hagiograph From United States of America, joined Jun 2011, 9 posts, RR: 0 Posted (7 months 2 weeks 7 hours ago) and read 1962 times:
As I am finding myself sitting on more jets these days with little more to do than stare blankly off into space I have begun noticing the differences in cabins and their fixtures. Recently on a flight back home on a Delta 757 (if I recall correctly) I noticed the following type of exit sign:
and it looked like it was unlit throughout the flight. All the similar signs to this also looked unlit. Are these simply "electrical" lightbulb-based lights that are activated during an emergency or are they supposed to 'glow' during the entire flight? I know some emergency exit signage in various other places looks like it has some "glow-in-the-dark" capability but this type of light didn't look like that.
Mender From United Kingdom, joined Feb 2004, 227 posts, RR: 0 Reply 1, posted (7 months 2 weeks 3 hours ago) and read 1962 times:
They are activated by the emergency lighting system and are simple electrical bulbs, not photoluminescent. You can find aircraft with photoluminescent floor path lighting which requires less maintenance than conventional 'bulbs'.
hagiograph From United States of America, joined Jun 2011, 9 posts, RR: 0 Reply 2, posted (7 months 2 weeks 1 hour ago) and read 1962 times:
Mender, thanks! I was always curious why some signs appear to be "electric lights" or bulbs and some are those little red block "tritium signs" which, if I understand correctly, contain some amount of radioactive material and still others are the photoluminescent type of lighting that charges from incoming light and then glows a long time.
FlyDeltaJets From United States of America, joined Feb 2006, 1631 posts, RR: 3 Reply 3, posted (7 months 1 week 3 days 13 hours ago) and read 1962 times:
Quoting hagiograph (Reply 2): if I understand correctly, contain some amount of radioactive material
1337Delta764 From United States of America, joined Oct 2005, 5819 posts, RR: 2 Reply 4, posted (7 months 1 week 2 days 23 hours ago) and read 1962 times:
I wonder, which particular aircraft types have tritium signs? I know MD-80s have them, and I think some non-Signature Interior 767s have them as well (the white on red ones). What other aircraft types have them?
The Pink Delta 767-400ER - The most beautiful aircraft in the sky
HAWK21M From India, joined Jan 2001, 31228 posts, RR: 58 Reply 6, posted (7 months 1 week 2 days 4 hours ago) and read 1962 times:
Quoting Dalmd88 (Reply 5): The electric signs and path way lights are powered by dedicated battery packs that are powered on when armed and the aircraft power is lost.
1337Delta764 From United States of America, joined Oct 2005, 5819 posts, RR: 2 Reply 8, posted (7 months 1 week 21 hours ago) and read 1962 times:
Quoting hagiograph (Reply 7): I assume that the picture of the one I was looking at is NOT one that contains tritium or radioactive material, correct?
No, that one contains incandescent bulbs. I have seen them lit once while we were on the ground at ATL at one point. Typically, tritium signs are white on red, rather than red on white like image you posted.
The Pink Delta 767-400ER - The most beautiful aircraft in the sky
AA737-823 From United States of America, joined Mar 2000, 5381 posts, RR: 11 Reply 9, posted (7 months 1 week 17 hours ago) and read 1962 times:
Quoting 1337Delta764 (Reply 4):
I wonder, which particular aircraft types have tritium signs? I know MD-80s have them, and I think some non-Signature Interior 767s have them as well (the white on red ones). What other aircraft types have them?
Some of the late model 737-200's had them, and I think LOTS of the 737-Classics had them, but for the NG, they reverted back to incandescent light bulbs. Evidently all of United's Global Service whiners were getting ankle cancer when they sat in the exit row window seats...........
Quoting hagiograph (Reply 7): I assume that the picture of the one I was looking at is NOT one that contains tritium or radioactive material, correct?
Indeed, they're incandescent in that assembly, and much smaller than a pencil eraser. They also burn out a lot, and run at just 6 volts DC. They're seriously tiny- maybe the diameter of the tip of a small headphone plug.
hagiograph From United States of America, joined Jun 2011, 9 posts, RR: 0 Reply 10, posted (7 months 1 week 9 hours ago) and read 1962 times:
Quoting 1337Delta764 (Reply 8): No, that one contains incandescent bulbs. I have seen them lit once while we were on the ground at ATL at one point. Typically, tritium signs are white on red, rather than red on white like image you posted.
Quoting AA737-823 (Reply 9): Indeed, they're incandescent in that assembly, and much smaller than a pencil eraser. They also burn out a lot, and run at just 6 volts DC. They're seriously tiny- maybe the diameter of the tip of a small headphone plug.
1337Delta764 From United States of America, joined Oct 2005, 5819 posts, RR: 2 Reply 11, posted (7 months 1 week 5 hours ago) and read 1962 times:
Quoting AA737-823 (Reply 9): Some of the late model 737-200's had them, and I think LOTS of the 737-Classics had them, but for the NG, they reverted back to incandescent light bulbs. Evidently all of United's Global Service whiners were getting ankle cancer when they sat in the exit row window seats...........
Where are the tritium signs located on 737 Classics? Every 737 Classic I have been on has the same type as that 757 sign in the OP's post.
The Pink Delta 767-400ER - The most beautiful aircraft in the sky
Mender From United Kingdom, joined Feb 2004, 227 posts, RR: 0 Reply 12, posted (7 months 6 days 13 hours ago) and read 1962 times:
Quoting 1337Delta764 (Reply 11): Where are the tritium signs located on 737 Classics? Every 737 Classic I have been on has the same type as that 757 sign in the OP's post.
I have seen at least one 757 with some tritium signs on the hatracks next to the exits. Why, I've no-idea, but it had incandescent bulb signs in the ceiling as per the OP and small tritium sign in the doorways.
Thinking about it, the aircraft wasn't being operated by the original customer who had specified the aircraft at build. Maybe some of the lavs and galleys had been re-located so that it had the same layout as the rest of the aircraft in their fleet. In this instance it would be easier to install tritium exit signs rather than wiring in new incandescent signs where they hadn't previously been installed.
AA737-823 From United States of America, joined Mar 2000, 5381 posts, RR: 11 Reply 13, posted (7 months 1 day 22 hours ago) and read 1962 times:
Quoting 1337Delta764 (Reply 11): Where are the tritium signs located on 737 Classics? Every 737 Classic I have been on has the same type as that 757 sign in the OP's post.
Floor-level guidance signs, I.E., the floor-level signs at the overwing exits, as well as 1R/1L and 2R/2L doors, and the center aft guidance light, mounted to the base of the F/A jumpseat.
Quoting Mender (Reply 12): I have seen at least one 757 with some tritium signs on the hatracks next to the exits. Why, I've no-idea, but it had incandescent bulb signs in the ceiling as per the OP and small tritium sign in the doorways.
The tritium units last a long time with virtually no maintenance, which compares favorably to the incandescent equivalent, which requires at least one of its 21 bulbs to be replaced pretty dependably at every monthly check.
A36001 From Australia, joined Sep 2012, 88 posts, RR: 0 Reply 14, posted (7 months 22 hours ago) and read 1962 times:
Hi all,
Why is the floor lighting red at a exit? Shouldn't this be green, given that green in most parts of natural thinking is a go or safe to go signal. In a dire emergency I would of thought most people would respond better if they see what they normally see. Meaning... red light = no entry - green light = safe to go.
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 15, posted (7 months 20 hours ago) and read 1962 times:
Quoting A36001 (Reply 14): Why is the floor lighting red at a exit? Shouldn't this be green, given that green in most parts of natural thinking is a go or safe to go signal.
The US used, and still uses, red for exit signs and that carried over into aircraft exit lighting.
The 787 switched over to the international standard green.
Fabo From Slovakia, joined Aug 2005, 1111 posts, RR: 1 Reply 17, posted (7 months 12 hours ago) and read 1962 times:
I once read a good discussion on this, might be here on a-net. IIRC red was deemed as the color that is easiest to notice. Same reason fire engines are usually red, btw.
The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 18, posted (7 months 9 hours ago) and read 1962 times:
Quoting HAWK21M (Reply 16): Whats the US justification for this...
At this point, same reason the US still uses feet/inches/pounds...because they've always done it that way. I have no idea why it started that way. But if you go into any US building the exit signs will almost universally be red; that's just what colour you expect to see for exits here.
The FARs as they currently stand required red for several portions of exit markings (e.g. the word "EXIT" on the door, the arrow showing which way the handle should turn to open the door) and that seems to be carried over into everything exit related.
Sponsor Message: 
From United States of America, joined Jun 2011, 9 posts, 
From United Kingdom, joined Feb 2004, 227 posts, 
From India, joined Jan 2001, 31228 posts, 
From Australia, joined Sep 2012, 88 posts, 
From Canada, joined Jan 2006, 12709 posts, 
From Slovakia, joined Aug 2005, 1111 posts, 
Sponsor Message: 
Printer friendly format
