Colt rewiring

[Bayou Bill]

I have a late model PA 22-108 project that I am rebuilding. I am about to tackle the rewiring of the main electrical harness. This aircraft has the master switch under the pilot's seat and the remote starter/mag switch on the instrument panel. Can anyone share any hints or upgrade information before I get started? I thought that I would replace each wire one at a time to recreate what I have. I know about the SB on the battery cables. Thanks in advance

[Frank Green]

Be sure to use all the right materials. AC wire doesn't come from NAPA. Nor do wire ends or anything else. Use only approved material installed IAW part 43 standards. Also the tools for installing AMP wire ends are different than you'll find at Sears. Do it right.

[Stephen]

You can replace it one at a time as you said. If you have not done this type of work make sure that you get an experience person to show you techniques, it is slightly different than automotive. As pointed out; use Tefzel wire and good quality conectors. Also, get a good crimping tool, one that ratchets. Each connection should be pull tested, all grounds cleaned and electro-lube (??) coated. Use 43.13 for a guide to the size wire, the last person who installed wires may have been wrong. Also, use the guide for how to properly bundle the wires. Good luck and have fun.

I would suggest getting a copy of the "AeroLectric" handbook on wiring aircraft. It is written by Robert Nuckolls who has worked for years in Wichita, Ks. for the big companies. [He was lead Electrical on the Beechcraft Starship] He also has a forum group that is very helpful and has a searchable database of past posts. this is the link to subscribe: http://www.matronics.com/subscription . The list is AeroLectrics-list.

Although our 50 year old aircraft are obviously airworthy, there have been many changes even within the Shortwing Family during production. One is the use of contactors for the battery/master switch and at the Starter switch. The other is in proper grounding techniques to avoid RF interference in your avionics.

Look in the photo gallery under instrument panels, then go out and look under the panel on your Colt. We have some real craftsmen on this forum. I am sure they will be a great help.

Consider getting rid of that acid bath Piper put under the passenger seat and replacing it with a sealed unit like a concorde. It might not be STC'd for a PA22 but they do make a direct replacement for a Gill 25 or 35. Another complication in our airplanes is the fuel line crossing behing the instrument panel and the in dash primer. Make sure there are no switches or circuit breakers below the primer and that there are no wires attached to the fuel line. As suggested, check out section 43 in the FAR on proper techniques for securing and routing your circuits. Send me a PM if you don't have a copy and I will email the section to you.

One last thing, your Colt probably came with the most basic electrical system using a 20 amp generator. A strobe, Nav/Com, and Xponder have probably been added. That is about 10 additional amps over the origional design load. I have had the fuse on my master blow 3 or 4 times during night VFR, usually on approach to landing due to the added load of landing lights. I just keep on flying to the landing and taxi to parking, then deal with switching out fuses. I might suggest you get involved enough to do a load calculation for taxi, takeoff, cruise flight, and landing. Then have a plan for shedding loads in the air to maintain safe flight and conserve battery power for landing and communications.

[pistoncan]

Nobody has mentioned soldered connections. Is there anything wrong with soldering connectors on the wire?

[Gilbert Pierce]

THe military never allowed soldered connections. Their reasoning has been borne out by my experience. If you solder a connection into a terminal it makes the wire rigid. Any movement or vibration at that point will cause the wire to break rather then flex.

[Bayou Bill]

Gilbert, is "tinning" the wire end before squeezing the terminal on ok or can that also lead to breakage such as soldering the terminal on?

[Bob Jagodzinski]

THe military never allowed soldered connections. Their reasoning has been borne out by my experience. If you solder a connection into a terminal it makes the wire rigid. Any movement or vibration at that point will cause the wire to break rather then flex.

Back in the '60's all of the Cannon Plug wires were soldered on our C130A's.
Bob 5656H

[Gilbert Pierce]

Back in the '60's all of the Cannon Plug wires were soldered on our C130A's.
Bob 5656H

Yes they did Bob and they broke. I spent too many hours on the floor under the panel of a C130 fixing wires where they had broken right where they went into the pin. On the C130E (Air Force) they put instruments in from the front so you could easily remove them. The only problem was they didn't leave enough wire where you could pull the cannon plugs out far enough to replace the wire where they broke at the interface of the pin. When we got C130G's and EC130Q's (NAVY) they were crimped.

[Glen Geller]

Gilbert, is "tinning" the wire end before squeezing the terminal on OK or can that also lead to breakage such as soldering the terminal on?
If you tin the bare end of the wire, it will be impossible to get a solid crimp on it -either you are a mere mortal and don't have the strength, or if you are Clark Kent you just damage the tool.
I used to build radar systems for the Navy (SPN-43, SPS-48) & Air Force (PAR) and we used solder on electronics, crimpers on connectors, per MIL-Spec.
Don't use solder to install connectors. Use the correct size & type of wire, connectors and tools as indicated in previous posts here and in the FARs.
If you are unsure or don't have the correct tools, get a properly equipped colleague or your A&P to assist you and verify your work. A small investment to make it right and keep it legal.
Remember, when the accident investigators find anything 'not airworthy' on your plane, even if it's not related to the cause of the crash and ensuing fire, the insurance company will not send a check to your widow.

Happy Holidays!
GG