For most people sunglasses fulfill one, or both, of two purposes: as a fashion statement to look "cool," and to help cope with bright sunlight. The choices available are seemingly endless, and can range from polarized to photo chromic to colorful tints and shades.
But for pilots sunglasses are much more than a fashion statement. Sunglasses help safeguard a pilot's most important sensory asset in flight - vision. A quality pair of sunglasses is essential in the cockpit environment to optimize visual performance. They help reduce the effects of harsh sunlight, decrease eye fatigue, and protect ocular tissue from exposure to harmful solar radiation. Additionally, they protect the pilot's eyes from impact with objects such as flying debris from a bird strike, sudden decompression or an aerobatic maneuver.
The choice of tints for sunglasses is almost infinite, but the three most common tints are gray, gray-green, and brown, any of which would be an excellent choice for the aviator. Gray is recommended the most because it distorts color the least. Many pilots, however, report that gray-green and brown tints enhance vividness and minimize scattered blue and violet light, thus enhancing contrast in hazy conditions.
For pilot, sunglass lenses should screen out only 70-85% of visible light and not appreciably distort color. Any tints that block out more than 85% of visible light are not recommended for pilots due to the possibility of reduced visual acuity which could result in difficulty seeing the flight instruments, written checklists and data inside the cockpit.
While polarized lenses are very popular, they are not recommended for use in the aviation environment. While they are useful for blocking reflected light from horizontal surfaces such as water or snow, polarization can reduce or eliminate the visibility of flight instruments that incorporate anti-glare filters like the new glass cockpit environments. These polarized lenses may also interfere with visibility through an aircraft windscreen by enhancing striations in laminated glass and mask the sparkle of light reflected off of another aircraft's fuselage or wings, which in turn can reduce the ability of pilots to "see-and-avoid" other aircraft.
Photo chromic lenses automatically darken when exposed to ultraviolet light and become lighter in dim light. The majority of the darkening takes place within 60 seconds, while lightening may take several minutes. While most photo chromic lenses can get as dark as regular sunglasses, direct sunlight or warm temperatures above 70 degrees Fahrenheit can seriously limit their ability to darken, and reduced ultraviolet light exposure in a cockpit can further limit their effectiveness. Further, the faded state of photo chromic lenses may not be clear enough to be useful when flying in clouds or at night.
The selection of frames is more a matter of personal preference; however, bayonet style temples are the most popular because they are easy to put on or remove while wearing headsets or a helmet. Smaller lenses may not be practical because they allow too much visible light and ultraviolet radiation to pass around the edges of the lenses. Finally, use of a strap is recommended to prevent the sunglasses from being accidentally dislodged.
In summary, while sunglasses may add to the mystique of a pilot, sunglasses are the most important method to protect the pilot's eyes from glare associated with bright sunlight and the effects from exposure to solar radiation. Since sunglasses are such an important asset, careful consideration should be used when selecting an appropriate pair for flying.
Since 1982, Randolph Engineering has been standard issue for U.S. military pilots. Not only are their sunglasses made in the USA, but quality of materials and the precision of manufacturing the Randolph Aviator, their flagship product, actually surpass the exacting standards of the military. So when NASA Astronauts lift off the launch pad and head for outer space, Randolph is right there with them. When America's Top Gun Pilots step into the cockpit of a sleek jet fighter or the magnificent Stealth Bomber, Randolph is the priceless pair of sunglasses that helps those pilots safely navigate the skies.
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