Guidance Notes on the use of sunglasses by pilots
Sunglasses are an important piece of protective equipment in the cockpit environment. The following offers guidance to pilots purchasing sunglasses.
The tint should be neutral in colour. In practice, grey or brown are acceptable. The tint should be no darker than 80% absorption. A graduated tint (darkest at the top of the lens and lightening towards the bottom) may be useful.
Photochromic lenses react with UV radiation by darkening. As the cockpit windshield is designed to block the transmission of UV light, these lenses will not work as effectively in the cockpit environment. The use of these sunglasses is therefore discouraged.
Polarised lenses reduce the amount of light passing through the lens by selective filtering of certain electromagnetic spectral planes. These lenses can cause distortion patterns from certain laminated cockpit windshields. They can also alter cloud appearance and reduce ground reflections useful for VFR pilots. The use of these sunglasses is therefore discouraged.
All frames should be well fitting and be large enough to allow sufficient protection from oblique sunlight. All pilots requiring a spectacle prescription must have one clear pair of correcting lenses but can have prescription sunglasses as their second pair. The wearing of plano sunglasses on top of prescription glasses is not acceptable. For night flying, it is recommended that both pairs of prescription glasses are without tint.