Red Lights in Cockpits
Name: Matt M.
Date: September 2003
Why do they put red lights in airplane cockpits?
Red light is used in cockpits for night flying because it is the least detrimental to the
pilot's night vision. You have noticed that it takes a period of accommodation for your
eye to see well in the dark after leaving a lighted room. That accommodation is easier
after being exposed to red light.
There are two problems with the red light in the cockpit. First the human eye is less
sensitive to red light than to any other color of the spectrum. Second, the pilot cannot
see red print (which is sometimes used on navigation charts) under the red light. To
solve this second problem the cockpits often have a small, narrow-beamed white light that
is used sparingly. Often the pilot closes one eye when using the white light to preserve
the night adaptation of that eye.
The human eye sees green the best. So the important information (like numbers on
instruments) are generally green (or sometimes yellowish green) in color.
Maintaining good vision inside and outside the cockpit... even at night... is important
to a pilot.
Red light minimally triggers the eye's autonomic contraction of the iris, so that the pilot
can continue to see dim lights such as planes etc. outside.
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Update: June 2012