UA744Flagship
Topic Author
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Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 11:24 am

Hello, I'm in the market for a new pair of sunglasses.

I've heard polarized are not advisable for use in the cockpit, though I know for sure they are better for your eyes in any other environment.

Is it really true? Does polarized = bad?

I have been using polarized sunglasses for the past 1.5 years, with no problems so far in the cockpits of pipers and cessnas. But I don't know if those windscreens are polarized themselves or not.

Thanks.

no wire hangers!
 
SkyGuy11
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 1:06 pm

The theory is that looking through your polarized sunglasses and simultaneously looking through the polarized windshield can cause distortion (I believe it looks like an oil slick), which can in turn hide an aircraft from view. Now, to what extent this occurs and if your planes' windshields are polarized I am not sure. Polarization cuts down on reflections from various surfaces including particles in the air (at certain angles to the sun), reflections from water, and reflections from glass.
.
 
Guest

RE: Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 1:32 pm

I've never found polarized lenses to be of much benefit in aircraft cockpits and, depending on what material the windscreen is made of, they can cause "interesting" and undesirable visual effects. Get yourself the best quality lenses you can find (they don't have to be that expensive either) in a good dark gray tint. The larger the lenses are the better and make sure that they have the UV coating on them. A few years ago there was an excellent article in Aviation Consumer on selecting the proper sunglasses. Every once in a while I see old copies laying around in the magazine piles at the FBOs we frequent. Check around the airport, you might luck out and find the article.
 
flightsimfreak
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 3:48 pm

What polarizing does, is straightens the waves of light by rotating them so they are all flowing the same direction. (this is from a perfunctory chem lecture... So don't get mad if I'm wrong) If you have two polarized objects that are not rotating the light to the same plane, for example, one rotates it 10 degrees left from vertical, and another rotates it 25 degrees left from vertical, then they will interfere with each other and cause the view to darken, distort, get rainbow patterns, and if they are 180 degrees from each other (I believe) they will cancel each other out, and no light can pass through the surface. Therefore, if the windscreen of the aircraft is polarized, and you look at it through polarized sunglasses, it could be distorted.
 
Illini_152
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 3:58 pm

While they're good for fishing, and great when driving, the very property that makes them good for this, can make them bad for flying. Polarized lenses will filter out glare reflected off of a flat object. Like that car in front of you on the highway, or the surface of the water, allowing you to see the fish.

The problem is, this also means that that glint of light off of another airplane that often helps us see them won't reach your eyes. That, and the odd reflections that Jetguy mentioned, and they will blank out some LCD displays all are detractors from cockpit use.

- Mike
Happy contrails - I support B747Skipper and Jetguy
 
UA744Flagship
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Jan 08, 2003 10:13 pm

Thanks everyone! Just goes to show there is no topic too mundane in aviation... except for maybe airbus v. boeing... Big grin
no wire hangers!
 
BlatantEcho
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RE: Aviation Sunglasses - Polarized Or Not?

Thu Jan 09, 2003 4:59 am

FlightSimFreak is pretty close.

Polarization in a lense is a 3-layer laminate. Imagine the mesh on a screen door. Each of the the three layers on the lense coat is layered on perpendicular to the other layer below or on top of it. Light refleted from a curved/distorted surface, such as a ripple in water while fishing, will not pass through the three layers. Only straight light can fit through the slots made from the mesh look polarization layer.

LCD screens and things look distorted from certain angles, and usually from ANY vantage point are hard to read. Don't know if modern airliner windscreens are polarized, though I would doubt it.

Talk to your optometrist about the best ways for YOUR eyes to have strain reduced, and your local qualified optician should be able to fit a fine frame with lots of coverage and good wrap to you with a lense selection perfect for your flying style. We certainly do it all the time for our aviation patients.

George

*side note: do not get photochromatic lenses either (ones that change from light to dark). They will not tint behind glass that has a uv protectant layer on it. (yes, lense companies are working on getting around this)  Smile
They're not handing trophies out today
 
Guest

RE: Aviation Sunglasses - Polarized Or Not?

Thu Jan 09, 2003 6:01 am

Just to throw it out...
The Beech King Airs use a rotating polarizing filter at each cabin window to act as sun shades, they work well. I've been using photochromatic lenses for the past 8 years in the jets that I fly and they work well, except on the "brightest" days and the don't go quite dark enough. That's when I break out the standard sunglasses.

Jetguy
 
mirrodie
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RE: Aviation Sunglasses - Polarized Or Not?

Thu Jan 09, 2003 7:20 am

Forum moderator 2001-2010; He's a pedantic, pontificating, pretentious bastard, a belligerent old fart, a worthless st
 
L-188
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RE: Aviation Sunglasses - Polarized Or Not?

Thu Jan 09, 2003 3:23 pm

Do not wear polarized lenses if you are flying a floatplane.

Those lenses make the surface invisable. I wear them to see fish swiming in the water. But that means it is nearly impossible to see the surface of the water to judge your height above it.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
BlatantEcho
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RE: Aviation Sunglasses - Polarized Or Not?

Fri Jan 10, 2003 1:23 am

Jetguy-

Surprised your biz jets don't have UV blocking windscreens.

If they did, your photochromatics wouldn't work, but looks like you're in luck.

Regards,
George
They're not handing trophies out today
 
avioniker
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RE: Aviation Sunglasses - Polarized Or Not?

Fri Jan 10, 2003 2:55 am

One of the first troubleshooting steps I teach for the 717 or 737NG displays is "Remove your Ray Bans". It's even included in one of the final exams. My company has actually had a couple of gripe calls for dim displays because the person in the seat didn't know about polarization. Anyone coming through the FSBTI or AA courses gets the word up front.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
SSTjumbo
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RE: Aviation Sunglasses - Polarized Or Not?

Fri Jan 10, 2003 8:00 am

I have 20+ hours [ Embarrassment ] training time in a Cessna 152 and am waiting on my solo checkride. I use the same big ol' wrap-arounds in the cockpit as I do in the pickup truck. They're the same style you see many bike riders using, except they're tinted grey, and they work like a charm Big grin.

Cheers
Mike
I don't know, so this is my signature.
 
socal92057
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Sep 07, 2011 7:13 pm

The basic AO Original Pilot has been the U.S. military issue sunglasses since 1958. Cost at this website is $33.99. These are not knock-offs. They are the real deal and I have been wearing them for almost 40 years in the military and out.

www.AOEyewearOnline.com
 
GST
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Sep 07, 2011 9:43 pm

I found out the hard way that my sunglasses were polarised when I had to rotate my head 90 degrees to be able to read the electronic display on the radio console. Polarised lenses can be very bad with electronic displays so unless you are flying an entirely steam gauge cockpit then interesting window effects could be the least of your problems.
 
FredT
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RE: Aviation Sunglasses - Polarized Or Not?

Fri Sep 09, 2011 7:56 pm

Quoting Jetguy (Reply 7):
The Beech King Airs use a rotating polarizing filter at each cabin window to act as sun shades, they work well.

For a while, until they are left standing in the sun a few times with the windows in the 'shade position'. Eventually, one polarization filter is burned off, leaving you with windows which cannot be darkened but which make roads indistinguishable from rivers at times. We've got one aircraft where it's still working, and one where it's all gone. I'd rather be without in both.

Plexi when stressed will polarize light. Net effect is that you can see stress in plexiglass when viewing the plexi through a polarizing filter. Polarized sunglasses are a polarizing filter. Now, do you really want to see the stressed parts of the plexi windshield as opaque?

Then there's the issue of LCD displays, as described above. Tilt your head, and the display goes black. Not good.  

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
ThirtyEcho
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RE: Aviation Sunglasses - Polarized Or Not?

Mon Sep 12, 2011 4:24 am

Here is the main reason I do not use polarized sunglasses: the polarization eliminates the sun "glint" reflected off of another aircraft. I can't tell you the number of times I have been alerted to another airplane, even at a distance, by that unmistakable flash of light.
 
tdscanuck
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RE: Aviation Sunglasses - Polarized Or Not?

Mon Sep 12, 2011 1:57 pm

Quoting UA744Flagship (Thread starter):
Is it really true? Does polarized = bad?

If you have a stretched acrylic windshield (i.e. a big jet), yes they are bad.

Quoting Skyguy11 (Reply 1):
The theory is that looking through your polarized sunglasses and simultaneously looking through the polarized windshield can cause distortion (I believe it looks like an oil slick), which can in turn hide an aircraft from view.

It's true. It makes the windscreen look absolutely terrible. And oil slick is a good description.

Quoting BlatantEcho (Reply 6):
Don't know if modern airliner windscreens are polarized, though I would doubt it.

I don't think they're polarized by design, but lots of large windscreens have layers of stretched acrylic in there, which is naturally polarizing. It causes the windscreen to look terrible through polarized sunglasses.

Tom.
 
AAR90
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RE: Aviation Sunglasses - Polarized Or Not?

Mon Sep 12, 2011 4:19 pm

Recommend using NON-polarized sunglasses. With more cockpit displays going "flat panel," you never know when you might suddenly lose sight of something important because of polarization. i.e. the entire 767 cockpit during an approach in my case.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
Fly2HMO
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RE: Aviation Sunglasses - Polarized Or Not?

Tue Sep 13, 2011 5:17 am

Quoting UA744Flagship (Thread starter):
Is it really true? Does polarized = bad?

Depends on the plane from my experience, and IMO everyone is making it sound worse than it really is (for GA planes at least).

I've used polarized lenses 70% of my flight time with no issues. It seems pretty obvious to me that most LCD avionics manufacturers (Garmin especially) seem to anitcipate the possibility of a pilot using polarized lenses. I use the cheap-o wal-mart clip-ons over my prescription lenses. As long as I don't tilt my head significantly (not enough to touch my shoulder with my ears) I can see the G1000 and GNS430/530 screens just fine. Same with the classic Bendix nav/coms in early C172S models. Of course your mileage may vary and I've yet to fly heavy metal but from my experience polarized lenses should not be a major issue.
 
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alevik
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Sep 21, 2011 6:22 pm

I'm not a pilot, but I do have polarized sun glasses. A few months ago a picked up a brand new BMW with a heads up display.

If I'm wearing my polarized sunglasses, the data on the heads up display is invisible - not dim but invisible, unless I tilt my head to a 45 degree angle.

I have to imagine similar circumstances could occur on aircraft instrument displays.
Improvise, adapt, overcome.
 
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bikerthai
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Sep 21, 2011 6:37 pm

Quoting FredT (Reply 15):
Plexi when stressed will polarize light

Brings back memories . . . anyone remember that stress tensor experiment in engineering lab when you had to count the stress pattern around a hole of a plastic plate using polarized filters?

bikerthai
Intelligent seeks knowledge. Enlightened seeks wisdom.
 
777ord
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RE: Aviation Sunglasses - Polarized Or Not?

Wed Sep 21, 2011 6:38 pm

I love my polarized Ray bans. However, the "oil slick" mentioned was originally an eye sore, but has actually come to be helpful. Only in that that glare reduced overweighs the benefit of that oil slick appearance.

HOWEVER, If you use an iPad AND polarized lenses.... You better turn the ipad 90 degree's to the left/right or you won't see a THING!

Now, for those of you who fly with iPads, do you know of any windshield/glareshield mounts for the iPad that can be tilted L/R 90 degree's to compensate for this issue??

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