[Don]

When I bought my tail kit I also bought Whelen lights from Van's. I have no doubt these meet or exceed the FARs. I've been considering switching to LED lights (position lights and strobes) produced by Thor, LLC (www.thorllc.net). I first encountered Frank and his wife at the Virginia EAA Fly-In and I encountered them again at Oshkosh last month. The reason I'm considering changing are the Thor lights weigh less than a pound, they eliminate the "controller" for the strobes that's heavy and produces extraneous RF noise (instead the Thor units have a small circuit boad that's installed near the lights), and they offer the promise of better reliability.

When I asked Whelen about their plans for an LED lighting system they got downright defensive and declared that the technology for 12v LEDs wasn't capable of meeting the FARs. They claimed no one could use 12v LEDs and comply with the FARs. They said the LED maker they were familiar with (no names were used) had a disclaimer on their website about not promising to meet the FARs. Finally, then they played the emotional card about how this is all about safety and why would I consider anything that isn't thoroughly proven.

As I evaluate Whelen's statements, I see no disclaimer on Thor's website. In fact I also see Thor specifically states, "our light systems [are] built to meet and exceed all FAA regulations", which I read as a warranty of sorts, provided you install the lights correctly. When they tried to win me over based on an emotional argument, they've lost most of my respect. I want to see data in an argument - when I want my heart strings plucked I'll watch a sappy movie.

So, my question is this, when you guys inspect an airplane I'm sure you evaluate the lighting system for compliance with the FARs. I'd expect you'd base issuance of the airworthiness certificate and the day/night limitations in part on what you find. If I go with the Thor, LLC lights will I be setting myself up for trouble when I apply for an airworthiness certificate? Or, will Thor's statement plus your inspection be enough to satisfy this part of the inspection?

Don

 

[gmcjetpilot]

Experimental lights

I had the same question so I went with a Aeroflash "traditional" system. Here is the short two part answer I found:

Part one - You are experimental. Your lights can be experimental. Done

Part two - Experimental LED nav/strobes probably don't meet the FAR's, see part 1.​

The measurement of light intensity, color, coverage is a fairly complex archaic convoluted science. I am pretty sure experimental light makers don't do more than stand back and go, looks good. From what I know about the requirements, just by inspection I can see many (all) don't meet the requirements. The one you mention looks questionable in my opinion.

The other side of the coin is the coverage, color and / or intensity is too much. Too bright and too much coverage with a NAV light is NOT GOOD. You want a standard so all planes look the same from similar direction and distance and angle.

I looked into making my own NAV lights and talked to a guy who tried to make LED nav lights that met the FAR's. He was very scientific and used the FAR's as a guide and optical and electrical characteristics of LED's. He took an engineering approach. I was left with the opinion that making LED's per the FAR is difficult (12/24v). If anything the measurement and calibration is hard with out optical lab.

The 12v and 24v thing? No doubt it is what LED's are available and the technology at this time. Frankly most LEDs run down in the 2-3 volt range, so I am not sure about that.

I have talked to Whelen and they gave me the same info, some was wrong as applied to experimentals, especially strobes (see part 1 above). You could if you wanted get a step up 12 to 24 volt converter. However spending $200 on a 12/24v converter and very expensive 24v Whelen NAV lights will cost too much and be heavier. I get the feel Whelen is just jealous that we have the freedom we do. No doubt they went through grief getting their 24v LED Nav lights certified. BF Goodrich also has LED lights.

Right now the only inexpensive NAV light that works on 12V that looks like it should work is a taillight (white) NAV light. You can get white LED's that are super bright AND have a wide range. The catch 22 of LED's is as intensity goes up the coverage or angle narrows. Also, finding red and green LED's in the correct wave length, intensity and angle is not easy (impossible at this time). Therefore you get these 20 or 30 LED monsters. The good news LED technology keeps improving. Someday they'll have single LED's that will fill the bill, but right now it's marginal in my opinion, at least in the 12v according to Whelen.

If you want to use your experimental NAV lights go ahead (see part 1). You are experimental and so are your lights.

If you are into meeting FAR 23 and other FAR's that apply to certified planes (as I am when possible), than get "real" NAV lights.

Bottom line, Whelen is probably right, but so what, we don't have to buy there stuff. I have Aeroflash strobes/navs. Whelen told me that they where not good or acceptable. I checked with the FAA, more than once and they are fine even if the Joules are down a little (see part 1 above). The answer was "you are experimental, right?", "your plane is not certified, right?".

If you want to have a high level of confidence your lights meet the regs (if that is what you want), than the only way to assure this is buy a certified system, like Whelen or test what you install. The latter test may be hard to do for an individual. That's probably where Whelen is coming from, we have done the test so buy our stuff. The few amps and pound of savings LED's would save me, was not enough for me to use them, at this time.

As far as DAR's, that is up to them, but I have been told they don't get into the lights. According to the FAA inspectors I have talked to it would not be an issue. Remember YOU the builder certify the plane for NIGHT FLIGHT with a log book endorsement, not the FAA or DAR.

 

[Mel]

The DAR will inspect your lighting system and advise you accordingly. This is just a courtesy. Your operating limitations will state:
"After completion of phase I flight testing, unless appropriately equipped for night and/or instrument flight in accordance with part 91.205, this aircraft is to be operated under day only VFR."
This puts the monkey on your back. If your lighting system meets 91.205, then you are good to go. In the real world, if your system looks like it meets 91.205, no one is going to question it. One of the few things people overlook is the light coverage. If your wingtip strobes cannot be seen from the rear, then you must have a tail strobe as well.

 

[Davepar]

The measurement of light intensity, color, coverage is a fairly complex archaic convoluted science. I am pretty sure experimental light makers don't do more than stand back and go, looks good.

From the CreativAir web site: "If assembled properly, the LED Position Lights meet or exceed the FAA illumination requirements in all directions. Step-by-step instructions on how to confirm FAA illumination compliance are included in the kit."

 

[az_gila]

Ask them a specific question...

From the CreativAir web site: "If assembled properly, the LED Position Lights meet or exceed the FAA illumination requirements in all directions. Step-by-step instructions on how to confirm FAA illumination compliance are included in the kit."

The key is to ask them specifically "have you tested the instalation to see if it meets the FAR requirements?"

From some earlier e-mail traffic on the subject, the answer seemed to be "I copied what Whelen did and used the same LEDs"

Not quite what you want if you want regulatory compliance.
Did Whelen select high power LEDs from the standard part number? - more $$ for selected parts.
Did they copy the exact light reflectivity of the surrounding materials? - makes a big difference to the light distribution.

Note the the FAR requirements have very specific output requirements in the "overlap" area where two nav lights can be seen.

I agree with George - the tests need to be done on a similar installation to the one you are constructing....

Given my knowledge from a long time ago past job (Chief Engineer for a light measuring equipment company) - these are not trivial measurements - but could be performed with the correct, calibrated equipment in a dark room.

gil in Tucson

 

[gmcjetpilot]

You are the Boss

From the CreativAir web site: "If assembled properly, the LED Position Lights meet or exceed the FAA illumination requirements in all directions. Step-by-step instructions on how to confirm FAA illumination compliance are included in the kit."

That is fine, I would like to read it. The info is available from the FAA and found in several references, FAR's and Advisory Circular (AC). It's not that I don't care, but it does not matter it is experimental. If it is close it is good enough.

The part about exceeding the REGS means what? Well you don't really want to exceed the coverage, angles and intensities. Will it create a safety hazard if its a little too bright? No. If coverage is too great it could be a little confusing to other planes I guess. Again no big deal.

On the fine points of really measuring light intensity, angles, wavelength and coverage, is it seems really complex. If you look at the regulations, specs and AC it is pretty complex physics, at least to me. The units are crazy.

Certainly you can SWAG it. Most guys get about as scientific as "I turned it on in my garage, and it was REALLY BRIGHT! I walked out side, and I could still see it DOWN THE STREET!" That is good enough. Good enough for me, but if you really want to know or have a "certified NAV Strobe" light system it will take a lot more than that. To be honest some of the experimental systems look suspect to me. For example:

-Strobes, with out a lens is not kosher. They have a max intensity at one plane not a all over scatter pattern of a bare strobe tube.

-NAV lights, some look like they just shotgunned as many LEDs as they could fit. Using LED's to do this is tricky. One "trick" I see is the use of reflectors, aka mirrors, since LED's are throwing a way light to the side. You also have to shield that extraneous side lobe light as well for proper coverage.​

Hats off to those who try to make their own. However those who sell them need to do some home work (no names mentioned). LED's are getting better, wider patterns and more intensity, while price drops.

Again it does not matter it is experimental and you (the builder) are boss. If you want to make your own system it would be fun. If you get into the regs and rules you will learn a lot. I started to look into it thinking you could throw LED's in there and it was more effort. I kind of wanted to know I had a "standard" system so I went with aeroflash.

LED's are getting better, wider patterns and more intensity, while price drops. When they can make a system that only needs one or a few LEDs I'll buy one. Right now those Christmas trees don't appeal to me. What if one burns out. Get a solder iron.

 

[Paul Thomas]

I think I had read about a cozy builder whose DAR would not issue an pass the airplane until the leds were removed. The gentleman had to remove them because once you start the paperwork with one DAR, you can't switch because you can't work out your issues.

I hate to bring something like this to the discussion because I can't recall the exact facts or where I read about it. Hopefully this will job someone's mind.

 

[rvpilot]

Is this the Kicker??

"After completion of phase I flight testing, unless appropriately equipped for night and/or instrument flight in accordance with part 91.205, this aircraft is to be operated under day only VFR."

If you look at 91.205, it calls for "approved position lights", "approved red or white anticollision lights". Since the exp LED systems are not approved, just meet or exceed the requirements, then do you really meet the above requirement as entered in the flight restrictions by the DAR???

 

[aadamson]

Nother option

This one also claims they meet the standard.

www.gs-air.com

I saw a Lancair Legacy at OSH, that had the strobes and nav lights embedded in the tip of the wings and then on the trailing edge of each wing at the tip, they had a row of white LED's... Nothing on the tail. Just goes to show you how much people with get away with...

 

[az_gila]

It is legal....

I saw a Lancair Legacy at OSH, that had the strobes and nav lights embedded in the tip of the wings and then on the trailing edge of each wing at the tip, they had a row of white LED's... Nothing on the tail. Just goes to show you how much people with get away with...

Alan... this is actually quite legal.

Quote from 23.1385
(c) Rear position light. The rear position light must be a white light mounted as far aft as practicable on the tail or on each wing tip.

And is similar to the "all-in-one" Whelen A600 units, which I have seen on large commercial jets.

But I bet they never measured the intensity in different planes, which is the "getting away with it" bit...

If you can't go to sleep, and want to know some physics, then this describes the "candles" of light intensity that the FAA uses in FAR 23. Note that the correct modern terminology is "candela", not "candles".

http://en.wikipedia.org/wiki/Luminous_intensity

gil in Tucson - reliving an old job....

 

[Fearless]

There was a builder in Lexington, KY who had trouble getting his navigation lights signed off on for night flying while getting his Cozy III inspected by a DAR. You can search this website to get the particular information - http://www.maddyhome.com/cozysrch/ - concerning the outcome. The DAR would only approve the Cozy III for day VFR flying. This particular builder was able to get approval from another district but I believe it had to do with a log entry for phase two testing in which this particular DAR's sign off wasn't required.

The RV-9A project that I acquired has the CreativAir LEDs included in it which I plan to use. I know that Mike Schipper has them on his 9A, you can see them on his website. He would have to speak to the fact if his DAR signed off on them.

 

[Mel]

I signed off Mike Schipper's airplane. If you will go back and read my previous post you will see that the DAR does not approve or disapprove your lighting system. The DAR has the authority to add any restrictins that he feels necessary for safety of flight, such as day VFR only. However, all the inspectors I know use the standard provision recommended by the FAA, which is exactly as my previous post.

 

[thallock]

As I read the regs, we are not required to have nav lights or strobes unless we fly at night, or under IFR. If we do fly at night, then our lights must meet the specs. The problem is deciding what meets the specs, which say "approved" without saying what "approved" means. If this means the manufacturer has to go to the FAA and submit paperwork and get some sort of seal that says the lights are "approved", then I doubt that any of the suppliers of LED nav lights and strobes meet the "approved" requirement. Actually, Whelen sells LED nav lights and strobes, which I assume are "approved".

However, if you go to Whelen's website their literature implies that an "approved" lighting system projects light from certain locations on the aircraft covering certain areas, at specified intensities. As I read 20-30B of the FARs (Aircraft Position Light and Anticollision Light Installations), I get the impression that the Whelen description is correct. It states that "This circular sets forth the means, but not the only means, of showing compliance with the FAR applicaqble to installed position lights and anticollision lights." So, I interpret this to mean that you do not have to have a piece of paper stating that your lights are "approved", but rather, you have to "comply" or meet the requirements spelled out in the regulations, which happen to be in 20-30B and 20-74, and a few other places, also.

Therefore, my assumption is that if the lights project the correct amount of light in the correct directions, then they meet the letter and the intent of the regulations. Now, as far as nav lights go, this is a fairly easy set of measurements, because the lights are static, and the regulations are very clear. It is not hard using previous generation LED technology to meet the nav light requirements, using 15 LEDs projecting in the correct directions. With current tecnhology, it is hard not to exceed the requirements by a wide margin using as little as 6 LEDs. I have not used Luxons, but they appear to far exceed the requirements, because they project at a very wide angle that easily meets the requirements.

The only requirement that I should make regarding nav lights is that I cannot be sure of the color requirements, since I have not looked that that too closely, but as far as I can tell, the red, green, and white LEDs "appear" to meet these requirements. I think at one time I looked at the color specs and the LED color specs, and they were pretty close, but I have no way to measure this. My assumption is that they meet the intent of the regs, and an inspector would be hard pressed to show that they do not.

Now, regarding the strobe lights, this is a little more iffy. The regs are a little harder to read and interpret, mainly because the strobes are dynamic (i.e, they flash). It is nearly impossible to get an accurate reading using a $50 light meter, and the regs talk about using an integrator light meter, which I do not have access to. So, trying to design something that you can guarantee meets the specs is a little more difficult.

Currently, I have a design using 80 white LEDs that looks pretty good, but is definitely marginal as far as meeting the specs. I do not intend to fly with these, until I can meet the specs 100 percent. I read an article from Jim Weir a few years ago regarding strobe lights, where the strobes put out about 1/2 as many joules as the commercial aviation lights. I think he said something like they did not meet the specs, but they were better than nothing. This bothers me a bit, because my interpretation is that if they do not meet the specs, then we should not be using them. As George said, we should be using equipment that is standardized, so we can all interpret what we see in a standardized manner (i.e., if the strobes are dim, we should be able to interpret that to mean the aircraft is further away).

I just read an article in Contact magazine a few days ago, where a guy put a red light from a truck on the top of his rudder as a strobe light. This more than concerns me, it, actually, scares me a little. I know we have a lot of lattitude, but if builders start doing this kind of stuff, the FAA will remove that lattitude in a hurry. Well, the FAA does not do anything in a hurry, but we could still lose our rights, eventually.


Tracy.

 

[RV6_flyer]

As I read the regs, we are not required to have nav lights or strobes unless we fly at night, or under IFR. If we do fly at night, then our lights must meet the specs.

--- snip ---

I just read an article in Contact magazine a few days ago, where a guy put a red light from a truck on the top of his rudder as a strobe light. This more than concerns me, it, actually, scares me a little. I know we have a lot of lattitude, but if builders start doing this kind of stuff, the FAA will remove that lattitude in a hurry. Well, the FAA does not do anything in a hurry, but we could still lose our rights, eventually.

Tracy.

Tracy:

Sounds like you know what you are doing.

Read Mels posts on DAR. I do the same thing Mel does on my inspections.

I have done inspections on several RVs that have the LED lights. I recommend to the builder that he keep in his records the info furnished by the LED nav light seller, that the lights meet the FAR requirements. If he ever gets RAMP checked by an FAA Inspector, he will have info to SHOW the inspector. Yes you will need to copy and send it to him as you do not keep it in your airplane. He may not like the info you send him but you do have data that they were tested and found to meet FAR 23 requirements for nav light coverage.

Yes it takes time for the FAA to get around to doing things. They have been talking about builder's assistance centers where others build your airplane for you. They know about two RV shops doing this in Texas but are only talking about doing something about it and have taken no action.

 

[gmcjetpilot]

This is getting good

ha ha ha he he he, I am laughing. This is a good Ol dust up.

Gil you are right, you have done some physics.

You can't just LOOK at a light and know much. Even if you have a PhD in physics the world of "Lumen" is a convoluted mix of strange (inconsistent) units inhabited by things call "Nits". Here is a sample:

-Luminous energy Qv lumen second lm?s units are sometimes called Talbots
-Luminous flux F lumen (= cd?sr) lm also called luminous power
-Luminous intensity Iv candela (= lm/sr) cd an SI base unit
-Luminance Lv candela per square metre cd/m2 units are sometimes called nits
-Illuminance Ev lux (= lm/m2) lx Used for light incident on a surface
-Luminous emittance Mv lux (= lm/m2) lx Used for light emitted from a surface
-Luminous efficacy lumen per watt lm/W ratio of luminous flux to radiant flux; max 683.002​

Bed time story: The DAR and the COZY Builder

The jest of the Cozy builders plight is his local DAR, later backed up by the local (Louisville) FSDO decided to say NAV/Strobes must be TSO or PMA units. THAT IS WRONG, at least in my region. Period end of story. This is the opinion of one DAR and one local FSDO, but it's not what my FSDO says.

Yes Part 91 says....., but we don't need to meet part 23 or any other part. OUR AIRCRAFT DO NOT MEET "STANDARD" AIRCRAFT REGULATIONS.

We don't need TSO's and PMA's except may be Transponder and ELT for example. Where am I wrong? We can have experimental lights and the words, "approved anti-collision light system", is being (improperly) interpreted as needing TSO/PMA approval.

The moral of the story and conclusion of the Cozy builder v. DAR is choose your DAR carefully. Apparently once a local a DAR looks at your plane and the FSDO "MAKES A STAND", they are unlikely (read never) to back down, and the home-office is not going to override. Once you start you can't start over and go somewhere else.

This same DAR said his Lycoming said he needed an A&P sign off of all AD's! Please, good idea yes but required? Same with NAV's and Strobes, good to have it meet the same standards as an "approved light system"; I agree with that 100%, but it's not required by LAW. Yes a DAR can make a call; it's their prerogative to exercise their authority, but than we need not patronize that DAR.

If you don't have Whelen and use ANY non-aviation strobe pak or non PMA?TSO light, the DAR and FSDO in Louisville say you can't fly night or IFR. I don't see that in the FAR's

One builders issue does not make a nation-wide precedence or make it right. That is my opinion. I could be wrong and there could be a new "policy paper" on the subject, but I don't think so.

I'm ready to be ridiculed, but I checked this very carefully with my local MIDO. There was no equivocation at my FSDO's, a non-TSO or PMA light system is OK. I also have since doubled checked. If this where true than everyone (with 12 volts systems) has one choice, incandescent Whelen lights.




With all that said, this is why I DID NOT go with LED's. Just the potential hassle. Also I did not know if they would meet the standard, which was my requirement, and I did not want to varify it myself.

I went with Aeroflash which looks certified. Fact is they are not PMA or STC'ed either, except for the fact they look just like Whelen, I am basically in the same boat as this Cozy builder or anyone with the weirdest homemade lights ever, they are not PMA'ed or STC'ed per Louisville FSDO. Ridiculous just like getting a A&P to sign my engines AD's off.

How many homebuilts have been approved with LED's? Countless. This just shows you how the FAA and no offense, some DAR's, get a reputation. Again choose your DAR carefully and let's ID the ones that work on opinion and not the regulations.

The FAA publishes policy papers for Inspectors and DAR's we don't see. I'm sure there is some info out there. The deal is educate yourself and have it in your back pocket. If you get a show down you need to stop it right there. Once he (the DAR) writes it up, making it an issue, you are going down a bad road, where reverse gear doesn't work and its not wide enough for 180 turns.

I don't know if it's ego at that point, but how many times does the FAA say, Oh we are wrong, we are sorry? May be it would affect their career to be wrong? May be there is no FAA paper work to say you where wrong and reverse your ruling? I guess you can go to court against the FAA, but that is extreme and probably a looser. The Cozy builder just replace the lights with $900 of Whelen.




To be fair to the FAA, we have a lot of freedoms and they usually do a fair job, including ruling on lights, so lets not put really weird lights on and push the issue.

I (the builder) write the log book endorsement that it meets for night flight or IFR flight, not the FAA or DAR. However the FAA/FSDO and DAR have the power to put a kabosh right or wrong on your game.

If you are worried buy a Whelen. I personally think you should meet the specs for "approved" light systems, but you determine that. For the record I also don't think some of the commercial LED based systems are very good or should be used, in my opinion. The one in question by the Cozy builder was the GS-air unit. I see some issues with it, but again, you have to test to prove it yea or nay. All this is why I went with a Whelen look a like, but it is not PMA/STC either.

Let the games begin. It does not matter what anyone says on the list, all respect to DAR Mel, but what counts is the DAR or FAA Inspector who actually checks your plane off. If worried, talk to your local DAR or FSDO before buying or making your own NAV/Strobe lights. Here is the news, the FAA and DAR's are inconsistent in interpreting the rules. Really, hard to believe; don't forget where you heard it first.

(NOTE: reading the email post it is not clear if he ever resolved the GS-air issue but he may have? I don't know may be GS-air changed the design.)

 

[the_other_dougreeves]

LEDs + 12V = Bad? Silly!

When I asked Whelen about their plans for an LED lighting system they got downright defensive and declared that the technology for 12v LEDs wasn't capable of meeting the FARs. They claimed no one could use 12v LEDs and comply with the FARs.

What? 12V won't work? Hmm.....

The most common high-output LED right now is the Luxeon, which is available as a Lux I (1W), Lux V (5W, essentially several Lux Is on a single die) and Lux III (3W). The Lux III is the best of these, and it has a much better lifespan than the V while giving up little in terms of brightness (60-100 lumens). If a normal current of 1000 mA is applied, the "forward voltage" of the Lux III will be about 3.5 to 4V, with 80 lumens from the white, green and red versions.

They are normally driven by constant-current power supplies called "drivers". There are many good drivers out there, most of which require a higher input voltage than output voltage. So, this means that a 14V system and a single 1000 mA driver could drive up to 3 Lux IIIs.

My guess is that 3 Lux IIIs are more than enough for a nav light; 2 should be enough for the red and green with the 3 on the white - less than 3A total draw.

Ok, now what about strobes? There are certainly drivers that will "strobe" your LEDs, but I'm not sure they'd meet the brightness requirement. A quick conversion says that in order to meet the 400 candela requirement for strobes with a 180 deg visibility, you'd need 2,500 lumens. That's 30 Lux IIIs! Best to stay with traditional strobes at the moment.

EAA Chapter 724 has a good discussion on the use of Luxeons as homebrew nav lights. There's also a very interesting looking paper on the subject as well (haven't read it - $15 for the article). LED Supply is a good source for LEDs and drivers.

 

[gmcjetpilot]

Very interesting

What? 12V won't work? Hmm.....

The most common high-output LED right now is the Luxeon, which is available as a Lux I (1W), Lux V (5W, essentially several Lux Is on a single die) and Lux III (3W). The Lux III is the best of these, and it has a much better lifespan than the V while giving up little in terms of brightness (60-100 lumens). If a normal current of 1000 mA is applied, the "forward voltage" of the Lux III will be about 3.5 to 4V, with 80 lumens from the white, green and red versions

Hummm interesting, wounder why Whelen does not make a 12 volt version?


I noticed now has two new LED NAV lights. One is a new standard looking replacement to the NAV/Strobe combo, and the other is a new LED tail light.
It looks like they use about 6 or 7 LEDs to get the job done.

I wounder if Whelen does not make 12 volt LED lights because they don't want to stop sales of there existing incandescent line?

The Lux III's are pretty awesome LED's. Many of the aftermarket light systems don't use them however, from what I can tell. I still don't get the need for 28 volts to drive them as Whelen implied. As you point out they work on 3.5-4 volts.

 

[thallock]

Actually, LEDSupply is not a very good source of LEDs. They will cost you about $1 per LED, plus shipping. Two better sources that I have used are Best Hong Kong and Light of Victory on EBay:

http://www.besthongkong.com/

and

http://stores.ebay.com/Light-of-Victory-Led-Store-lvehk

Even with the shipping they will run about $.15 for 10,000mcd or $.35 for 130,000mcd (yes 130 candella are available).

One other thing, regarding the current draw of LEDs in the article, is that all of the high intensity LEDs current available draw approximately 20ma for their nominal specified output. The article talks about 350ma, which are more in line for Luxons than LEDs. Otherwise, it is a good article.

Tracy.

 

[Mel]

George,
One minor correction. AeroFlash strobes are PMAd. They are used on Grumman AA series, Rockwell, and many Cessnas. Now Aeroflash does make some lower powered non-PMAd lighting systems. But their standard systems are PMAd.

 

[the_other_dougreeves]

Actually, LEDSupply is not a very good source of LEDs. They will cost you about $1 per LED, plus shipping.

Sorry - I should have noted that they're a good source for Luxeons, not as much for small LEDs. Luxeon IIIs stars are running about $6 - 7 each everywhere I've looked.

Two better sources ... Even with the shipping they will run about $.15 for 10,000mcd or $.35 for 130,000mcd (yes 130 candella are available).

While these 5mm and 10mm LEDs are all great intensity, they are very narrow beams (12 deg). The standard Lux III is a lambertian 140 deg pattern. The true measure of total light output is flux, measured in lumens. My guess is that you would need many, many of these LEDs to get the 80 lumen output of a single Lux III. If you really wanted to shape the pattern and couldn't do that with a reflector or optics (e.g., line source inside the cockpit), then many smaller LEDs would be the way to go.

 

[gmcjetpilot]

Thanks, some products are

George,
One minor correction. AeroFlash strobes are PMAd. They are used on Grumman AA series, Rockwell, and many Cessnas. Now Aeroflash does make some lower powered non-PMAd lighting systems. But their standard systems are PMAd.

I hear you, thanks for keeping me straight, absolutly they have PMA's stuff, but not all of their products are PMA's. The "Experimental or Home-Built Aircraft" lights are not PMA's. The strobe pwr is down a little from the current reg's but OK to use them on experimentals.

 

[az_gila]

Watch the maximum angle

While these 5mm and 10mm LEDs are all great intensity, they are very narrow beams (12 deg). The standard Lux III is a lambertian 140 deg pattern. The true measure of total light output is flux, measured in lumens.

the other Doug.....

Remember the FAA specification have a maximum intensity (candela) for the overlap angles that are greater than the basic 110 degrees for the red/green nav. lights. nice and bright (physics - brightness = luminous intensity = candela) normal to the LED mounting might exceed the fringe intensity specification. You might need some careful lens work or baffles to cover this area. Any reflective (even white) areas in the mount could alter the light distribution obtained from the system -- and yes, it really is a system when it is installed in your wingtip. It all needs to be accounted for - and the easiest way is for a meaurement in the dark with a calibrated photometer at different angles to the light. This would quickly give you an intensity distribution in both the horizontal and vertical planes, and would give a definite yes/no to the FAA specifications.

gil in Tucson .... past member of the Illuminating Engineers....

 

[the_other_dougreeves]

the other Doug.....

Remember the FAA specification have a maximum intensity (candela) for the overlap angles that are greater than the basic 110 degrees for the red/green nav. lights. ...
-- and yes, it really is a system when it is installed in your wingtip.

Yes, agreed. More light is not always better - it needs to be controlled. Proper reflectors, optics or baffles are necessary. However, this should be fairly simple to do.

 

[az_gila]

Agreed.... measure it...

Yes, agreed. More light is not always better - it needs to be controlled. Proper reflectors, optics or baffles are necessary. However, this should be fairly simple to do.

Agreed, as long as you have the equipment to measure the light intensity and actually use it.

I haven't heard any of the LED suppliers specifically say they did actual measurements on an installed system with calibrated equipment....

gil in Tucson