Ask the Color-Blind Dude...

Miscellaneous and Personal Stuff I Must Share
41

I had a colour blind house mate. The only problem we had was playing Trivial Pursuit. ‘I’ll have a green question, please’ You what!! Which ones that again??

42

The rules depend in part on where you live. In many countries any visual defect - including color defects - can bar you from a pilot’s license.

Here in the United States the rule is actually written that as long as you can perceive colors well enough to perform your airman’s duties you can fly. Note, the US regs do not say anything about whether or not your perception matches anyone else’s, only that you can distinguish colors well enough not to mistake one for another (if you really want the actual reg I can quote it for you)

So… upon diagnosis my flight doc sent a letter to the FAA saying I had this little problem but asking for me to take an additional test to get limitations waived (more on those in a moment). The particular test I took involved me standing on a hill several hundred feet away from an air traffic control tower while they flashed colored lights at me. I just had to tell the nice FAA man standing next to me which colors were which. Which I was able to do. So even though some of what the FAA calls “green” I see as blue, it’s a separate and distinct blue from other blues used in aviation lighting, therefore I can understand whatever signals, lights, etc. are used and I was declared fit to fly. Specifically, they gave me a piece of paper called a SODA (Statement of Demonstrated Ability) saying that even though I was colorblind I could still distinguish colors enough to be safe.

What if I hadn’t passed the test? Under US rules I would not have been permitted to fly at night or “where light signals are required”. Technically, that wouldn’t stop me from getting a commercial license and earning my living flying - so long as my flying job did not require flying at night. With a SODA I can fly anything I can afford, whenever I want. There are a number of colorblind pilots doing it for a living out there, a couple are even working for passenger airlines according to rumor.

In actual practice – it can be a little harder for me to spot the airport beacons at night. That’s about the only difference. I tend to spot them a little later than most other pilots. So I work hard on the navigational skills and maintaining situational awareness. No problems spotting the navigation lights on other planes, or obeying light signals from towers on the rare occassion that’s been done when I’m flying. It’s actually easier for me to pick out the light signals at night than in the daytime.

As for someone completely colorblind… the visual defects resulting in monochrome vision usually cause other visual defects. In particular, achromotopsia results in intolerance to daylight and visual acuity that’s so diminished as to leave the person legally blind. These folks can’t drive a car safely, much less fly an airplane. That’s not due to lack of color vision, though, that’s due to other visual defects that occur with their particular condition.

However, if some exceedingly rare thing caused a person to have monochrome vision, yet left them still able to tolerate daylight, their vision correctable to 20/40 or better, and didn’t cause any other neurological defects… then I don’t see anything in the regulations that would ban them from flying in the United States. But in that case no flying at night or via light signals from a control tower.

So… I get a little cranked when I see websites that declare “colorblind people can’t be pilots” because it ain’t true. I have the paperwork to prove it. On the flip side, I would caution any colorblind person considering flight training that there are a few extra hoops for them to jump through.

43

Most traffic lights look white or slightly-greenish white to me, but I can definitely see green. Not sure where this fits in to the latin-definition-soup. :smack:

44

I thought these would be of interest:

http://www.yorku.ca/eye/specsens.htm
http://www.photo.net/photo/edscott/vis00010.htm

These both show the same graph in slightly different variations. The graph is a graph of how the three types of cones(plus the rods in the first link) react to different wavelengths of light. The graph on the second page is about halfway down the page (I prefer its graph - the first link’s graph is “normalized”)

The brain processes color by analyzing and integrating the output of each cone type. In the most common form of color blindness, the green cones would be lacking and the middle curve would disappear. Since the green is almost redundant, most colors can still be distinguished, but near the red end the colors would lack the differentiating factor of the green cones.

45

Sorry I missed your post the last few days, Broomstick! But, thank you for that excellent information!

46

One more thing about the flying -

At certain times of the year, usually spring and fall, I seem to find it easier to spot turf runways than most other pilots. My latest theory is that in some circumstances where everyone else is seeing a green runway on a green background, with everything shades of green, I may be seeing something more like different colors. But it’s a pretty subtle effect.

47

Broomstick, my theory is that your eyes are more sensitive to texture, rather than to color. Not that you can see it better, but you pick up on it better as a clue.

I’ve found that a 15 percent gray hue on my eyeglasses lets me seperate and define things a lot better.

48

But at a great height, E-Sabbath, doesn’t all texture look alike?

And didn’t someone mention that color-blind people are great (in some cases) in picking out those who are camouflaged?

I mean, for a lot of camouflage, it doesn’t work with me. I’ve always wondered how, for the most part, people are fooled by such a thing. What do you think?

49

I’d have to disagree, Skip, the aggregate texture caused by short grass versus the texture of tall grass is easy for me to pick out at altitude. (Ultralights only)

50

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51

I’m not E-Sabbath, but I’ll butt in anyway.

To the untrained eye textures at altitude tend to look alike, and certainly above a certain point they will. But at the altitudes an ultralight flies - or the ones most unpressurized planes fly at - visible textures do exist. At 3000 feet most pilots can distinguish different crops in fields, wet vs. dry fields, bushes vs. trees, deep vs. shallow water, concrete vs. asphalt, and so forth.

I think you’re colorblind, Skip.

In WWII the red-green colorblind were recruited specifically to look for camoflagued troops and equipment. The mottled camo is designed to work on people of normal vision. If your color vision isn’t normal, you are less likely to be fooled. Since my color vision is almost (but not quite) normal camo often (but not always) does work on me - but not always.

Nowadays I think they use thermal imaging to spot folks hiding under mottled tarps. >sigh< Another talent made obsolete by technology.

Folks who are colorblind may pay a little more attention to textures,shapes, and shading that those with normal color vision, which also gives them slightly different spotting skills than the normally sighted. Oliver Sachs addresses some of these questions in Island of the Colorblind.

52

Satisfying Andy Licious: That, my friend, was beautiful! Any time someone wants to shower my thread(s) with happy face art, go right ahead! :slight_smile:

Broomstick and E-Sabbath: I probably should have made it clearer that when it comes to texture at greater heights, I have no more experience than vaguely staring out an airplane’s passenger window. But I’ll be winging out to LA here pretty soon, so I’ll be paying more attention to the texture as we take off and land. (I’m sure I’ll be saying, “Well, duh!”)

As for the camouflage, I didn’t know if the failure was because of me being color-blind or maybe I just wasn’t viewing the camouflaged person(s) in the appropriate setting for the camouflage colors.

It’s good to know that if Klatu and Gort ever land to take our electricity away, I’ll be considered a secret anti-camouflage weapon again.

Yay for job security!

53

Thanks, Skip. Humor aside, I’ve learned a lot of interesting things from this thread.