As some of you may know, I maintain a couple of blogs. The most popular is the one about our flying adventures in C-GDKX. The other one deals with operating and maintenance issues--this one.
I haven't written anything here for quite a while but since I had a very satisfying day--mechanically speaking, that is--I decided I would write it up. Kind of a log of "owner performed maintenance", for the record.
At the last annual in May, Chris my AME (who's an awesome mechanic) noted an item on the snag list-- "alternator noise suppressor loose"--but elected not to fix it. When I mentioned it to him, he said that the noise suppressor didn't really do anything and it wasn't worth his time to pull off the alternator to fix it. He said he just turned it to tighten it as best he could and left it like that.
I felt it myself and sure enough, it was slightly loose. There was no danger of it coming off as it had turned to the point that it was impacting the alternator bracket and couldn't move any further. So no safety issues.
Still, I didn't like the idea of something loose under the hood, so to speak.
Interestingly, several months ago, the radio started making occasional static noises. It seemed to happen only on take-off and disappeared once level in cruise. It wasn't a big problem as you could still hear transmissions through the static, but it was annoying.
A little more diagnosis revealed that it only happened under full throttle and disappeared when the throttle was reduced. Hmmm. The engine vibration is highest at full throttle, I wonder if a lose wire is vibrating and creating the static...what a minute...could be the loose noise suppressor?!!!
With that revelation I was now fully motivated to pull off the alternator and tighten the suppressor to see if that would fix the problem.
Now I need to mention that in a car, removing an alternator is no big deal. You simply unbolt it, loosen the belt, unplug a single connector and remove it. But light aircraft alternators are dinosaurs. In fact the alternator on my plane is the same as on a 1960's Ford. Instead of a single plug, there are seven--count them--seven wires that connect to three separate posts. Three on the BAT terminal, one the FIELD terminal and three on the GND terminal. In addition, all these wires are jammed into a tiny space between the back of the alternator and the front baffle on the engine.
I've had the alternator off before (actually to install the noise filter back in the day) and it's not a fun process. The wires are old and brittle and you have to be super careful not to break anything. But I figured the benefits outweighed the risks, so decided to plow ahead.
I got everything off ok and was able to tighten the suppressor. I used a couple of drops of Locktite this time to make sure things stayed put.
Then is was time to reconnect everything. It did not go well.
I simply couldn't get the nut back on the BAT post no matter how hard I tried. There was so little room I had to use a screwdriver to push back the rubber cover and simultaneously push down the wire terminals. I pushed harder and suddenly--snap!!!!--oh *&^*^*!!! I had broken the wire that connects the wire shield to ground.
And to make matters worse, the shield wire was already short and there was not enough wire left to simply reconnect another ring terminal.
I'm so snookered, I thought. I'm in way over my head and will need to get Chris to bail me out. So cap in hand I drove over to Chris's shop. He was crazy busy with airplanes lined up out the door. There was no way I was going to get him to drop what he was doing to help me. I would have to get in the queue. It might be days, maybe even a week before he could help me.
However, he was kind enough to listen to my predicament about the broken ground wire. Some mechanics would berate you for screwing up but Chris was totally cool. He quickly said: "That's not a big deal. That wire you broke runs up to the voltage regulator on the firewall and the factory put a service loop in the wire when it was installed. You just need to pull some more of the wire down to the alternator and you're in business. I've done it myself many times."
Yippee!! I felt SO much better! Not just because he told me the solution, but it was his trust in me that I could to it that was incredibly gratifying and a huge boost to my confidence.
So after gathering the appropriate tools, I went back to the plane and slowly and methodically repaired each of the wires, reconnected everything and reinstalled the alternator.
I pulled the plane out of the hangar and with some trepidation, started the engine, half expecting several circuit breakers to blow! Thankfully, everything was nominal, so I taxied to the runway, did my runup (all normal) and took off.
And in the full power climb to altitude??!!!! NO STATIC ON THE RADIO!!! WHOO HOO!!! FIXED!!!!!
Now in closing, I need to say to those of you who are not mechanically inclined, this story may sound like much ado about nothing. "You just fixed a broken wire! What's the big deal!"' And you're probably right. But you've no idea of the incredible satisfaction it gives when you correctly diagnose a problem (especially an aircraft electrical problem) and then fix it yourself--particularly when you initially felt the fix was way beyond your pay grade--yet you managed to do it.
It was, I said at the top, a very mechanically satisfying day.
