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Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 5:02 pm
by dstates
I’m in the process of putting new LED Nav/Strobe lights on my 170A. I’ve gone with Whelen which have 4 wires (Nav Pwr, Strobe Pwr, Ground, and Sync). I’ve already run new wires to the wingtips. I just got done crawling into the tail of the plane and see I have a problem. I don’t know how I’m going to run new wires through the tailcone. My current single wire goes from the rudder into the tailcone below the horizontal stabilizer and is restrained with a clamp then goes through a small hole in a bulkhead. Can anyone give me an idea on how to run a new wire through this area without having to take the horizontal stabilizer off?

Any help would be appreciated!
Doug

Re: Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 5:15 pm
by GAHorn
Don’t run the coax THRU the hole. Run it around the bulkhead and ty-wrap it to the existing wire or clamp.

Re: Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 5:15 pm
by n3833v
How tight is the clamp? Fasten a wire at the end with solder an maybe shrink tube and pull through.
John

Re: Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 5:33 pm
by dstates
Ok, my first post may have occurred in that moment of frustration that “it isn’t going to be as easy as the wingtip wire routing”.

The “clamp” I’m seeing actually looks like a bent aluminum tube that is at the bottom of the rear tailcone bulkhead (see pictures). It is definitely too small to pull my new cable through. I feel confident I can run a new cable through the tailcone using the large bulkhead holes, but I guess my question is how do I retain the wire inside the tailcone? Or can I just retain it at the front and rear bulkheads and that is good enough?

Thanks,
Doug
185E621C-7A18-4101-B79D-D3579815F685.jpeg

Re: Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 6:19 pm
by GAHorn
AC 43.13-1B addresses this, in Chapter 11, para 96:

11-96. GENERAL. Wires and cables should be inspected for adequacy of support, protection, and general condition throughout. The desirable and undesirable features in air- craft wiring installations are listed below and indicate conditions that may or may not exist. Accordingly, aircraft wiring must be visually inspected for the following requirements:
CAUTION: For personal safety, and to avoid the possibility of fire, turn off all electrical power prior to starting an inspection of the aircraft electrical system or performing maintenance.
a. Wires and cables are supported by suitable clamps, grommets, or other devices at intervals of not more than 24 inches, except when contained in troughs, ducts, or conduits. The supporting devices should be of a suitable size and type, with the wires and cables held securely in place without damage to the insu- lation.
b. Metal stand-offs must be used to maintain clearance between wires and struc- ture. Employing tape or tubing is not accept- able as an alternative to stand-offs for main- taining clearance.

You can Google this and download it from FAA.Gov

While there are not likely any fuel lines in the area in which you are working, NEVER tie electrical wires directly to or supported by fuel lines.

Re: Tail Light Wire Through Tailcone

Posted: Sat Mar 07, 2020 8:38 pm
by dstates
Thanks, George.

I was going to look up the minimum distance this evening. I’ll read through that whole section again.