Challenge: Identify this light bulb!

[ZuluZulu]

At some point under prior ownership my wingtip rear facing nav lights were modified.  For one thing, the left and right wingtips, in terms of the sockets and hardware involved, do not even match each other.  For another, the IPC calls for an A508-28, but the A508-28 bulb I bought to replace the burned-out right wingtip light definitely does not fit.  Instead this taller bulb with the filament mounted vertically is in there.  No approved LED replacements yet, damn it.  Can anyone identify this bulb so I can find a replacement?  The burned-out bulb has no identifying markings and I can't figure out what to buy after striking out on the A508.  (Hurry up, Whelen! @OSUAV8TER)

(Photo: A508-28 from Spruce on the left, Mystery Light on the right, pulled from the socket exactly as installed.)

[ZuluZulu]

Detailed view of the Mystery Light (click for full resolution).

[ragedracer1977]

It looks like a T4 halogen bulb to me https://www.lightbulbs.com/product/philips-415588/?source=GooglePPC-ProductAds&gclid=CjwKCAjw1uiEBhBzEiwAO9B_Hesn11cPnZ_IAhnkPLi3vigWiGGjjeHUjEmSZ-UFBwWULWm5VGf2cRoC8XAQAvD_BwE

 

 

 

Edited May 12, 2021 by ragedracer1977

[carusoam]

I looked up the bulb by part number...

And got a few different bulbs... different shapes and wattage...

Most often mentioning that it is an aviation bulb...

Best regards,

-a-

[Yetti]

too easy.   You may not like the answer though.   And someone may not have replaced with what should be there.   An E so lets assume 12 volt.  Trundle on down to homer dan and you can find that in the light bulb section.   Now just pick out a wattage.   There are both 12v and 120v but the base size should be different so need to match it up and read the package.   And there is LED..... that should match the base.   Let's get you started.

https://www.homedepot.com/s/12volt%20bulb?NCNI-5

 

[Yetti]

There is also a more expensive wheelen bulb that may be it.   Cessna tail light bulb is a good search.   https://www.chiefaircraft.com/whl-a508.html

[N201MKTurbo]

Just like my 20s

If it fits it is good, as I sit here watching Mister Goodbar on TCM.

[Yetti]

8 hours ago, N201MKTurbo said:

Just like my 20s

If it fits it is good, as I sit here watching Mister Goodbar on TCM.

Still looking for a STC/PMA/TSO for an incandescent GE Landing light

[PilotX]

Looks like the rear-facing wing recognition light in my Bravo.

[GeeBee]

Personally, I would just buy this and be through with it. The look good and they work good.

 

https://www.aero-lites.com/product-page/led-rear-position-light-wedge-base

[ragedracer1977]

1 hour ago, GeeBee said:

Personally, I would just buy this and be through with it. The look good and they work good.

 

https://www.aero-lites.com/product-page/led-rear-position-light-wedge-base

It's not a wedge base though. It's a pin base

[GeeBee]

Yes, you are correct. I would buy new bases and change it back to the original Whelen design. These will fit, it's what Whelen uses. That way if he wants to use the "approved bulb" an A508 will fit too.

https://www.bulbamerica.com/products/osram-sylvania-tp20x-wedge-base-ceramic-lampholder-socket

 

[ZuluZulu]

I already bought new bases.  I already bought Aero-Lites replacements.  But I can't create time in my mechanic's schedule to help me change them.  So until then I need to find this bulb. 

[ZuluZulu]

17 hours ago, ZuluZulu said:

For another, the IPC calls for an A508-28, but the A508-28 bulb I bought to replace the burned-out right wingtip light definitely does not fit.

(Photo: A508-28 from Spruce on the left, Mystery Light on the right, pulled from the socket exactly as installed.)

For those recommending 14V bulbs, the "28" in A508-28 stands for 28V.  The difficulty in tracking this bulb down is making me think it's an off-the-shelf part.

[ZuluZulu]

14 hours ago, carusoam said:

I looked up the bulb by part number...

And got a few different bulbs... different shapes and wattage...

Most often mentioning that it is an aviation bulb...

Best regards,

-a-

Where did you find the part number?  There's nothing printed on the removed bulb at all.  I know the part number of the A508, but that bulb doesn't fit.  I'd like to have a little chat with whoever decided to change my plane's base and lights!

[carusoam]

31 minutes ago, ZuluZulu said:

Where did you find the part number?  There's nothing printed on the removed bulb at all.  I know the part number of the A508, but that bulb doesn't fit.  I'd like to have a little chat with whoever decided to change my plane's base and lights!

I did a search on the A508-28

To find what ever standard it is...   there were several different looking bulbs claiming to fit that standard...

Best regards,

-a-

[ZuluZulu]

I believe it's been found, via a helpful PM!

https://www.aircraftspruce.com/catalog/pnpages/01-01348.php

https://www.skygeek.com/whelen-h35w28v-lamp.html

[A64Pilot]

10 hours ago, Yetti said:

Still looking for a STC/PMA/TSO for an incandescent GE Landing light

I have not looked, but think there is a landing light TSO now.

‘There not being one is what blocked installation of the LED’s for some time, when Whelen came out with their Parmethius it’s approval basis to install was an STC, which I think Whelen bought from Floats Alaska.

But as there are now LED aircraft landing lights for sale that don’t come with an STC, that leads me to believe that finally there is a TSO for landing lights.

‘For those wondering what I’m talking about, there never was a Technical Standing Order that laid out how bright or what degrees of light or any other performance they had to meet, the old light bulbs were built so long before there was an FAA etc they were just sort of Grandfathered in, but someone came out with this while new technology and they weren’t allowed, which I guess could be a good thing because some of them were about as bright as a cars parking lights.

 

The funny thing is the USCG has had standards that lights must meet for boats , well for almost ever I guess

Edited May 12, 2021 by A64Pilot

[PT20J]

There is a TSO for nav lights. There has never been a TSO for landing lights to my knowledge. Incandescent landing lights were always considered standard parts built to industry specifications -- just like nuts and bolts. Whelen does have STC and PMA approval for its LED landing lights. It's unclear what the basis would be to allow installation of other LED landing lights, but the FAA doesn't seem to care. It is interesting that the original Prometheus, though FAA approved by STC was dimmer than the incandescent light it replaced.

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