I have a new (to us) RV-10 that was built about 10 years ago. It has developed a problem where the Advanced 5600 has begun to lose it's sense of direction and gets confused about our magnetic heading, often showing a slow but constant drift, which messes up the attitude information.
After discussing with Advanced Flight Systems tech support, they suspected the magnetometer (a Crossbow unit) was either going bad or some other source of interference was present. So they sent a loaner unit out, which I swapped in (with the requisite swearing and bodily twisting). Unfortunately it failed to calibrate on 2 of 3 attempts. And on the one "successful" attempt, it still showed the slow drift problem.
So they suggested I get back there with a handheld compass and try to find stray magnetic field sources. That's as much fun as it sounds like it'd be.
Well, since a picture is worth a thousand words... Here's what I found. There was some interference at the battery hold down bracket. But there was also a field coming from the elevator pitch servo, which is only about a foot away from the magnetometer. The mag is the gold box just below the orange tube on the upper left. Part of me wonders how this ever worked well!
I'm looking for some advice on the least invasive solutions here.
Should I try wrapping the servo with some anti-EMF fabric in the hopes that it'll dull the field enough?
Do I have to seriously think about relocating it somewhere else? There aren't many other good reachable options back there. I'd probably have to extend the DB9 cable, which isn't a big deal. But maybe going to a wing is going to make more sense? (I have no idea how much work is involved in doing so.)
Thoughts? Opinions? Ideas?
Thanks,
Jeremy
After discussing with Advanced Flight Systems tech support, they suspected the magnetometer (a Crossbow unit) was either going bad or some other source of interference was present. So they sent a loaner unit out, which I swapped in (with the requisite swearing and bodily twisting). Unfortunately it failed to calibrate on 2 of 3 attempts. And on the one "successful" attempt, it still showed the slow drift problem.
So they suggested I get back there with a handheld compass and try to find stray magnetic field sources. That's as much fun as it sounds like it'd be.
Well, since a picture is worth a thousand words... Here's what I found. There was some interference at the battery hold down bracket. But there was also a field coming from the elevator pitch servo, which is only about a foot away from the magnetometer. The mag is the gold box just below the orange tube on the upper left. Part of me wonders how this ever worked well!
I'm looking for some advice on the least invasive solutions here.
Should I try wrapping the servo with some anti-EMF fabric in the hopes that it'll dull the field enough?
Do I have to seriously think about relocating it somewhere else? There aren't many other good reachable options back there. I'd probably have to extend the DB9 cable, which isn't a big deal. But maybe going to a wing is going to make more sense? (I have no idea how much work is involved in doing so.)
Thoughts? Opinions? Ideas?
Thanks,
Jeremy
