LED Landing & Taxi Lights STC

[DutchessFlier]

Just an FYI, in case you are interested....Whelen has posted the STC which was finally granted approving use of LED lighting for Par-36 replacements in certificated aircraft. Whelen's LED fixtures are called 'Parmetheus' and in my opinion, FWIW, they have done an excellent job so far.

I have installed them in my plane. They do just drop right into the plane and use the same wiring, hardware and attachments that the incandescent bulbs used. Not cheap, but with a 3 year warranty, an expected 5K hours of life, and a current draw of .6amps in a 28volt system, I basically leave them on virtually all the time. They also run cool to the touch.

No, I am not an advertisement for LED's. To me, anything I can do that improves my visibility aloft, and decreases the strain on my electrical system, is worth the effort.

 

[John Collins]

I also installed LED landing and taxi lights on my airplane. The primary motivation was the reduced current draw. On my 14 volt Bonanza, the GE 4313 light bulbs called for in the parts manual for landing and taxi draw over 19 amps each, so at low RPM's it wasn't practical to use them at the same time without a severe brown out. The LED replacements draw 1.2 amps each.

I don't believe that a steady on landing light helps with increased visibility and recognition during the day time in VFR conditions, but it definitely helps during dusk, night time, and low visibility conditions. I do think that a flashing landing light makes a difference in day VFR collision avoidance recognition. Regardless, I like my new LED landing lights.

 

[PilotAlan]

Spruce is still selling the Whelen LED for $239, saying "STC Pending". Whelen retail is $475
I ordered one from them yesterday, I am sure the price will be bouncing up after they update the site with the STC. If you're thinking about getting one, now's probably the time.

For me it's not about bulbs, but amps. My Cherokee has the 37 amp electrical system. A 4509 pulls 7-8 amps, or 20-25% of my total alternator output, vs the LED at 1.2 amps.
Next is to replace nav lights with LEDs, and gain another 3-4 amps of draw, for a total of 10 amps saves (or 1/3rd of my alternator output).
That's a whole lot cheaper than upgrading my electrical wiring to the later 50amp capacity.

 

[DutchessFlier]

John: Agreed about daytime VFR...but around here especially in the summer, flight visibilities generally stink due to haze and the everpresent inversions.

Alan: Yep: Besides longevity, the current draw is a huge gain for the electrical system. You should not have to pay Whelen list price for them ever. I bought them through Spruce at, if I recall correctly, $249/each. The installation was as simple as changing out the bulb.

 

[PilotAlan]

I bought them through Spruce at, if I recall correctly, $249/each.

Yes, but my point was that Spruce hasn't updated their site with the STC. I expect prices to be going up VERY shortly. Up until now it's been non-certified.
So if someone wants one, right now is probably the time to order.

 

[azure]

This is very timely for me since 8JT has a burned-out taxi light. So I ordered the Whelen LED pair from Aircraft Spruce, only to find out in my confirmation email that the 14-volt taxi light is on backorder and isn't expected to be back in stock until Oct 25.

I don't mind waiting as long as they honor the current price, but just FYI that some of these are not in stock.

It looks like the original GE-4509 is only $8.95 from Spruce, so I'll probably order one of those for the meantime.

 

[el con]

On a slightly different subject, I put a Whelen LED tail beacon on my Cherokee a few years ago. Replaced the old rotating beacon. Everyone knows my plane coming into our Airport at night as it is almost like a red pulsing laser. Current draw dropped dramatically and no more listening to the old R. beacon grinding around over the headset. No power supply needed, reduction of weight ,all +'s ,only thing ,Led's do degrade in brightness over time. It will be interesting how the landing lights hold up.
I will probably replace the landing light and the position lights in the near future with LED.
LED's are pretty awesome.

 

[weirdjim]

only thing ,Led's do degrade in brightness over time.

Time as measured in tens of thousands of hours, as I recall. And as a function of being run inside of their ratings.

 

[slowjoe]

I put mine in my 172 Thursday and flew that night. What a difference! Not neccessarily more light, but the color temp of the light is much better and allows you to see much more detail.

And the fact that it draws almost no power is really nice too.

 

[gismo]

Time as measured in tens of thousands of hours, as I recall. And as a function of being run inside of their ratings.

LED life is generally stated in terms of the operating time at max rated current before the output decreases to half of what's spec'd for the minimum initial output. And if you decrease the current by something like 10% the life about doubles IIRC.

 

[weirdjim]

LED life is generally stated in terms of the operating time at max rated current before the output decreases to half of what's spec'd for the minimum initial output. And if you decrease the current by something like 10% the life about doubles IIRC.

Care to quote a source? I generally teach my college classes that at rated current there is not a known wearout mechanism. Can you give a wearout mechanism?

Jim

 

[Clark1961]

Care to quote a source? I generally teach my college classes that at rated current there is not a known wearout mechanism. Can you give a wearout mechanism?

Another less than useful academic position which ignores fact and offers only diversion.

Maybe you'll accept Philips expertise? http://www.philipslumileds.com/uploads/165/WP12-pdf

 

[Ted]

The LED stuff is nifty. Personally, I'd really like to get wingtip strobes installed in the planes I fly. Aside from making the plane look cooler, it certainly can only improve visibility of the plane.

Whether or not it will really do anything in daytime VFR, I couldn't tell you.

 

[gismo]

Care to quote a source? I generally teach my college classes that at rated current there is not a known wearout mechanism. Can you give a wearout mechanism?

Jim

I've read that the wearout mechanism that leads to decreasing output over time is the creation of lattice defects in the semiconductor crystal at or near the junction region and that this process is accelerated by elevated temperatures and junction current. I've also read that the life expectancy of high power LEDs varies considerably with several design factors along with junction temperature and forward current. Also it appears that there is an evolving standard for LED life (L70) which is supposed to represent the average operating time at 25C and max rated current which results in a decrease of 30% in output. I don't know what "standard" was used to generate the expected lifetimes of the aviation products available today but I can say it's very unlikely any of those numbers are based on direct testing. IOW YRMV.

 

[weirdjim]

Another less than useful academic position which ignores fact and offers only diversion.

Maybe you'll accept Philips expertise? http://www.philipslumileds.com/uploads/165/WP12-pdf

Of course I accept Philips expertise. Just like I accept expertise of anybody who is actually making devices. You did notice, I assume, that a Philips power device being run at rated current did not degrade 10% in 6000 hours? And that 30% degradation is the point at which the human eye can detect a difference in light output? And that it is all a matter of keeping the junction as close to ambient as possible?

We had the same bathtub curve in bipolar power devices for a few years also, but with improved processes that bathtub has become a swimming pool.

Perhaps I should have stated it that small power devices have a very long (infinity is a super long) lifetime, and that power devices have lifetimes exceeding 99% of the general aviation fleet hours.

Sorry to have been so flip as to say that there is no known wearout mechanism. Of course there is, and 95% of it is up to the mechanical designer to get the heat out of the device.

Jim

 

[Clark1961]

Of course I accept Philips expertise. Just like I accept expertise of anybody who is actually making devices. You did notice, I assume, that a Philips power device being run at rated current did not degrade 10% in 6000 hours? And that 30% degradation is the point at which the human eye can detect a difference in light output? And that it is all a matter of keeping the junction as close to ambient as possible?

We had the same bathtub curve in bipolar power devices for a few years also, but with improved processes that bathtub has become a swimming pool.

Perhaps I should have stated it that small power devices have a very long (infinity is a super long) lifetime, and that power devices have lifetimes exceeding 99% of the general aviation fleet hours.

Sorry to have been so flip as to say that there is no known wearout mechanism. Of course there is, and 95% of it is up to the mechanical designer to get the heat out of the device.

Jim

I'm not likely to accept your apology. Perhaps if you admit the generally accepted degradation of LED output with time and state that you will change your lectures then it will be acceptable. You offer no indication that you will stop misleading students. How sad.

 

[el con]

Sorry I started the wear out part of this.
My only concern is this: even if they wear out from the 50% degradation and takes them from 20,000hrs. down to 10,000hrs ,and I fly only 60-80 hrs a year. I'm 59, I'm not ever going to get the full use out of them in the next 125 years

 

[gismo]

Sorry I started the wear out part of this.
My only concern is this: even if they wear out from the 50% degradation and takes them from 20,000hrs. down to 10,000hrs ,and I fly only 60-80 hrs a year. I'm 59, I'm not ever going to get the full use out of them in the next 125 years

If you want to get "full use" just leave them on in the hangar!

 

[DutchessFlier]

Sheesh Folks:

Can anyone say Thread Creep?

C'mon and take the technical battles over LED lifespan to another place

 

[azure]

My Whelen LED Landing Light arrived from Aircraft Spruce yesterday, along with the sealed beam taxi light to tide me over until they stock up again on the LED taxi lights. I'm looking forward to seeing how it works when my mechanic installs it at my upcoming oil change (I've assisted another owner replacing a Cardinal landing light and it's more work than I'm interested in tackling right now -- you really have to drop the lower cowl or you will end up with lots of scrapes and cuts on your arms).

But now I've another mystery. My PulseLite system stopped working at the same time as the taxi light went out. I don't have the circuit diagram for the PulseLite but I can't imagine any way they could have wired it so that with one bulb open, the system couldn't flash the other light. So now I'm wondering if the problem is the taxi light at all, and not something failed in the PulseLite system. Hmmm.

 

[alaskaflyer]

My Whelen LED Landing Light arrived from Aircraft Spruce yesterday, along with the sealed beam taxi light to tide me over until they stock up again on the LED taxi lights. I'm looking forward to seeing how it works when my mechanic installs it at my upcoming oil change (I've assisted another owner replacing a Cardinal landing light and it's more work than I'm interested in tackling right now -- you really have to drop the lower cowl or you will end up with lots of scrapes and cuts on your arms).

Did your purchase come with the STC paperwork?

 

[DutchessFlier]

Did your purchase come with the STC paperwork?

You can go to the Whelen website and download the STC and any associated installation and airworthiness info from there.

Moose

 

[Jeff Argersinger]

Spruce is still selling the Whelen LED for $239, saying "STC Pending". Whelen retail is $475
I ordered one from them yesterday, I am sure the price will be bouncing up after they update the site with the STC. If you're thinking about getting one, now's probably the time.

For me it's not about bulbs, but amps. My Cherokee has the 37 amp electrical system. A 4509 pulls 7-8 amps, or 20-25% of my total alternator output, vs the LED at 1.2 amps.
Next is to replace nav lights with LEDs, and gain another 3-4 amps of draw, for a total of 10 amps saves (or 1/3rd of my alternator output).
That's a whole lot cheaper than upgrading my electrical wiring to the later 50amp capacity.

Hi Alan,
Jeff Argersinger from Whelen here. Just a quick note to let you know that there are no plans to raise the pricing of the Parmetheus LED lamps now that the STC has been awarded. The correct LIST price is $325. I have contacted Aircraft Spruce regarding the updates needed on their web site. If anyone has any further questions, I will be happy to answer to the best of my ability. Thanks.

Jeff Argersinger
jargersi@whelen.com
Whelen

 

[Jeff Argersinger]

On a slightly different subject, I put a Whelen LED tail beacon on my Cherokee a few years ago. Replaced the old rotating beacon. Everyone knows my plane coming into our Airport at night as it is almost like a red pulsing laser. Current draw dropped dramatically and no more listening to the old R. beacon grinding around over the headset. No power supply needed, reduction of weight ,all +'s ,only thing ,Led's do degrade in brightness over time. It will be interesting how the landing lights hold up.
I will probably replace the landing light and the position lights in the near future with LED.
LED's are pretty awesome.

Yes you are correct in degredation over time. There are several valid points regarding the life of the LED's within this thread.
All of the Whelen designs take into account thermal management of the junction temperature of the LED's as a top priority. This substantiates our conservative claims of 10,000 hours of consistent light output without degradation. The designs also use fixed (linear not switched) current sources to maintain steady and consistent light output with any fluctuations in voltage/current.
Regards.
Jeff Argersinger
Whelen

 

[SCCutler]

Jeff:

1. Thanks for your input;

2. Congrats on the STC - looks like a fine product, and may well justify my delay in buying an HID setup;

3. Welcome to PoA - don't be a stranger!

 

[alaskaflyer]

Yes you are correct in degredation over time. There are several valid points regarding the life of the LED's within this thread.
All of the Whelen designs take into account thermal management of the junction temperature of the LED's as a top priority. This substantiates our conservative claims of 10,000 hours of consistent light output without degradation. The designs also use fixed (linear not switched) current sources to maintain steady and consistent light output with any fluctuations in voltage/current.
Regards.
Jeff Argersinger
Whelen

I wonder how their performance is with pulse lights/wigwags or similar systems, and if that constant cycling of power would affect longevity?

 

[gismo]

I wonder how their performance is with pulse lights/wigwags or similar systems, and if that constant cycling of power would affect longevity?

Constant cycling shouldn't be an issue as long as the LED's themselves have good wire bonding, something the manufacturers have gotten pretty good at these days. Heck, it doesn't even bother the incandescents.

 

[Jeff Argersinger]

Constant cycling shouldn't be an issue as long as the LED's themselves have good wire bonding, something the manufacturers have gotten pretty good at these days. Heck, it doesn't even bother the incandescents.

Flashing has no affect on the life of the leds. The beauty of the LED is when flashed, it is essentially instantaneously on at 100% light output. With filament lamps, it is common practice to cycle the current in a logarithmic manner reducing the current to approx 10% so the lamp never really is off, and then cycling the current back up. This prevents thermal shock of the filament and further reducing the life. The LEDs can be flashed in crisp, true, on off cycles providing a more conspicuous flash.

The PAR-46 version is currently in the works and hope to have it available by early 2011.

Regards,
Jeff Argersinger
Whelen

 

[gismo]

Flashing has no affect on the life of the leds. The beauty of the LED is when flashed, it is essentially instantaneously on at 100% light output. With filament lamps, it is common practice to cycle the current in a logarithmic manner reducing the current to approx 10% so the lamp never really is off, and then cycling the current back up. This prevents thermal shock of the filament and further reducing the life. The LEDs can be flashed in crisp, true, on off cycles providing a more conspicuous flash.

The PAR-46 version is currently in the works and hope to have it available by early 2011.

Regards,
Jeff Argersinger
Whelen

I agree with all you said about flashing LEDs but the notion that pulsing shortens the life of incandescents or that "keep alive" current (which is indeed often used when flashing them) is done to prolong bulb life is a common misconception propagated by the experience we've all had when a light bulb "pops" when turned on. The real reason for the keep alive current is to significantly reduce the inrush current which is detrimental/stressful to the contacts or semiconductors supplying the lamp's current. Thermal cycling of an incandescent lamp isn't what wears them out, it's the gradual loss of conductive material evaporating from the filament which darkens the envelope and creates hot spots on the filament that eventually get so thin the filament breaks. It is true that a lamp left on continuously will provide light longer than one that's turned off and on, but the reduction only occurs the last time the lamp is energized and the weak spot on the filament let's go. All the cycling prior to that event has virtually no effect on life.

 

[azure]

I agree with all you said about flashing LEDs but the notion that pulsing shortens the life of incandescents or that "keep alive" current (which is indeed often used when flashing them) is done to prolong bulb life is a common misconception propagated by the experience we've all had when a light bulb "pops" when turned on. The real reason for the keep alive current is to significantly reduce the inrush current which is detrimental/stressful to the contacts or semiconductors supplying the lamp's current. Thermal cycling of an incandescent lamp isn't what wears them out, it's the gradual loss of conductive material evaporating from the filament which darkens the envelope and creates hot spots on the filament that eventually get so thin the filament breaks. It is true that a lamp left on continuously will provide light longer than one that's turned off and on, but the reduction only occurs the last time the lamp is energized and the weak spot on the filament let's go. All the cycling prior to that event has virtually no effect on life.

Just for clarity, Lance, I think you're saying that the reduction in LIGHT only occurs the last time the lamp is energized, right? If I understood you correctly, the reduction in the filament itself is the result of sustained high temperatures and has been occurring throughout the time it's been running.

BTW I had good lighting on Saturday for a close look at my taxi light and the right side of the filament is definitely missing. Hopefully there is not a secondary problem with the PulseLite system as it could be an expensive fix, and I'm very much sold on flashing as a way to increase visibility in daylight.

I've got the STC paperwork ready to go as well for the Whelens. The only thing holding the show up now is my mechanic forgot to order the new tires and brake pads he is supposed to install at my upcoming oil change. Sigh.

 

[gismo]

Just for clarity, Lance, I think you're saying that the reduction in LIGHT only occurs the last time the lamp is energized, right? If I understood you correctly, the reduction in the filament itself is the result of sustained high temperatures and has been occurring throughout the time it's been running.

Nope, I meant reduction in "life" not light (although when the filament opens the light decreases a lot). You got the rest of it.

BTW I had good lighting on Saturday for a close look at my taxi light and the right side of the filament is definitely missing. Hopefully there is not a secondary problem with the PulseLite system as it could be an expensive fix, and I'm very much sold on flashing as a way to increase visibility in daylight.

All things being equal, I'd expect a landing or taxi light to last about twice as long (total time off and on while flashing) when flashing because it's actually burning only about half the time.

I've got the STC paperwork ready to go as well for the Whelens. The only thing holding the show up now is my mechanic forgot to order the new tires and brake pads he is supposed to install at my upcoming oil change. Sigh.

Unless you have to travel to the mechanic, there's probably not much of an advantage for combining tire and brake work with the oil change and Whelen LED install.

 

[azure]

Nope, I meant reduction in "life" not light (although when the filament opens the light decreases a lot). You got the rest of it.

Gotcha -- "life" in quotes as it was really at the end of its life before power was applied that last time.

All things being equal, I'd expect a landing or taxi light to last about twice as long (total time off and on while flashing) when flashing because it's actually burning only about half the time.

Yes, that is what I would expect too. Still, I only flash the lights when there is a reason to, such as in a busy area, or having been called out as traffic to another aircraft or announced on CTAF. I'm not surprised a 25 hr bulb lasted me >70 hours of flight time, given it was only in use maybe 20% of that time. It could have been changed last summer, as the previous owner never flew at night anyway.

Unless you have to travel to the mechanic, there's probably not much of an advantage for combining tire and brake work with the oil change and Whelen LED install.

You don't know my mechanic. He does as much as he can on one plane before moving on to the next, and the wait for any kind of work is typically >3 weeks. With him it always works best to combine as many jobs as possible.

 

[Dave2]

Just for clarity, Lance, I think you're saying that the reduction in LIGHT only occurs the last time the lamp is energized, right? If I understood you correctly, the reduction in the filament itself is the result of sustained high temperatures and has been occurring throughout the time it's been running.

BTW I had good lighting on Saturday for a close look at my taxi light and the right side of the filament is definitely missing. Hopefully there is not a secondary problem with the PulseLite system as it could be an expensive fix, and I'm very much sold on flashing as a way to increase visibility in daylight.

I've got the STC paperwork ready to go as well for the Whelens. The only thing holding the show up now is my mechanic forgot to order the new tires and brake pads he is supposed to install at my upcoming oil change. Sigh.

Come on Liz we're talking abut David here LOL

 

[azure]

Come on Liz we're talking abut David here LOL

Oh, great. Well since you took the trouble to name names, I should hasten to add that it was an honest mixup -- he wasn't sure whether I was supposed to order the tires and he the lights, or the other way around. Too much to do for one oil change I guess.

I'm just frustrated because I wanted to get it all done quickly and painlessly -- hoping to go for my checkride very soon.

 

[jshawley]

So, being terminally lazy, and needing to cram for an Am. Hist. exam, bottom line: can I install one of these Parmetheus units in my Cherokee 140 with the standard incandescent bulb?
Thanks!

 

[DutchessFlier]

So, being terminally lazy, and needing to cram for an Am. Hist. exam, bottom line: can I install one of these Parmetheus units in my Cherokee 140 with the standard incandescent bulb?
Thanks!

Not sure I understand the question...do you have two lights and want to install one LED and leave one incandescent?

The LED is a direct replacement installation for the PAR 36 bulb, and installs in the exact location as the Par36 without any additional equipment or wiring as long as your wiring is as per the requirements of the STC.