Landing Light Surprise

[MoonlightVFR]

Recently replaced the original landing light lens in my C 170B.

Original was 63 years old, still intact but extensively crazed. Tended to mute the lighting performance.

There is a line of trees 120 ft from hanger door. Aircraft was in hanger, door open.

Surprise was to see clearly and distinctly two different areas illuminated when landing lights switched on.

The tree line over 100 feet away and an approximately 20 ft circle of light on the hanger floor.

After 40 years with 90C I see the two light patterns. Happy surprise.

How do they do that?

[Kurt Aichele]

In the MX library. Thanks, George.
http://cessna170.org/forums/viewtopic.p ... ment#p3201

[bagarre]

edit. I was backwards. Ignore me.

[Bruce Fenstermacher]

edit. I was backwards. Ignore me.

What, did someone post something?:lol:

[GAHorn]

edit. I was backwards. Ignore me.

What, did someone post something?:lol:

WHO EVER told him we did NOT ignore him..???

(Just kidding, of course...)

[GAHorn]

In the MX library. Thanks, George.
http://cessna170.org/forums/viewtopic.p ... ment#p3201

Check that link again, as I have added another document from Cessna on Landing Light Installations.

[rnealon1]

I purchased new Whelen Parmetheus G3 PAR LED landing and taxi lights while at OSH. They worked great but 2 issues arose:

1. When I turned on the taxi light (first position of the switch) it worked great, but when the landing light is turned on there is loud static noise on the COMM radio (GNC 255). The avionics guys say a shielded wire and possibly a ground wire needs to be run vs. the original wiring.

2. The landing/taxi light lens has no gasket (nor is one shown in the IPC) and a gap exists on both sides. Looks like someone duct taped it from the inside years ago.

Any thoughts on either of these issues? I put the incandescent bulbs back in for now.

Thanks,

Bob

[Bruce Fenstermacher]

A pic of your lens might be helpful…but no gap should exist. (no gasket either)

I ordered a new lens for our 172 from Spruce and it arrived too small. It was returned and a second one fit fine.

Webmaster note. The above original post by GAHorn was lost due to admin software failure and is being manually entered here, unedited in its entirety, as it was not included in our latest backup.

[n2582d]

2. The landing/taxi light lens has no gasket (nor is one shown in the IPC) and a gap exists on both sides. Looks like someone duct taped it from the inside years ago.

Bob, I’m not clear whether the gap is a span-wise gap or if the gap is between the leading edge of the frame and the lens. If the issue is a gap at the leading edge, would it work to add some sort of filler between the retainer (p/n 0523115-3) and the rear edge of the Plexiglass to force the lens forward— say Koroseal lacing or weedwacker string trimmer line? If you need a frame I have one to sell. I’d offer the lens as well but it’s crazed — you’re better off buying new. Click on photo to enlarge.

IMG_0534.jpeg

IMG_0536.jpeg

IMG_0537.jpeg

[rnealon1]

Hi guys,

The gap is at the leading edge, so that the lens is set back from the bracket/frame perhaps 1/4". I ordered a new lens from Univair and will see if it fits better (or worse!). This is a good idea to adjust from the rear edges. I will let you know how it turns out.

Thank you for the offer of the frame; I will let you know if that becomes necessary.

Thanks,

Bob

[rnealon1]

Here are photos of the landing light installation, with the gap showing around the leading edge frame. I got a new LP Aeroplastics lens but have not had a chance to check the fit yet.

Still wondering if anyone has experience with the LED bulbs causing radio noise.

Thanks,

Bob

20231027_155918.jpg

20231027_155928.jpg

[IA DPE]

I only have an LED as my Taxi Light. Landing Light is still old incandescent. The LED causes no noise in either COM radio.

Hope you find the source of your frustration.

[rnealon1]

Thanks for that information. I was also only getting the noise with the landing light, not the taxi light.

Will let you know what we find.

Bob

[cessnut]

Try running a temporary ground wire all the way back into the cabin and see if it helps with the noise.

[GAHorn]

Bob, if you decide to run shielded wires to those LED lamps, ground only ONE end of the shielding to the airframe to avoid a “ground loop”. I don’t know that will resolve your noise issue, but a shielding “ground-loop” is often an issue in audio circuitry.