Tuesday, May 17, 2011

Taking a Reeding

I had some experience in troubleshooting an RV-12 avionics problem last year and through that I learned a valuable lesson: label the wires!


I finished up page 31-05 by pulling a total of three wires through the wire duct and out to the sides of the plane. One went to the left side where it will carry the signal from the wing lock pin position sensors. The other two went to the right side of the airplane. One will attach to the fuel level sensor in the fuel tank, and the other will attach to.... nothing. It's a GPS Data Out wire that can feed a last known position to the Emergency Locator Transmitter if I buy an optional piece of equipment. I won't.

Pulling the wires through takes a lot of concentration to make sure that I don't end up missing a string when each job is finished. I guess I could label the strings to make it easier now that I have a label maker, but I suppose that could be construed as just showing off.

The next job was one of those deceptively easy sounding jobs: put four snap bushings in. Sounds easy, then you see that they're tiny little bushings destined to be placed into very difficult areas. The holes are hidden behind cross members and other parts of airplane. The left side was easy since that's currently the "bottom," but the right side was trickier because it's now the "top." Those were more challenging because they were harder to reach, harder to see, and the consequences of dropping one of the bushings was almost certain loss of the little critter.

I dropped the same one twice.

Found it both times. I'd go out and buy lottery tickets tonight, but I think that was my quota of good luck for the month.

Just before calling it quits for the night, I got out the multimeter and tested the reed switches that will be mounted at the back of the armrests. For both of you that have been wondering why I spelled 'reading' in the title of this post as 'reeding,' now you know. These little switches do nothing but sense magnetism. If you remember, I put magnets down into the silver pin stops in the wing pins a few pages ago. The idea is that these switches will be positioned so that they will sense the magnet in the wing pin stop pins if, and only if, the pins are in correctly. This will (in theory) prevent someone from inadvertently flying away with the wing pins not secured. I say "in theory" because there's an override switch on the panel; someone will inevitably use the override switch and fly off with unsecured pins someday.

Anyway, I tested the switches because it is apparently difficult to get them positioned so that they work. I wanted to rule out the question of defective switches before beginning the installation.

They worked.

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