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backup cockpit lighting



 
 
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  #11  
Old December 21st 04, 11:50 PM
Stan Gosnell
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"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
  #12  
Old December 21st 04, 11:56 PM
Jay Beckman
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"Bob Gardner" wrote in message
...
This is an IFR newsgroup, and I assume that everyone is using
black-and-white charts.


Mea Culpa..

I didn't take this into consideration, sorry. I read most of the aviation
newsgroups in order to pick up as much info as possible and I sometimes
forget their specifc focus.

The usual argument against red light is that it washes out detail on
sectionals. The AIM does not give a glowing endorsement of red lighting
and emphasizes the need for white light. Green is a nice alternative. I
never used red light in all my years of flying IFR, but that is just a
personal peccadillo. I found that turning white cockpit and instrument
lighting down to an irreducible minimum worked well for me. I also used
diffused white light to illuminate approach plates.


I haven't done much night flying since my required night training but I
agree with how you do it. I found myself only reaching for a point light
source when I needed to double check something in the A/FD.

I note that the chemical light sticks designed for emergency use glow
green, but that might just be a question of available chemicals.


IIRC, I've seen them in different colors...but mostly the bright green.

Googling "night vision _ green" gets a lot of hits that refer to night
vision goggles. I hope and pray that none of our newsgroupie friends are
using NVGs. That appears to have driven the military to go to green instead
of red.

Bob


Thanks Bob...

In the future, I'll try to be more aware of which group I'm in before I wade
in.

Regards,

Jay Beckman
PP-ASEL
Chandler, AZ


  #13  
Old December 22nd 04, 12:05 AM
Jay Beckman
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"Stan Gosnell" wrote in message
...
"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


Stan,

Thanks very much. Interesting stuff about helo flying.

Jay B


  #14  
Old December 22nd 04, 12:32 AM
Stan Gosnell
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"Jay Beckman" wrote in
news:gS1yd.12219$ry.11166@fed1read01:

"Bob Gardner" wrote in message
...
This is an IFR newsgroup, and I assume that everyone is using
black-and-white charts.


Bad assumption. Jepp IFR charts aren't black and white, and many of us
use Jepps.

In the future, I'll try to be more aware of which group I'm in before
I wade in.


Don't worry about it. There are many threads much further off topic than
this. Anyone who doesn't have VFR charts along on an IFR flight is
negligent, IMO. Sometimes you need more information than is shown on IFR
charts, and lighting applies to all phases of flight.

--
Regards,

Stan
  #15  
Old December 22nd 04, 12:55 AM
Bob Gardner
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Not a biggie...I wasn't taking you to task for where you posted, just noting
that sectionals do not play a big part in IFR flying...although they should
always be available.

Since I never used red or green, the colors on Jepp low altitude charts
didn't affect me. The important info is in blue anyway.

Gotta look up some of those wild chemical stick colors for New Year's Eve!!!

Bob

"Jay Beckman" wrote in message
news:gS1yd.12219$ry.11166@fed1read01...
"Bob Gardner" wrote in message
...
This is an IFR newsgroup, and I assume that everyone is using
black-and-white charts.


Mea Culpa..

I didn't take this into consideration, sorry. I read most of the aviation
newsgroups in order to pick up as much info as possible and I sometimes
forget their specifc focus.

The usual argument against red light is that it washes out detail on
sectionals. The AIM does not give a glowing endorsement of red lighting
and emphasizes the need for white light. Green is a nice alternative. I
never used red light in all my years of flying IFR, but that is just a
personal peccadillo. I found that turning white cockpit and instrument
lighting down to an irreducible minimum worked well for me. I also used
diffused white light to illuminate approach plates.


I haven't done much night flying since my required night training but I
agree with how you do it. I found myself only reaching for a point light
source when I needed to double check something in the A/FD.

I note that the chemical light sticks designed for emergency use glow
green, but that might just be a question of available chemicals.


IIRC, I've seen them in different colors...but mostly the bright green.

Googling "night vision _ green" gets a lot of hits that refer to night
vision goggles. I hope and pray that none of our newsgroupie friends are
using NVGs. That appears to have driven the military to go to green
instead of red.

Bob


Thanks Bob...

In the future, I'll try to be more aware of which group I'm in before I
wade in.

Regards,

Jay Beckman
PP-ASEL
Chandler, AZ



  #16  
Old December 22nd 04, 04:48 PM
Stan Prevost
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"Stan Gosnell" wrote in message
...
"Jay Beckman" wrote in
news:CKRxd.11974$ry.7550@fed1read01:

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



some stuff snipped

The human eye is much more sensitive tou green light than red
light.

I need to preserve my night vision to some extent, because I'm
not always landing to a brightly lit runway.

I prefer narrow-band sources,
and red is the least effective of all the colors.


There are two issues here, and Stan (the other Stan) has touched on both.
One is simply vision within the cockpit, and for this, any color of light
will do, except that the color should not compromise readability of
instruments and charts. Red is not the best choice for this. The other
issue is vision outside the cockpit, which is still very important for IFR
flight, as Stan pointed out. Light color and intensity should be chosen to
allow good in-cockpit visibility without compromising outside visibility.

The physiological basis for night vision (dark-adapted, or scotopic vision)
is primarily the characteristics of the retinal photoreceptors called rods.
These are indeed more sensitive to shorter wavelengths, and, at low
illumination levels, less light intensity should be required if a green
light is used. But true dark adaption is based on the presence of a
light-sensitive pigment in the rods called rhodopsin. This pigment is
naturally synthesized in the rods but is destroyed by light. Dark adaption
is the process of allowing the concentration of rhodopsin to increase by not
allowing its destruction by light. It takes 45 minutes or so for it to
reach maximum levels, but can be destroyed by a few seconds of exposure to
higher light levels. Red light does not have the destructive power on
rhodopsin that shorter wavelengths have, and that is why red light has long
been favored when maximum preservation of night vision is required. Blue
and green will have a stronger destructive effect.

The cones also become somewhat dark-adapted using other pigments, and they
respond much more quickly, like 5-7 minutes.

However, a balance must be struck. I think that most of our aviation vision
occurs in the so-called mesopic region, in which both rods and cones
contribute significantly. Dim white light or light of other colors will
allow good readability of instruments and charts while allowing reasonable
dark adaptation. The main thing is to avoid bright light.

My own experience is that red works well for me except on sectionals. Some
of the red lamps I use are a little brighter than I would like but I don't
find that they mess up my adaption even when falling directly on my face
briefly. White light does mess me up unless it is very dim. I haven't used
other colors. I keep a little white Photon microlight handy for looking at
sectionals when needed, but it does mess up my vision because it is so
bright.

One good reference is "Night Vision In Military Aviation", by the USAF
School of Aerospace Medicine:

http://www.brooks.af.mil/web/af/cour...tures/UNV7.doc


Stan


  #17  
Old December 22nd 04, 10:11 PM
Mitty
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I keep a little white Photon microlight handy for looking at
sectionals when needed, but it does mess up my vision because it is so
bright.

The Photon III has low/medium/high settings as well as some useless flash modes.
The mode is kind of a pain to change, but once set it stays on that mode. Try
one of these set at medium or low intensity. Also, with the "covert" snout your
eyes are shielded from directly viewing any of the emitted light.
  #18  
Old December 22nd 04, 10:30 PM
Stan Prevost
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"Mitty" wrote in message
...

I keep a little white Photon microlight handy for looking at sectionals
when needed, but it does mess up my vision because it is so bright.

The Photon III has low/medium/high settings as well as some useless flash
modes. The mode is kind of a pain to change, but once set it stays on that
mode. Try one of these set at medium or low intensity. Also, with the
"covert" snout your eyes are shielded from directly viewing any of the
emitted light.


I haven't tried one of those, sounds useful. It must have the same
controller as the Photon Fusion headlamp, with all the hard-to-change modes
and useless flashing modes. But once you get it into the right mode, it's
great.

Stan


  #19  
Old December 22nd 04, 10:47 PM
Stan Gosnell
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"Stan Prevost" wrote in
:

My own experience is that red works well for me except on sectionals.
Some of the red lamps I use are a little brighter than I would like
but I don't find that they mess up my adaption even when falling
directly on my face briefly. White light does mess me up unless it is
very dim. I haven't used other colors. I keep a little white Photon
microlight handy for looking at sectionals when needed, but it does
mess up my vision because it is so bright.


One problem for me with red light is that I have about a dozen gauges
with red lines and red areas. Red light doesn't help much in seeing
these. If the instrument lights fail and I have to rely on my own light,
red ain't gonna cut it, because there is likely to be lots of stuff going
on, and I need to know if I'm approaching limits on the engines, RPM,
torque, oil temps and pressures, hydraulic systems, and everything else.
I need to be able to see at a glance where the needles are in relation to
the redlines. If red is adequate in your aircraft, then use whatever
works for you. I've tried red, and don't like it.

--
Regards,

Stan
  #20  
Old December 22nd 04, 11:00 PM
Stan Prevost
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"Stan Gosnell" wrote in message
...

One problem for me with red light is that I have about a dozen gauges
with red lines and red areas. Red light doesn't help much in seeing
these. If the instrument lights fail and I have to rely on my own light,
red ain't gonna cut it, because there is likely to be lots of stuff going
on, and I need to know if I'm approaching limits on the engines, RPM,
torque, oil temps and pressures, hydraulic systems, and everything else.
I need to be able to see at a glance where the needles are in relation to
the redlines. If red is adequate in your aircraft, then use whatever
works for you. I've tried red, and don't like it.


Those are very good reasons for not using red in your aircraft. That has
not been a problem in the ones I fly.



 




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