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LEDs As Airborne Indicators  
User currently onlineSingapore 777 From Australia, joined May 1999, 1015 posts, RR: 3
Posted (10 years 1 month 3 weeks 2 days 9 hours ago) and read 1559 times:

A simple question - what were some of the problems associated with early LEDs as airborne indicators?

Thanks in advance for the replies! Much appreciated!  Smile

8 replies: All unread, jump to last
 
User currently offlineCancidas From Poland, joined Jul 2003, 4112 posts, RR: 11
Reply 1, posted (10 years 1 month 3 weeks 2 days 6 hours ago) and read 1478 times:

i'm not sure what you mean. are you asking why LED lights are not used in aviation more often? actually, they are. i have seen quite a few aircraft, bit GA and airliners using LEDs for position (anti-collision) lights. the strobes, well they have to be strobes. however, the reason LEDs are not used in landing/taxi lighting is twofold. partly, it's the same reason you won't find LED lamps for your house. they just don't put out good white light. the other is that they are not bright enough for use as landing lights.


"...cannot the kingdom of salvation take me home."
User currently offlineAirplay From , joined Dec 1969, posts, RR:
Reply 2, posted (10 years 1 month 3 weeks 2 days 5 hours ago) and read 1471 times:

they just don't put out good white light. the other is that they are not bright enough for use as landing lights.

Many designs for aircraft lighting now use high powered LED arrays. I have seen then in general cabin illumination, panel lighting, logo-lights and other external lighting. Its only a matter of time before we see an LED landing light.

The engineering hurdles have consisted primarily of heat dissipation but it is being addressed.

Also, additional optics can make relatively low brightness LEDs as bright as you want them to be.


User currently offlineBandA From United States of America, joined Aug 2004, 338 posts, RR: 0
Reply 3, posted (10 years 1 month 1 week 1 day 7 hours ago) and read 1327 times:

Yeah the brightness of an LED shouldnt be an issue for too long... they already use LEDs in strobes on police cars around here... they are very bright and ommit accurate colors...


"They [Terrorists] never stop thinking about new ways to harm our country and our people, and neither do we." - GWB
User currently offlineN328KF From United States of America, joined May 2004, 6484 posts, RR: 3
Reply 4, posted (10 years 1 month 5 days 7 hours ago) and read 1223 times:

Som military aircraft use LEDs to emit a very pale blue light at night, to make the aircraft blend in with darkness better.


When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' T.Roosevelt
User currently offlineMD11Engineer From Germany, joined Oct 2003, 14026 posts, RR: 62
Reply 5, posted (10 years 1 month 5 days 7 hours ago) and read 1222 times:

Considering the amount of "peanut bulbs" (387, 1864, etc) we change every day, I wonder why LEDs are not used more in cockipt indication lights. Also I can´t imagine LEDs getting as hot as those light bulbs.

Jan


User currently offlineKlaus From Germany, joined Jul 2001, 21461 posts, RR: 53
Reply 6, posted (10 years 1 month 5 days 6 hours ago) and read 1215 times:

MD11Engineer: Considering the amount of "peanut bulbs" (387, 1864, etc) we change every day, I wonder why LEDs are not used more in cockipt indication lights. Also I can´t imagine LEDs getting as hot as those light bulbs.

No, especially the halfway modern LEDs use a lot less power than normal light bulbs. (And produce less heat in return.)

But (reliable) white LEDs aren´t around for all that long yet, and they´re still more expensive than the classic red, green and yellow ones.

You´d probably have to redesign the switches or instruments to accomodate the LEDs instead of conventional bulbs as well, so I guess it may not be seen as a high priority.

And you´ll lose the possibility to determine the status of an indicator light after a crash (characteristically broken filament). LEDs leave no such trace. Maybe that´s another reason, but I could understand why it might not be publicized a lot...


User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 7, posted (10 years 1 month 5 days 4 hours ago) and read 1201 times:

On one aircraft I'm very familiar with, we eventually got LED position lights. The fun part was that these LEDs were white until lit - i e, you couldn't see the colour of them when they were off! And naturally, the previously red/green glass was clear as well. This created a need for new procedures in maintenance that were not expected, in order to make sure the red colour lights went on the left side as the green lights were right and would have been wrong.  Big grin


I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineKlaus From Germany, joined Jul 2001, 21461 posts, RR: 53
Reply 8, posted (10 years 1 month 5 days 3 hours ago) and read 1195 times:

Yeah... you sometimes have to power them up to see what kind you´ve got.  Wink/being sarcastic

Since coloured LEDs generate only the "right" colour anyway (through the properties of the semiconductor materials), there´s no need for a filter to mask the other wavelengths. And that´s another reason why they´re more efficient: A normal lamp wastes energy on creating the full spectrum, even though the filters will block most of it again.


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