What I have learned about LED landing lights

[PTK]

Recently my GE landing light bulb burned out after many years of service. I wanted to replace it with an LED and have been researching them for some time. I learned some things in the process and wanted to share.

Because led bulbs are not regulated by the FAA, manufacturers want to make their bulbs appear better than the rest on paper and things become very confusing very fast. A good example is all the talk about lumens and candelas. The latter tells us how bright the light source is in a certain direction which indicates how far away we can be from an object and still be able to illuminate it. It’s the light intensity in a single direction from the light source. When sitting behind a light and we want to see straight ahead into the distance, as is the case with a landing light, the candela is the most important metric. Lumen is total light output in any direction. So if we care about direction, as in straight ahead with a landing light, we want high candela values which are sustained over time. And here is where it becomes interesting. Some manufacturers play tricks with this. They can drive the led very hard in order to get high candela values which they proudly publish in their advertisements. What they don’t tell us is that led lights get hot especially when driven hard and must be protected. They call this thermal management. This is very important in my application because my landing light sits inside a cavity in the lower cowl. Mostly all have heat sinks to dissipate heat away from the light. Another way they manage heat is to throttle the led back and reduce power. In doing so the candela value drops very precipitously. There’s one manufacturer that I found who advertises a very high candela value. What they will not tell us is that this value decreases by a whopping 75% after about 30 minutes of operating the light! This would be very bad landing light. The data is obtained by independent lab testing. One such lab is Light Laboratory, Inc. in California. The manufacturers have this data and should provide it if a customer asks for it. This particular manufacturer would not provide it saying it’s proprietary information. I now know why!

So when selecting an led landing light it is very important to bypass the flashy ads and reliance on a sales pitch. Rely instead on independent data. It exists and manufacturers have it. Ask for it! Consider how it will be operated and the conditions in which it lives. Does it receive air flow to help cool it or is it enclosed? Does it have superior thermal management by design or does it depend on throttle back? It´s very important to ask the manufacturer for this data and select one that sustains the candela value over time. This means the led´s are not overdriven and it has superior thermal management built in to its design. If they refuse to provide this independent data their light is probably not worth the hundreds of $$ they’re asking! 

The landing lights with the best data that I found are Whelen lights. Their data is so good that they publish it in their brochures.

Edited May 23, 2019 by PTK

[Steve W]

I've installed Wing Mounted LED landing and taxi lights in my M20J and in static tests they start thermal throttling very quickly. I'm still missing the spinny bit on the front of the plane but the manufacturer says they should do much better in actual engine-running conditions. I'm going to try and figure out how to measure the current once I have an engine and a repaired plane and  see how they do in actual conditions and will then share the results.

The other way to improve candela is to make the beam narrower, which is why I get annoyed when beam diagrams or at least beam dimensions aren't posted. 1 trillion candlepower..... 0.01 degree beam is pretty useless... but really bright.

 

[hypertech]

Side by side, the whelen lights don't hold up.  They make a nice LED strobe, but their landing lights are behind the times.  Even the newer version.  I went with the Aeroleds and am very happy.  If you have a ton of cash to burn and want to really light it up, they have a high output version too.

Not sure what spec you are looking at to make you think Whelen is better.  For the PAR36, Whelen claims 60,000 candlepower, which is something like 58k candela.  Aeroleds is 65k candela for the regular version and 150k for the 4596 version.  

[PTK]

14 minutes ago, hypertech said:

Side by side, the whelen lights don't hold up.  They make a nice LED strobe, but their landing lights are behind the times.  Even the newer version.  I went with the Aeroleds and am very happy.  If you have a ton of cash to burn and want to really light it up, they have a high output version too.

Not sure what spec you are looking at to make you think Whelen is better.  For the PAR36, Whelen claims 60,000 candlepower, which is something like 58k candela.  Aeroleds is 65k candela for the regular version and 150k for the 4596 version.  

The point of my post was to share what I have learned. Independent data exists. Manufacturers have it. Ask aeroleds to provide you the independent lab data of candelas over time. Assuming you leave your landing light on for more than a minute, candelas over time is the most important metric. Throwing out numbers with no basis is meaningless.  

Edited May 23, 2019 by PTK

[jaylw314]

39 minutes ago, PTK said:

The point of my post was to share what I have learned. Independent data exists. Manufacturers have it. Ask aeroleds to provide you the independent lab data of candelas over time. Assuming you leave your landing light on for more than a minute, candelas over time is the most important metric. Throwing out numbers with no basis is meaningless.  

Who is the independent lab?  There name isn't Theranos, is it? 

[MIm20c]

Not familiar with the lab results but my eyes still haven’t recovered from staring into a 4596 bulb two years ago at OSH. 

[hypertech]

 

[N201MKTurbo]

I haven't landed with the landing light for about 30 years. My old F would burn out the landing light on landing, so I started turning it off before I touched down, and it never burned out again. I guess it has something to do with jarring the hot filament.

Anyway, I did it so much that I found it very weird to land with the landing light on. The tower sometimes freaked out when I turned it off, but I would tell them it was OK. I just used it to taxiing. Some airports don't have taxiway lights and it can be hard to taxi without a light. My breaker would blow after about 5 minuets and it was getting very annoying, so I went out and bought a Whelen light. I leave it on all the time now and it never blows the breaker! It makes a great taxi light! I still turn it off on final. I will learn to land with a landing light one of these days.

[L. Trotter]

What I learned about LED lights......... 

I had an interesting experience with my new Aero-Lites LED PAR 36 landing/taxi lights.They're mounted in the wing of my Acclaim. 

This past week I was traveling from Provo, Utah to Wausau, Wisconsin. I encountered icing in route and made good use of my TKS system (what a nice addition). For those not familiar with TKS, the entire wing leading edge is protected except the lenses of the landing lights. In the past, with my incandescent GE bulbs, I could turn the lights on and the heat produced would melt the ice on the lenses. The outside temperature just changed the length of time required, maybe 15-30 min if real cold (> -10C). With the LED lights on for >1hr @ -5C the 1/8" layer of ice did not even budge. Granted this is far from scientific, but a real world observation...A good thing or not, you decide. As for me, the pros of less heat out-weight the cons.

By the way, I love these lights. Even after > 1hr use, they are extremely bright and far better at illuminating the run way/taxi ways than the original GE bulbs.

[M016576]

My current J... which has the Missile Mod (a K cowling that’s been modified, and has two par36 landing lights in it), has LED landing lights.  The plexiglass cover has a bunch of small holes drilled near the bottom. 

I thought they might be drain holes... but after reading your post @PTK I’m thinking perhaps they are for cooling?  The backs of the two landing lights do have some pretty robust looking heat sinks attached.  Not sure of the manufacturer.  I’ll take some pictures of the plexiglass cover if anyone’s interested.

[carusoam]

Expect the holes in the cover are for cooling air.... acrylic starts to soften right around the temp for boiling water...

Best regards,

-a-

[ArtVandelay]

My current J... which has the Missile Mod (a K cowling that’s been modified, and has two par36 landing lights in it), has LED landing lights.  The plexiglass cover has a bunch of small holes drilled near the bottom. 
I thought they might be drain holes... but after reading your post [mention=7035]PTK[/mention] I’m thinking perhaps they are for cooling?  The backs of the two landing lights do have some pretty robust looking heat sinks attached.  Not sure of the manufacturer.  I’ll take some pictures of the plexiglass cover if anyone’s interested.

I don’t have any holes in mine, but mine were installed by Mooney Mart. I like to see a picture of yours. I’ve seen a number of installations, the factory I think doesn’t have the frame bracket.


Tom

[Yetti]

here is the other interesting thing.  When people pull out their incandescent and put an LED in with the accompanying  "look how much brighter the LED is" pictures.  There is a reason for this.   Temperature of the light waves.   The CCD (charge couple device) in your camera "see" the light temperature of an LED much better than an incandescent.   To test this point a TV remote up to your cell phone camera and use the buttons.  Same with your eyes.   They see some temperatures better than others.

[PTK]

13 hours ago, hypertech said:

 

This is a good review of lights and what’s currently available. However imo it misses the single most important point: how do these lights handle thermal management. To what extent do they rely on throttle back. How bright they appear when initially turned on is useless and very subjective. They are all bright when initially turned on! Here is the data on the aeroleds 2130LX. Initially it comes in at 190000 candela but look how it degrades even after just 5 or 10 min. It’s a light. But it definitely does not satisfy the requirements for a landing light.

The led landing light with best data that I have seen is the illumivation lazr. This is by the former Lopresti which now is Whelen. If I go the led route this  would be my choice. Whelen bought Lopresti and dropped the price also. 

https://www.illumi-vation.com/product-page/mooney-m20-c-d-e-f-g-j-led-landing-light

Edited May 24, 2019 by PTK

[larrynimmo]

Let me give you the Larry Nimmo test data...I have a J..with a single large light in the cowling....I had the Whelen and it was brightest, but beam was so narrow that it was darn useless as a taxi light.

i installed the sun setter and while not as bright, it gives the best of both worlds for my plane...there is no going back.

the $300 Whelen bulb has 25 hours on it and I will sell it for $150...the same price I paid for the sunsettersun setter

[elimansour]

I looked at the Aero-Lites website and was about to buy the lights when I noticed that there awe not PMA approved and clearly noted as not for use on certificated products and for experimental use only...bummer.  

[kris_adams]

great discussion on Beechtalk about whether an STC or PMA is required.  Per the article the GE 4509 carries neither STC nor PMA and has been used for decades.  Lots of good points.  Clearly this isn't a major alteration so an STC isn't required.  Sounds like most people feel it falls into the gray area under part 43 and you or your mechanic has to make the call.  I'm in the no big deal camp but the regs get confusing and contradictory very quickly to me.

https://www.beechtalk.com/forums/viewtopic.php?f=7&t=51177&hilit=landing+lights+require+pma

-K

[hypertech]

2 hours ago, PTK said:

This is a good review of lights and what’s currently available. However imo it misses the single most important point: how do these lights handle thermal management. To what extent do they rely on throttle back. How bright they appear when initially turned on is useless and very subjective. They are all bright when initially turned on! Here is the data on the aeroleds 2130LX. Initially it comes in at 190000 candela but look how it degrades even after just 5 or 10 min. It’s a light. But it definitely does not satisfy the requirements for a landing light.

The led landing light with best data that I have seen is the illumivation lazr. This is by the former Lopresti which now is Whelen. If I go the led route this  would be my choice. Whelen bought Lopresti and dropped the price also. 

https://www.illumi-vation.com/product-page/mooney-m20-c-d-e-f-g-j-led-landing-light

Did they point a 200 mph fan at it when they did this test?  If not, its unrealistic and useless data :p

I have a different model of the AeroLED light, but still that test probably also does not take into account the spread.  The AeroLEDs are are way better than stock - all of them probably are - and certainly satisfy the requirements for a landing light.

I think that lazr light is in the video too.  The video is much better evidence of how the light performs than a spreadsheet.

[jaylw314]

11 hours ago, M016576 said:

My current J... which has the Missile Mod (a K cowling that’s been modified, and has two par36 landing lights in it), has LED landing lights.  The plexiglass cover has a bunch of small holes drilled near the bottom. 

I thought they might be drain holes... but after reading your post @PTK I’m thinking perhaps they are for cooling?  The backs of the two landing lights do have some pretty robust looking heat sinks attached.  Not sure of the manufacturer.  I’ll take some pictures of the plexiglass cover if anyone’s interested.

I think the holes are more for preventing condensation.  I imagine the light is enough to raise the temp 20-30 degrees, but the normal airflow should keep the acrylic well below anything damaging.  I'm reminded of acrylic aquariums, where people have two 500W halogen lamps blasting down through the top acrylic, and the acrylic above the waterline gets warm but not hot enough to melt.

[carusoam]

Halogen lamp temps.... (for Jay)

They get incredibly hot.... 400°F and hotter depending on wattage... and airflow...

https://en.m.wikipedia.org/wiki/Halogen_lamp

 

leaving the recog lights on (in the Long Body) while taxiing on the ground, melts the formed acrylic lenses mounted in front of it...

Fun reminder to use the darn check list after landing... you don’t get much time to get them turned off...

My medium quality fish tank has glass between the hood light and the water...

PP thoughts only, not a mechanic...

Best regards,

-a-

[jaylw314]

1 hour ago, elimansour said:

I looked at the Aero-Lites website and was about to buy the lights when I noticed that there awe not PMA approved and clearly noted as not for use on certificated products and for experimental use only...bummer.  

When I asked my IA if he would file a 337 for installing my old Whelen LED, he looked at me like I was growing a third head.  I had two IA's tell me to just put the damn thing in and write the log entry myself.

FWIW, PMA has no bearing on whether you can install it--it only authorizes a manufacturer to sell it as a replacement for certificated aircraft.  Once you have it in your hands, it still may or may not be legal to install.  AFAIK, replacing an item that has a TSO requires the new item to meet the same TSO, which is true for position lights and anticollision lights.  However, there's no TSO for landing lights, so the debate has been whether it's legal to do as a minor alteration or preventative maintenance.

I opted to install it under preventative maintenance (I've since switched to the Aero-Lights Sunsetter), and I think the vast majority of LED landing light installations out there are done this way.  I keep an incandescent bulb around in case some inspector ever has a problem with it.

[jaylw314]

2 minutes ago, carusoam said:

leaving the position lights on (in the Long Body) while taxiing on the ground, melts the formed acrylic lenses mounted in front of it...

Really?  I didn't think there were any halogen position lights?

I know the recognition light bulbs melt the wingtip lenses on the later J models, but they are super close to the lens and have a focusing mirror.  Landing lights are meant to spread over a wider arc (and the multiple LED's diffuses the light further)...

[carusoam]

Oops...

Wrong word.   Recog lights... (Thanks Jay!)

I don’t know what type of light it is.....

But I do know what temp softens acrylic....

 

When it comes to lights...

It is important for them to work.  That is easy to test.

It is often the other things that come with the new technology that can cause something to not be useable...

Some technologies can bleed electronic noise or radio frequencies that can interfere with our more sensitive nav equipment...

 

even some certified older equipment can be can be hazardous to newer equipment...  ie my Narco nav/com would prevent my portable GPS from navigating.  The Narco bled so much radiation on some nav frequencies, it blocked the operation of the GPS...

 

Hard to see what is going to get in the way... when it comes to new technology...  

It really helps to have the MS community give pireps on things that work for them...  I’m no longer a fan of being first... 

Best regards,

-a-

[PTK]

1 hour ago, hypertech said:

Did they point a 200 mph fan at it when they did this test?  If not, its unrealistic and useless data

Frankly, I think the data is very realistic. I don't know about yours but as I said my landing light lives in a closed cavity in the lower cowI.  I don't want it relying on throttle back reducing its output so it doesn't overheat. I want it to be properly designed to dissipate the heat while retaining its candelas.   

Edited May 24, 2019 by PTK

[jaylw314]

4 hours ago, PTK said:

This is a good review of lights and what’s currently available. However imo it misses the single most important point: how do these lights handle thermal management. To what extent do they rely on throttle back. How bright they appear when initially turned on is useless and very subjective. They are all bright when initially turned on! Here is the data on the aeroleds 2130LX. Initially it comes in at 190000 candela but look how it degrades even after just 5 or 10 min. It’s a light. But it definitely does not satisfy the requirements for a landing light.

 

The led landing light with best data that I have seen is the illumivation lazr. This is by the former Lopresti which now is Whelen. If I go the led route this  would be my choice. Whelen bought Lopresti and dropped the price also. 

https://www.illumi-vation.com/product-page/mooney-m20-c-d-e-f-g-j-led-landing-light

I have to say, the lab test doesn't pass my smell test since I have seen neither the Whelen nor Aero-Lights decrease in brightness perceptually or functionally over the course of a flight.   It's hard to imagine not noticing a 70% reduction in illumination--that should have an impact on pilot performance.  It's not like I'm "wowed" by the runway illumination on takeoff, and then saying "waitaminute" after landing, nor am I having more difficulty taxiing after vs before the flight. 

To pass the smell test, the reduction would have to be less than, say 20% to escape detection, and then that also calls into question whether the test results produce any meaningful difference in cost-effectiveness.  Now, if someone produced a study showing that pilots cannot perceive a 70% reduction in illumination, nor does it affect their piloting performance (which I concede is at least a possibility), the LED test may hold some more weight, but that wouldn't exactly change the cost effectiveness, would it?

Edited May 24, 2019 by jaylw314