Ground for Lighting

[Mel]

If references help, I was an avionics technician in the USAF for 6 years.
Over 40 years in electronics with Texas Instruments.
Airframe ground works fine!
Mel...DAR

[az_gila]

Can the aluminum and electrical connector interact and corrode. DO you cover it with some corrosion protection or sealant it?

Pictures? Cheers George

George, I hope you are only testing us....

The answer to the above is very clearly given to us by the FAA in, what else, AC 43.13-1B.

Table 11.14 on page 80 of this section covers it to the letter.

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2011.pdf

The hardware used depends on the materials involved... if the correct hardware is used, then the corrosion problems and dissimilar metal issues are taken care of.

As always, the AC 34.13 is the bible.

gil in Tucson

PS the MIL handbook recommends the same procedures...

[L.Adamson]

Originally Posted by Mel

If references help, I was an avionics technician in the USAF for 6 years.
Over 40 years in electronics with Texas Instruments.
Airframe ground works fine!
Mel...DAR

Since my 6A spar is anodized, and everything else was two part epoxy primer, neither of which will conduct current on the surface, I ran a ground wire to the inboard rib, since I didn't want to totally depend bolts or rivits making a connection through scratches or un-primed drill holes.

Other than that, the wing lighting and tail light, grounds through the frame, while radios & gauges ground to the main firewall/battery ground

[gmcjetpilot]

Originally Posted by az_gila

Can the aluminum and electrical connector interact and corrode. DO you cover it with some corrosion protection or sealant it?

Pictures? Cheers George

George, I hope you are only testing us....

The answer to the above is very clearly given to us by the FAA in, what else, AC 43.13-1B....

Nope, no test; that is perfect, just what I (WE) needed. I knew I saw it somewhere. My point, people slap metals together in their airframe grounds that are incompatible. Add mosture and current = battery. KEY uses aluminum washers directly adjacent to the structure on each side, and than Cad plated hardware. Cad plated AN hardware is common so that's good. I have seen copper which is worse than steel. Depending on the type of terminal finish Cad only may be needed. Whatever you do, no tinned copper against aluminum structure.

We thank you.
I Thank you George

Originally Posted by billy d

I agree with Mel...All the extra ground leads produce ground "Loops" and interference with Nav /Sound Equip. One solid ground on the airframe does it.
Billy D

Billy D, ground loops as I understand it has to do more with audio devices, where the phone/mic jack is grounded in one place and the electronics are grounded in another, producing two Gnd paths, thus a GROUND LOOP, for example. It is critical for avoiding audio issues, which should have a SINGLE point ground NOT anywhere on the airframe. That's my story and I am sticking to it.

You can ground an item with a dedicated ground wire and not have it also airframe ground. Some items like NAV lights are case ground and harder to isolate from the airframe, but my Nav lights, like everyone's, are in a fiberglass wingtip, so it needs at least a jumper wire to wing structure anyway.


The ground wire/strap from the NEG side of the battery to the engine or firewall might not be so "hot" by the time it gets to the wing tip? It should be groovy, but a good ground strap to the airframe; (may be) also a fuselage to wing strap would be a good idea? Just a thought.

If the main airframe ground strap comes loose it can play heck with your whole electrical system if airframe grounded. When there was an electrical problems, many times it was from poor grounds.

George

Originally Posted by Mel

If references help, I was an avionics technician in the USAF for 6 years. Over 40 years in electronics with Texas Instruments. Airframe ground works fine! Mel...DAR

Sufficient overkill in qualifications, thanks Mel. You got to love the wealth of knowledge on the VAFNET forum. I hear you but I am scared of airframe grounds for some weird reason? I guess I will have to get over it. Cheers G

[mikehoover]

Originally Posted by Mel

No extra ground wire is necessary. Airframe ground is fine for all these applications; nav, landing lights, strobe p/s, fuel gauge senders, etc.
Mel...DAR

If I ground my landing lights, nav lights, strobe lights in each wing to the wing main spar toward the outboard end (pitot heat and AP servo too?), is there a need to run a ground from the fuse to the wing spar roots to assure a solid ground? Thanks!

[szicree]

I think somebody is gonna have to check this with a meter, but it seems like with the gazillion bolts holding the wing on that the connection would be made someplace.

[N162RV]

I was at just about dark yesterday when I turned on the Nav Lights and my Vans oil temp and fuel pressure gauges would peg out. I have seen some minor fluctuations in the past but this was by far the worst.

At the time I had been flying for about an hour or so and it was pretty hot outside as well. Im thinking it has something to do with the ground for the nav lights. The lights are located in the fiberglass tips and have a grounding wire attached to an end rib. Any thoughts?

[db1yg]

I grounded my nav/landing lights locally to the outboard rib--drilled a hole, used a fast on on the ground wires, used a star washer to "dig in" to the aluminum. Absolutely no noise in my audio system. I also talked with Bob Nuchols before doing this. Strobes are grounded to the power pac and the a/p servo (located in wing) have ground runs to the fuse.

Good luck,

db

[shuttle]

Resurrecting an old thread.......

General concensus on this thread was to ground wingtip light units locally to the airframe at the outboard rib.

I will be installing the Duckworks MR16 HID upgrade into my wigtips with an HID ballast mounted on that outboard rib.

Does adding HID ballasts into the equation affect the 'local ground' recommendation?

Thanks in advance...

[David Clifford]

I just ran the wiring in my wings for the HID's, ect. I ran a seperate ground for each item I powered an am not using the airframe for ground. You may want to read this for some good info: http://www.bluemountainavionics.com/download.php Scroll down for the "Aircraft Wiring For Smart People" download. Its free.