backup cockpit lighting

"Jay Beckman" wrote in
news:CKRxd.11974$ry.7550@fed1read01:

What do you find superior about green instead of red light?

Using red light means LCD displays don't show up well. IFR
charts, which are blue, don't show up very well. Sometimes I
need to see a VFR chart for something, and all the magenta
washes out completely.

The human eye is much more sensitive tou green light than red
light. That's one reason all night vision devices use green.
The military uses green for all night cockpit lights. I notice
that it takes much less light to be able to see almost anything
using green light. Red is just traditional, from the time when
little actual research had been done, and the availability of
light with narrow wavelengths was unknown. Red was easy to do,
and had some small effect in reducing the loss of night vision.
Now it's possible to buy LEDs with a very narrow band of
wavelengths, and they don't affect your vision in other
wavelengths. White, OTOH, is a broadband mix of wavelengths
and will affect your night vision across the spectrum.

I need to preserve my night vision to some extent, because I'm
not always landing to a brightly lit runway. I land to
helipads that have lights, but may not be very well lit, and I
need to be able to find platforms in the middle of the ocean.
If you're flying airplanes between IFR runways, then white
light probably won't hurt much. I prefer narrow-band sources,
and red is the least effective of all the colors.

--
Regards,

Stan