Sunglasses to wear up there
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halas I have searched and searched for Serengeti Drivers yet never even come across Serengeti anywhere. What is it with this brand? Have they gone out of business? I have almost given up with them! I will not buy glasses on line. They need to fit well, feel good and for flying they must work well for you. IMHO
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hello guys and gals! I had a fright once when I was doing my normal scan in cruise! It seemed as if my VSI on my fokker 50 was missing! I looked across the captains and his was still there. I had few head turns and I finally sussed out that it was my polarised ray burns that brought the eerie feeling! I am now actively looking for normal glass. Currently I get by with unpolarised ray burns
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Not to dampen the enthusiasm of newbies here, before you post such a question, have you ever thought to try the least used button on the site, the search function? You'll be amazed that you actually get results!
This subject has come up almost every year since PPrune began.
btw, and fwiw, after flying for almost 40 years and almost 30,000 hrs airborne and never having worn sunglasses, my eyesight is about as good as can be expected in a 60 yr old. I began to wear corrective lenses for reading about 6 years ago. I can assure you the wrinkles were there when I was at school!
This subject has come up almost every year since PPrune began.
btw, and fwiw, after flying for almost 40 years and almost 30,000 hrs airborne and never having worn sunglasses, my eyesight is about as good as can be expected in a 60 yr old. I began to wear corrective lenses for reading about 6 years ago. I can assure you the wrinkles were there when I was at school!
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Sunnies again! This has been on a few times over the board in various forums, here is a comment I have posted before - although sometimes it has been copied and pasted by others. 
There are several reasons to wear sunglasses. It is generally accepted that glare is harmful to the eye and that protection from glare is therefore therapeutic, even though studies show that only 22% of the population reacts adversely to glare. For these people the pupils are nearly pinpoints under such exposure. Diminished retinal luminescence cause measurable visual decrements and sunglasses will improve this visual acuity problem by counteracting the amount of available light. Conversely another 11% are at the opposite end of the sensitivity spectrum, these people actually have improved acuity under high glare conditions and seem to have no need for sunglasses.
It is not necessary to wear lenses inside the aircraft to protect a pilot from the injurious part of the UV spectrum, because canopy or cockpit windows will also block UV-B. (Acrylics, however, will not block UV effects and Ultra light or open-cockpit flyers will need sunnies.) UV-C is absorbed by the atmospheric ozone and is not supposed to reach the earth. Infrared rays (as in a heated cockpit) are not known to be a eye hazard.
Sunglasses are therefore essential for most pilots in order to cope with glare. The most important consideration for sunglasses is that they reduce glare without affecting vision. Lenses should not be too dark and the standards given for pilots is that they transmit at least 15 per cent of incident light. The tint must be "Neutral density" (ND) which means that it doesn't affect colour perception. The recommended tint for aviation sunglasses is therefore ND15. (This is the US military specification standard for aviators sunglasses and tinted visors, and may have its scientific origins in a 'best guess scenario' more than fifty years ago.) Only sunglasses that conform to the Australian standards should be worn . Those marked "specific purpose sunglasses" are recommended.
Pilots who wear prescription sunglasses may either wear clip-on lenses or they can get their prescription sunglasses made with ND15 lenses. Clip-ons have the advantage of being easy to remove when there is a quick change from light to dark conditions.
If you chose to have your prescription lens made with a tint then it is essential to have another pair of untinted lenses for night and low glare flying. Pilots who wear look-overs are advised to use bifocals instead and then wear clip-ons.
There are two main materials, crown glass and a plastic known as CR39. A very tough poly carbonate lens material is also available. All three lens materials are acceptable. CR39 and polycarbonate have these advantages :
* highly impact resistant;
* light weight; and
* low thermal conductivity and thus less liable to fogging.
CR39 is more vulnerable to surface damage than glass and CR39 lenses must be carefully protected from scratching. CR39 can be obtained with an abrasion-resistant coating to reduce its susceptibility to surface damage.
Polaroid lenses should be left in your boat. (Everybody has one right ) Their chief attribute is that quality Polaroid lenses will completely eliminate glare coming from a flat surface that is of an angle of approximately 53%. A pilot wearing Polaroid lenses sees the world as constantly changing according to his (or her) angle of bank, as the angle of the glare is altered. Liquid crystal displays work by electrically controlling filtered polarised light, so any LCD can appear blank with polarised lenses on (depending on the orientation of the lens), and looking through a polarised window could result in no view at all!
Lens colors are seen in different ways:
* Green or grey are said to give the least color distortion, and are available in combination.
* Yellow has the capability of filtering reflected short-wave blue which is found in air contaminants such as fog, haze, smoke or smog. In certain conditions therefore yellow "blue blockers" can improve visual acuity, but not because they protect from glare. Yellow lenses that cut out more than 30% of ambient light can affect color perception and military pilots complain that depth perception is altered.
* Brown, if it is not too dark, will enhance contrast as well as doing a modicum of blue-blocking.
* Rose also increases contrast and blue-blocking offering a niche in car use.
In summary, aviators' sunglasses should:
* be glass or polycarbonate;
* transmit not less than 25% of available light;
* not distort colors, distances or shapes;
* nullify the blurring effect of short-wave reflected blue;
* have their adverse effect on visual acuity well understood; and
* not be worn under conditions of diminished light.
As an aside, I bought a pair of glass Serengettis with a brown tint for nearly $AUD300. I didn't like the weight of the glass lens at all, and the brown tint, while it was good for glare, made the green information on EFIS a little hard to see when I transistioned to EFIS. In addition the inside of the lens was highly relfective, so as I was sitting in shadow (in the cockpit) looking out at a bright field (like a cloud deck from above) they gave me a perfect image of my eyes looking back at me (reflected from the inside of the lens). That was difficult to ignore. I now fly with a pair of $AUD15 plastic sunnies I bought from a Chemist and I am much happier with them.
In Australia pilots may claim one pair of sunnies per year at tax time.
sources:
-CAA (Australia) Aviation Safety Digest (ASD) 150 (1991)
-ASD 136 (Autumn 1998)
-ASD 133
-CASA's Flight Safety Australia (Sept. 1997)
Copies of all of these articles are available for free if you contact (Australia'a CASA or BASI)
There are several reasons to wear sunglasses. It is generally accepted that glare is harmful to the eye and that protection from glare is therefore therapeutic, even though studies show that only 22% of the population reacts adversely to glare. For these people the pupils are nearly pinpoints under such exposure. Diminished retinal luminescence cause measurable visual decrements and sunglasses will improve this visual acuity problem by counteracting the amount of available light. Conversely another 11% are at the opposite end of the sensitivity spectrum, these people actually have improved acuity under high glare conditions and seem to have no need for sunglasses.
It is not necessary to wear lenses inside the aircraft to protect a pilot from the injurious part of the UV spectrum, because canopy or cockpit windows will also block UV-B. (Acrylics, however, will not block UV effects and Ultra light or open-cockpit flyers will need sunnies.) UV-C is absorbed by the atmospheric ozone and is not supposed to reach the earth. Infrared rays (as in a heated cockpit) are not known to be a eye hazard.
Sunglasses are therefore essential for most pilots in order to cope with glare. The most important consideration for sunglasses is that they reduce glare without affecting vision. Lenses should not be too dark and the standards given for pilots is that they transmit at least 15 per cent of incident light. The tint must be "Neutral density" (ND) which means that it doesn't affect colour perception. The recommended tint for aviation sunglasses is therefore ND15. (This is the US military specification standard for aviators sunglasses and tinted visors, and may have its scientific origins in a 'best guess scenario' more than fifty years ago.) Only sunglasses that conform to the Australian standards should be worn . Those marked "specific purpose sunglasses" are recommended.
Pilots who wear prescription sunglasses may either wear clip-on lenses or they can get their prescription sunglasses made with ND15 lenses. Clip-ons have the advantage of being easy to remove when there is a quick change from light to dark conditions.
If you chose to have your prescription lens made with a tint then it is essential to have another pair of untinted lenses for night and low glare flying. Pilots who wear look-overs are advised to use bifocals instead and then wear clip-ons.
There are two main materials, crown glass and a plastic known as CR39. A very tough poly carbonate lens material is also available. All three lens materials are acceptable. CR39 and polycarbonate have these advantages :
* highly impact resistant;
* light weight; and
* low thermal conductivity and thus less liable to fogging.
CR39 is more vulnerable to surface damage than glass and CR39 lenses must be carefully protected from scratching. CR39 can be obtained with an abrasion-resistant coating to reduce its susceptibility to surface damage.
Polaroid lenses should be left in your boat. (Everybody has one right ) Their chief attribute is that quality Polaroid lenses will completely eliminate glare coming from a flat surface that is of an angle of approximately 53%. A pilot wearing Polaroid lenses sees the world as constantly changing according to his (or her) angle of bank, as the angle of the glare is altered. Liquid crystal displays work by electrically controlling filtered polarised light, so any LCD can appear blank with polarised lenses on (depending on the orientation of the lens), and looking through a polarised window could result in no view at all!
Lens colors are seen in different ways:
* Green or grey are said to give the least color distortion, and are available in combination.
* Yellow has the capability of filtering reflected short-wave blue which is found in air contaminants such as fog, haze, smoke or smog. In certain conditions therefore yellow "blue blockers" can improve visual acuity, but not because they protect from glare. Yellow lenses that cut out more than 30% of ambient light can affect color perception and military pilots complain that depth perception is altered.
* Brown, if it is not too dark, will enhance contrast as well as doing a modicum of blue-blocking.
* Rose also increases contrast and blue-blocking offering a niche in car use.
In summary, aviators' sunglasses should:
* be glass or polycarbonate;
* transmit not less than 25% of available light;
* not distort colors, distances or shapes;
* nullify the blurring effect of short-wave reflected blue;
* have their adverse effect on visual acuity well understood; and
* not be worn under conditions of diminished light.
As an aside, I bought a pair of glass Serengettis with a brown tint for nearly $AUD300. I didn't like the weight of the glass lens at all, and the brown tint, while it was good for glare, made the green information on EFIS a little hard to see when I transistioned to EFIS. In addition the inside of the lens was highly relfective, so as I was sitting in shadow (in the cockpit) looking out at a bright field (like a cloud deck from above) they gave me a perfect image of my eyes looking back at me (reflected from the inside of the lens). That was difficult to ignore. I now fly with a pair of $AUD15 plastic sunnies I bought from a Chemist and I am much happier with them.
In Australia pilots may claim one pair of sunnies per year at tax time.
sources:
-CAA (Australia) Aviation Safety Digest (ASD) 150 (1991)
-ASD 136 (Autumn 1998)
-ASD 133
-CASA's Flight Safety Australia (Sept. 1997)
Copies of all of these articles are available for free if you contact (Australia'a CASA or BASI)
