To Polarise or not to Polarise, gentlemen that is the question

[FlyingKiwi_73]

Hi chaps,

Getting some prescription sunnies soon, possibly even some 'drive wear' glasses.
Just curious to hear what you think about polarisation, especially with LCD screens (such as GPS) in the cockpit.

Anybody have any preferences when it comes to your Top Gun glasses?

Flame away......

[maxred]

Cant see

I have tried, not quite them all, but a fair few. Expensive ones, cheap ones, in between ones, and I still struggle to adequately read instruments, inside the cockpit.

I will be interested in responses to this. I generally end up taking the sunglasses off for take off/landing,possibly rendering the whole affair useless.

[caber0]

Polarising sunglasses are likely to cause colour patterns from stresses in the screen of most planes so should be avoided. Ifyou normally wear glasses then get prescription sunglasses and get them to tint them a bit lighter than normal. If not then proper rayban aviators are good, there was a good reason for graduated tints so they are clear at the bottom, so you can see instruments inside the cockpit not fashionable these days but functional.

Caber

[mutt]

Polarized glasses are a big no no in glass aircraft, they block out a lot of the screens. Do you some research in Pprune as this is an old question and you will find a link to an excellent FAA article explaining why Polarized glasses don't work.

Cheers

Mutt

[Phenom100]

I will second Mutts quote, they are a big NO NO in glass cockpit.

[ei-flyer]

FlyingKiwi_73,

Whilst the above remarks about polarised sunglasses are correct with regards to LCD screens, I think this thread so far smells a little negative!

You only gave GPS as an example - in that case, GO FOR POLARISED! If you are flying an aircraft equipped with analogue instruments, but with a portable GPS, you won't have a problem. Most portable units in GA are not any more difficult to see with polarised glasses than they are with standard sets. This is because the majority of them are not of a particularly high 'pixelage', and a bit ancient in technology. If you DO have a more modern LCD screen GPS, do not fear - polarisation only affects viewability in certain planes of vision. For example, if you look at the screen and see is as completely black, for example, just swivel the GPS unit a little until you can see it clearly.

I will echo above comments with regards to glass cockpits - yes, it is a BIG nono and would be especially dangerous if you were flying IMC relying on all the data from those screens.

There are a multitude of benefits, least of which are things like being able to look pretty much anywhere in the sky without having to squint at all, being able to see twice as far in haze as a 'non-polarised pilot' etc. I don't know how to describe it exactly, only that I honestly feel I would not enjoy my private flying half as much if I turned up at the airfield having forgotten my polarised prescriptions!

Safe flying

[172driver]

In a word - NO

Unless, of course, you really dig those great, fancy colourful reflections in the perspex. Not to mention glass cockpits....

Go for standard prescription glasses, ideally one with the bottom half lighter than the top.

[FlyingKiwi_73]

Cheers all, bit interested to understand the issue with windscreen's since they are perspex etc and not laminated or toughened glass surely there should be no problem.

I'm thinking of opting for the driver tints so i can go from light to dark quickly and see both 'outside' and do my instrument scan. i was just a bit concerned when i purchase said GPS i may not be able to see it well.

at the moment I'm Strictly VFR only, if the wife lets me i'd love to do my IR

Not likely to be buying a cirrus in the future so fully glass cockpits aren't of real concern for me

[wsmempson]

Polarising sunglasses have two very interesting effects when used in my aircraft;

1. The display on my KX155 nav com appears to be dead, until I tilt my head to an angle of 70 degrees, whereupon it comes to life again.

2. The windscreen suddenly looks as if it is criss-crossed with millions of spidery, silver crazed lines - which very much spoil the view.

My recomendation would be not to use polarising sunglasses! :-)

[BackPacker]

I can testify from experience that even the LCD displays on stock standard 15-year old radios become invisible to read with polarized glasses.

As the aircraft I usually fly don't have glass cockpits or other highly critical displays in them which require non-polarized sunglasses, I'm keeping them for now and just do the head-tilt whenever I need to switch frequencies. But otherwise they would be the first to be replaced. And next time I'm going for non-polarized.

bit interested to understand the issue with windscreen's since they are perspex etc

I *think* (but am not sure) that polarization can appear in any transparent material that's being stretched in one direction. Probably because that stretching causes the long carbo-hydrate molecules to align themselves with the direction of the stretch. If you have a bubble canopy then that's usually formed by heating a flat piece of perspex and then using a vacuum to suck it into a mold. This leads to local stretching and thus polarization. So it might be a problem on any windscreen that's being bent in two dimensions, but not in anything that's flat or only bent in one dimension. (Depending on the fabrication process in any case.)

(Then again, I'm not a chemist so I may be entirely wrong.)

[MIKECR]

Definite no no with polarised and glass screens.

Wont go far wrong with a pair of Serengetis!

[FlyingKiwi_73]

I have to go the prescription rout i'm afraid no serengeti's for me.

I have been wary about wearing contacts (i do this when i'm diving, not an avaiton compatible hobby i know), about 7 years ago on final in a K-21 i 'blinked' out a contact which made judging the hold of and flare interesting!

Since most of the stuff i fly has folded windows i'm guessing it should not be too bad, love to fly a bubble canopy!!

[FlyingKiwi_73]

It makes a good point about sun flashes of wings etc,.. i had a horrible job spotting a C180 in a valley north of Omaka, the C180 did a 90 deg turn and i caught the wing flash. we were in constant RT contact but just could not see each other,.. once i visually picked him up we nominated our valley sides and proceeded past each other.

Would polarisation really stop this?

[RatherBeFlying]

Compared to the various high tech sunglass providers, optometrists seem limited in what they can do with prescription lenses.

On my prescription lenses, I use a 30% transmission brown tint as opposed to a neutral grey as it filters out some of the blue.

That allows me to see well when under a cloud and be comfortable in direct sunlight.

Polarising can also block sun glints from other aircraft -- that can be a valuable alert to the presence of another aircraft.

[ei-flyer]

Definitely a non no. You simply can't see the display.

Well I've never had the problem with portable GPS units and polarised glasses...

wsmempson says -

The windscreen suddenly looks as if it is criss-crossed with millions of spidery, silver crazed lines - which very much spoil the view.

Incorrect, not in 99% of light aeroplanes. In our jets with heated and whatnot windshields, yes, but plain old Cessna/Piper perspex is no problem at all.

I think some people are being a little OTT about things which really are no issue at all when in the air. I have a couple of thousand hours in Cessnas - the polarised sunglasses are 400 hours TT now, and so far, I've never witnessed any of the above mentioned effects. Not saying they don't happen though...

[FlyingKiwi_73]

ordered glasses.... tinted,...polarised :-)

Watch the NZ news, "idiot pilot lands on motorway"

[742-xx]

IF polarized are such a no no then why do Transair sell them ?

SERENGETI GRANADA SUNGLASSES POLARIZED

I use Oakley polarized and, up to now no probs...

[mad_jock]

Usually I am a 20 quid a pair man from the super market because I seem to be able to loose a 100 quid pair as quickly as a 20 quid pair.

But as the last pair managed 12 months without breakage going missing after a post on here I gave these a go.

Mile High - ONLINE STORE - Rapid Eyewear - Pilot & Aviator Sunglasses, High Quality, Versatile Aviation Sunglasses

Pretty impressed actually and quite like the choice of lenses. The yellow ones are cracking to drive into the night with gives you another hour of percevied day light. Frames don't leak sound into my headset either. For skiing they are cracking as well.

[Deeply Concerned]

If buying prescription lenses (or even not), remember there's a huge difference between a glass or plastic lens to which a tint has been applied to the surface, or a lens manufactured from material containing the tint. Ray Bans (and other quality lenses) made in this way filter infra-red and U/V light, whereas a piece of tinted plastic looks dark, but actually allows I/R and U/V through. This is much less effective and in the long term damaging to ocular health.

Also do not confuse the price with quality. There are many expensive designer sunglasses that use quite cheap lens material. If you fly a lot, push the boat out and go for something like Zeiss Umbral lenses made to prescription. I believe Ray Ban is also available in prescription.

[24Carrot]

Another well-known problem is reflection off water.

If you are sipping beers by the poolside or beach, polarised lenses work fine.

If you are trying to spot lakes from 3,000' through a sunny haze, they don't.