Sunglasses

i can't bring myself to wear a pair of "aviator" sunglasses!..i have this fear that as soon as i give in that i'll magically grow a porn 'stache in my sleep and wake up wearing a ssswwweeeeeettttttt leather pilot jacket signed by Goose and Maverick. i don't want to be that guy, please 6lbs 8oz baby jebus don't let me be that guy
 
unclenobby said:
I have a pair of coloreyes. Very light and fit nicely with the headset. They had them at my FBO, took them for a test flight and really liked them. Great clarity. Seems like my FBO is considerably cheaper than the coloreyes website too..!! :)
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EFA?
 
TFaudree_ERAU said:
but that could be because I've sat on them 3 times and had to have them fixed at Lens Crafters.
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Hey if you send them back to Serengeti with a letter they will replace them with what ever size or style you want for a reasonable fee. I have broken mine twice. One time they charged me and the other time they covered it under warranty.

http://www.serengeti-eyewear.com/

http://www.serengeti-eyewear.com/support/us_repair.cfm

These are my favorite. You can wear them from dusk to dawn and in bad weather. They really clear things up when in fog, haze, and mist.

6826_serengeti_mdaviator.jpg
 
I know this was brought up awhile back, but:

As per the Serengeti's, are you guys getting polarized or non? I've heard that the polarization that already exists on windows and screens in the cockpit can do weird things when you combine it with polarized sunglasses.
 
Doug Taylor said:
You know, the polarized lenses do funny stuff to some heated windshields, and depending on the polarity of the autopilot LED's, can absolutely blank the inidications (bad problem on MD-88/90's), but I liked the glasses so I made do.

I like the polarized lenses, but if you add polarized lenses with being new on a aircraft with LED-displays, you're asking for trouble unless you learn "how" to look at the displays. If you do the "RCA Dog" head tilt, it usually helps.
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gredenko said:
I know this was brought up awhile back, but:

As per the Serengeti's, are you guys getting polarized or non? I've heard that the polarization that already exists on windows and screens in the cockpit can do weird things when you combine it with polarized sunglasses.
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IMHO, Polarized lenses have no place in a cockpit with internally heated windshields or LCD screens. You are compromising safety by having to tilt your head back and forth to simply read a screen or see out the front. Better to not have shades at all.
 
From the FAA Safety pamphlet "Sunglasses for Pilots: Beyond the Image"
http://www.faa.gov/pilots/safety/pilotsafetybrochures/media/sunglasses.pdf

POLARIZATION​
​
​
. ​
Polarized lenses are not recommended
for use in the aviation environment. While useful for blocking
reflected light from horizontal surfaces such as water or
snow, polarization can reduce or eliminate the visibility of
instruments that incorporate anti-glare filters. Polarized lenses
may also interfere with visibility through an aircraft windscreen
by enhancing striations in laminated materials and mask the
sparkle of light that reflects off shiny surfaces such as another
aircraft’s wing or windscreen, which can reduce the time a pilot
has to react in a “see-and-avoid” traffic situation.​

 
MDPilot said:
POLARIZATION.
Polarized lenses are not recommended (not "illegal, unsafe, or against the FARS")
for use in the aviation environment. While useful for blocking
reflected light from horizontal surfaces such as water or
snow, polarization can (not "does") reduce or eliminate the visibility of
instruments that incorporate anti-glare filters. Polarized lenses
may (not "most definately do") also interfere with visibility through an aircraft windscreen
by enhancing striations in laminated materials and mask the
sparkle of light that reflects off shiny surfaces such as another
aircraft’s wing or windscreen, which can (not "will") reduce the time a pilot
has to react in a “see-and-avoid” traffic situation.​
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It's not that they've spent ton's of out tax dollars to determine if polarized lenses are good or not. It's just a simple recommendation because "of their possible interaction with displays or other materials in the cockpit environment." If you are fully aware of that issue and have compensated... or do not have any displays that are an issue... then...

I respect what the FAA has to say... (most times ;)) but like Doug and I both suggested above... if your try them out first in your aircraft before flying and there are no major issues... then they may very well be worth it to you.

Here's more info from the way back machine: ;)

Captain_Bob said:
I'd steer clear of polarized lenses for flying for 3 reasons.

1. They cut down on glare, which is actually what makes them so great, but when flying, glare off of another airplane helps you to see it. So polarized lenses make it harder to spot traffic.

2. If you plan to fly anything with any type of LCD display, particularly a glass cockpit, you won't be able to see it through your sunglasses. It dosn't even have to be anything all that special, it could just be a simple GPS or even a nav/com. I used to have a pair of polarized glasses and I couldn't even see my digital watch through them unless I looked at it at just the right angle. I also couldn't see the display on gas pumps, though this was before the gas prices were so high so I didn't usually have to watch it very closely.

3. They are expensive. They are great for driving, but if you are looking for something for flying don't spend the money. They may give you more problems than bennefits.

Apart from polarization, you should get something that blocks all colors equally. That way no colors get washed out. Same reason its recommended you don't use a red flashlight for looking at your charts at night.
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Couple of things here... I use polarized lenses (Maui's & Native's) and I fly glass cockpits...

A friendly Point/Counterpoint to the above numbered items regarding polarization:

1. They cut down on glare... which actually helps you see traffic. By cutting down on the glare off the clouds, the water from the lakes, the sun reflecting off the dash, etc... I'll say this as well... when you have another jet at 20 miles on TCAS at 12 o'clock with up to a 1000 kt closure rate, it's typically not a glare that catches your eyes... it's a good scan of the area indicated on TCAS or reported to you by ATC. There have been many time both me and my capt. have been like: "you see it?", "Not yet", "Is that it?", "Where?", "Over there, 11:00", "Don't see what your seeing", "Oh Crap, there it is 12:00!"... as it flys right under us. "Uh Center... Traffic in sight... no factor." ;) A good scan will overcome any lens.

2. The LCD thing comes into play in some situations... it depends on whether the lenses you have are polarized horizontally or vertically. Most are horizontal and there is no issue with seeing LCD displays unless you physically tilt your head 90 degrees to look at a display. The only LCD display's in the ERJ are the com-panels and clocks... no issues there at all. The "Glass" instruments are no problem... all they really are, are CRT's. Not LCD panels. So there really is no issue... it's like watching TV with your sunglasses on. That being said I do know that the smaller GA planes have garmin-esque displays like the 430/530/1000 etc... and those are LCD but I have found the same results... unless you are looking at them with your head cocked 90 degrees.. it's a non-issue.

3. They are not expensive... you can go to wally-world, k-mart, etc... and get a cheap pair of $9.95 - $20.00. Just look for the "polarized" sticker on the lens. Not the best qaulity but no different than the other sunglasses on the same display that are not polarized. Of course in both types you can go from that amount up to well over $300/pr.

Your last statement about colors... it is true. Different color lenses washout different colors. Here's a basic breakdown:

Grey/Green lenses: Most color accurate lenses with the least contrast. Does not distort colors to the user so great for general use and VFR. Usually darker than other lenses and thus not good during early evening/morning twilight hours.

Brown/amber lenses: Distort colors slightly, while providing good contrast (ability to see between light and dark objects). Can be used later and earlier in the day without causing the too much darkness inside the plane. Best overall lens when it comes to usefullness.

Rose Lens: Most color distortion. But provides the best contrast of the other lenses. They are wonderful for early and late in the day, but may not be enough for the middle/brightest part of the day.

I actually use a Gray lens during the brightest part of the day and switch to Rose during the early/late phases of the day, I also use my Rose lenses during IMC because of the contrast... you'd be surprised how you can actually see between clouds and differentiate layers with a rose lens, as well as spot traffic sooner as well.
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Bob

​
 
Just to let you know the credentials of the guys who wrote that safety pamphlet:

Mr. Montgomery is a Vision Research Specialist at the FAA’s Civil Aerospace Medical Institute in Oklahoma City, OK. Dr. Nakagawara is a Research Optometrist at Civil Aerospace Medical Institute, and he is also a charter member of the American Optometric Association’s Aviation Vision Committee.


Also, from "Soaring Safety"
SUNGLASSES AND POLAROID PROBLEMS


"It was bright but hazy with 40 miles plus visibility. Radar advised me of an aircraft at the same altitude which was slowly overtaking on my left side. Soon it was reported at 9 o'clock and three miles. The sun was behind me. It was near noon. I couldn't see the traffic until I slipped off my polaroid clip-ons and suddenly the image of the other aircraft snapped sharply into view with considerable contrast against the hazy background. When I put the polaroids back on again, it was a moment or two before I could find it again since there was almost no contrast between the aircraft and sky."
Our Aviation Medicine experts explain this phenomenon:
Sunglasses reduce solar glare from direct, reflected and scattered sunlight. Glare may cause both discomfort and reduced visual acuity. The ideal sunglasses for aviation are neutral grey in colour to avoid affecting colour discrimination, and have a luminous transmittance of between 10 and 15%, that is, they will filter 85 to 90% of the glare effect. Polaroid lenses are constructed by placing a matrix of minute dichroic (double refracting) crystals between two pieces of glass. The matrix is oriented so that the lens acts as one large crystal which polarizes light in one direction, usually in a horizontal plane. They are therefore very effective in reducing glare. However, since aircraft windscreens are usually made of laminated glass, the combination of a laminated windscreen and a polaroid lens may produce polarization of light in two planes, thus effectively blocking vision

and,
LIGHT POLARIZATION AND SUNGLASSES FOR PILOTS


Anecdote from the: "Sunglasses and polaroid problems":
"It was bright but hazy with 40 miles plus visibility. Radar advised me of an aircraft at the same altitude which was slowly overtaking on my left side. Soon it was reported at 9 o'clock and three miles. The sun was behind me. It was near noon. I couldn't see the traffic until I slipped off my polaroid clip-ons and suddenly the image of the other aircraft snapped sharply into view with considerable contrast against the hazy background."
Comment by Lt. David M. Kennedy (USN), ( in APPROACH Magazine, September 1984) :
"Polarized lenses are specifically not authorized for inflight wear due to the possibility of blind spots caused by the cumulative polarizing of canopy/windscreen, visor and sunglass lenses."
POLAROID SUNGLASSES
Polaroids are made of materials typically based on polyvinyl alcohol with iodine or some dyes incorporated into it. These materials exhibit linear dichroism with the direction of the absorbed polarization being set into polaroid sheet by an anisotropic stretching process. In that process the long polyvinyl alcohol molecules are oriented along the stretch direction, and thus the incorporated iodine or dyes become anisotropically active. Good polarizers fabricated this way transmit more than 80% of one polarization while essentially completely eliminating the other. Typical field of view of human eyes is +-35 degrees from the normal to the glasses. For all practical purposes one can consider light viewed through polaroid sunglasses to be incident perpendicularly to lens surface, and dispense with extra complications in discussion.
Most, if not all polaroid sunglasses sold in the stores are set to transmit light polarized vertically (in the frame of a standing person wearing the glasses). This suppresses glare caused by sunlight reflecting off a rear window of a car which is being followed, to darkening of sky toward the zenith when the sun is behind an observer wearing the polarizing sunglasses, and reduces haze with the sun overhead.
POLARIZATION VIA SCATTERING
Direct sunlight is unpolarized. As it traverses the atmosphere it is scattered within it by air molecules, small particles, molecules or tiny droplets of water and so on. For the most part this scattering is strongly, but smoothly, dependent on the wavelength of light. Blue light scatters roughly five times stronger than the red; thus the blue sky. Small particles (smaller than two tenth of a micron in diameter) scatter unpolarized sunlight more or less equally in all directions. However, as the scattering angle approaches 90 degrees the light becomes strongly polarized in the direction perpendicular to the scattering plane. This is strictly true for a "single scattering event". In the atmosphere, light often undergoes multiple scattering events before reaching the observer, thus the polarization due to this effect is not perfect.
Looking through polarized sunglasses perpendicularly to sun rays, an observer with sun behind him will find a band of darker sky. This effect is often used by photographers to increase the contrast of clouds against the sky. This also benefits a glider pilot who is looking for a small whisp of a cloud against the sky's background. When the sun is near to horizon the polarized band is overhead. At noon, with the sun nearing zenith, the polarized band moves towards the horizon. As an observer samples a greater distance through the atmosphere, multiple scattering effects become more important and the degree of polarization is lowered for a band close to the horizon.
The same effects are observed with scattering due to haze. As long as the haze is thin, the scattered light can be eliminated by polarized sunglasses (mostly single scattering events). However, as the haze thickens, multiple scattering destroys the polarization of light coming from further away. Polarized sunglasses now help only with the light scattered close to the observer. As the haze thickens even more, the light from the sun becomes diffuse enough to render polarized sunglasses completely ineffective.
So what is the explanation of the observation in the above anecdote?
I'm going somewhat on a limb but: The sun is overhead (near noon) somewhat to the back, haze is weak (more than 40 miles visibility). The observer is looking for an aircraft to his side, reasonably close to him and near horizon. Aircraft in this configuration does not reflect a lot of light so it is going to be basically a small, dark object against the background. But what is the background? With polaroids on, the observer eliminated light scattered by the haze and suppressed somewhat the intensity of the sky. So he is looking for a basically dark object against darkish background within a predominantly bright scene. I believe that this is one of the worst cases possible for noticing an object. The moment he takes off his polaroids the background lights up increasing the contrast significantly.
But what if the aircraft one were looking for presented itself as a bright object, (e.g. had its lights on, was in a turning bank so that it reflected more light towards the observer). My guess is that the polaroid sunglasses could help in such a case.
POLARIZATION VIA REFLECTION AND TRANSMISSION
About 4% of light incident perpendicularly at a glass surface is reflected on each glass-air interface. As the angle of incidence (half the angle between the incident and reflecting rays) increases, the reflectivity of light polarized perpendicularly to the plane of incidence (plane containing incident and reflecting rays) (s-polarization) increases. However the reflectivity of the light polarized in the plane of incidence (p-polarization) initially slowly decreases, and at a specific angle (Brewster angle) which for glass is about 56 degrees, it reaches zero.
For larger incidence angles, reflectivity of the p-polarized component rises rapidly but is always smaller than that of the s-polarized component until, at glancing incidence (incidence angle approaching 90 degrees) light is completely reflected. At Brewster angle the reflected (not transmitted) light is completely polarized. The reflectivity of the s-polarized component at Brewster angle is about 15% per surface (thus about 70% of this polarization of light is transmitted through a sheet of glass compared to 100% of the other). Metallic surfaces strongly reflect both polarizations.
It is now easy to understand why polarizing sunglasses help eliminate glare from a rear window when one follows a car. With the sun overhead, light reflected from glass surfaces of a car ahead is largely polarized in the plane horizontal to the observer, and that is the polarization that the polaroids absorb. Light reflected off of smooth paint is also to some extent polarized and glare from painted parts can be also suppressed. Note that a slanted windshield of the observer's car also acts as a polarizer (though a very poor one) which is oriented in the same direction as the polarizers of the sunglasses.
What are the implications of that for pilots? I am not sure. In general there appears to be concern about "blind spots" created by cumulative polarizing effects of windows, visors and sunglasses (the windshield effect described above). I do not think this is of any concern for any normal viewing situation. The polarizing effects of the intervening surfaces parallel those of the polaroids. I can imagine however some abnormal viewing conditions in which a "blind spot" might be created, e.g. a pilot tilts his head significantly to look backwards. "Blind spot" in such a case would mean almost total darkness, not loss of contrast. This problem would be exacerbated by a double paned window with an air gap inbetween. Window laminations do not contribute to polarization of light as the bonding materials are usually optically well matched to the glass they join. In my opinion, the "blind spot" effect may be of some concern to fighter pilots in combat, but I doubt very much that they are of any importance to an average pilot; even to a glider pilot who twists his head in a gaggle.
I would be more concerned with a different effect. As mentioned above reflection off paint can be polarized. More often than not I notice other gliders as they flash their wings in a distant turn. With the sun overhead this flash might be lost should I be wearing polaroids.
MY PERSONAL CONCLUSIONS ABOUT USING POLARIZING SUNGLASSES IN FLIGHT Well, I do not think I want to use them. The variation in their effects is just too great. They definitely help in some situations (e.g. increase contrast of light objects against the sky, help see deeper into haze), but then there are also situations that they might be detrimental (see the anecdote above). In my opinion a pilot is better served by using sunglasses which eliminate the deep blue and thus achieve most of the positive effects of the polaroids by eliminating the radiation that is easiest to scatter, and at the same time help somewhat the visual acuity by limiting chromatic aberration effects (light of different colors comes to focus at different distances from a lens) in the eyes. The UV protection they may offer would be another, and maybe the most important benefit


But, since none of this is regulatory, you do what you think is best.
 
Serengeti. Period. Don't buy the big aviator style because you'll look like a freshman at ERAU. (I can say that because I had a pair of HUGE ray-bans when I was a freshman at ERAU).

I have a pair that I think are the Serengeti "Coupe" style (http://www.serengeti-eyewear.com/products/serengeti_classics/serengeti_coupe.cfm)
I bought them from Sam's club for about $80. They stay in my flightbag and I only use them for flying. Period. Haze, low-light, bright light, it doesn't matter. They work great. I did leave them in the airplane 1 time and BAMM, gone! Now I'm more careful although I keep a biz card in the case...just in case.

The rest of the time I wear Polarized Ray-Bans. Love them but hate them in the airplane. Occasionally, I fly with a hapless Captain who forgets his sunglasses so I lend him my Serengeti and I wear the Ray-Bans. The "blackout effect" is so irritating!

My 2 pennies. Go with what you like.
 
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