability as one might think. You can legally drive a car, and I have a completely clean driving record, for example. I'm not a pilot, but I don't see any reason not to be able to land a plane. About the only problem I have is catching small balls thrown at speed from a few feet away.
posted by normy at 6:34 AM on January 22, 2005

I have depth perception, but I also have the classic Stick and Rudder by Wolfgang Langewiesche, long considered a classic of flight instruction (and one of the first to talk about angle of attack, it's that old!). He addresses depth perception specifically in one section -- while his intent is to tell pilots with normal vision what not to do, it also ends up explaining how pilots with vision problems can still easily fly.

The short version according to Langewiesche is that what we call "depth perception" just doesn't matter at the distances you're dealing with in an airplane. In the air it's no problem at all; you determine if something is in your flight path by seeing it move relative to the windshield.

Landing's much the same thing. Your stereoscopic vision can't judge altitude -- you use the scale of things to figure out where you are. On approach, the runway looks like a trapezoid, and you use its apparent length vs width (a long or a squat trapezoid) and how it's moving in the windshield to determine whether or not your approach is too high or too low; when you're about to land, you're looking at the horizon or at least the end of the runway to judge your attitude and altitude and when to flare.

I suspect that if you didn't know you didn't have good depth perception you wouldn't have noticed in the air.

(I'm 20 hours and soloed, but on hiatus, incidentally.)
posted by mendel at 8:30 AM on January 22, 2005

I second Mendel. Most of the visual distance judgments you will be making as a pilot will be based on size, foreshortening, angle, and motion. You might learn, for example, how far you should be from the runway on the downwind (parallel to the runway) leg by its angle from the horizon. Or the other things Mendel said. Other traffic in the sky will be distant enough that binocular vision won't tell you anything.

There will be no harm in you taking a flight with an instructor and figuring out whether you really want to fly planes. Ignore these naysayers here, and don't try to get the instrument first---most (all?) of the curricula for instrument training rely on you being able to maneuver the plane in the first place. The instructor won't solo you until you've demonstrated your ability to safely handle the plane around the pattern, so there's no harm to anything but your wallet in trying. I suspect you will be fine, and the FAA has already signed off on your vision.

I'm a new pilot (75 hrs), for what it's worth.

Finally, get Stick and Rudder---it's a terrific book!
posted by tss at 10:32 AM on January 22, 2005