May 14, 2006

One of the many things we did today was try to trouble shoot a couple of issues I’ve been having with the Aileron trim and the flap position microswitch for the AOA. Every now and then, the aileron trim has been running away, and I’ve never been able to figure out why. Since this has been occuring, the AOA flap switch isn’t working correctly. This one is a bit harder to figure out.

We systematically went through each step of the wiring to figure out what the deal was. For the aileron trim, it seemed like we had a switch shorting out somehow, so we dismantled the stick grip, and found nothing. For some reason it’s all working correctly again. We don’t know why though. Everytime I go to the hangar now, I’m going to try it and see if it runs away again. Strange. It’s not a sticking relay, we elinated that as a potential issue first.

So, the AOA thingy. Now this is a very strange one. The AOA Pro from Proprietary Software Systems, now (Advanced Flight Systems) has a wire that grounds when the flaps go down. It was working fine, but one day, it stopped. I’ve no idea why. So, I set about checking it a while ago with a multimeter, and discovered that when the multimeter is in diode check mode (outputting a current) and the probes touched across the microswitch, that the AOA works as it should! Hmmm. So, today, I confirmed my suspicions with a AA battery. We soldered some wires to the battery, and connected it across the microswitch. Sure enough the AOA sensed the flaps correctly. Now, I’ve no idea why this would be the case. I need to call them tomorrow to help me figure out why!

Anybody have any ideas?

Oh, one other thing. In the notes above, I switched my wires to be the same as I’ve seen on other sites. That turned out to be a mistake! I had to swap them over again to make the pump blow instead of suck.