Inflight Compass calibration revealed...

[RV6-KPTW]

This calibration is really nice but revealed that I have something wonky with one of my ADHRS'. 

I have occasionally gotten a compare error and after picking the more believable ADHRS, it would not appear again that flight.  My wife has been with me for most issues and it never seemed to happen when I was alone.  So I blamed her.  The compare errors became constant so I thought to do this in air calibration.

I did it and the backup went to 100 in the two 360's but the primary never got off 0.  This seems bad.  Are there additional diagnostics I can perform that would be helpful in determining next steps?

Thanks

 

[Dynon]

Where are you ADAHRS? If you've mounted them under a seat, having someone with a bag or keys in their pockets can affect things. Are you saying that when you do the in-flight calibration, the quality indicator never comes off 0? That could imply that there is something wrong with your magnetometer.

 

[RV6-KPTW]

I fly an RV6 and my ADAHRS's are about two feet aft of the baggage compartment bulkhead about two feet off the bottom skin on a purpose built shelf. The units are stacked so any major magnetic interference should impact both units.

There once was a time when my wife was bringing onboard a handbag that had a large magnet in the closure device. I have been diligent in frisking her before flights.

And yes, I am saying that QI seems to flicker but never comes off 0. Anything else that I can do to diagnose?

Thanks

 

[Dynon]

This does seem like there might be a problem with the magnetometer given you were already having issues with it. A diagnostic log could be interesting here, best taken. Assuming you only did a couple of 360 maneuvers, you could try a calibration with some greater pitch/bank variation (wing overs, steep turns, ...) and see if that gets it. But probably we ought to see that ADAHRS here.

 

[RV6-KPTW]

I will try the more vigorous maneuvers and provide a log. 

Thanks

 

[dlloyd]

I have the two ADAHRS side-by-side behind the baggage bulkhead in my RV7. When there is a passenger or the belts are fastened tight, all is well. When the belts are left loose or fall back in the baggage, it causes as much as 20 degrees variation on one ADAHRS. Doesn't sound like your problem but still something to be aware.

 

[RVDan]

Beware the cables the shoulder harnesses attach to are magnetic. When the shoulder straps arent taught, the cables may be getting close to the ADAHRS

 

[jakej]

That's one of the reasons I install the ADAHRS units to the upper portion of the next bulkhead aft of the baggage one, nice & high & out of the way of ferrous items

Jake J

 

[RV6-KPTW]

I too installed just forward of the next bulkhead aft of the baggage bulkhead and near the top. It is difficult to find a spot in a 6 that is completely free of possible influence. I have also noted an occasional issue when the right seat is on occupied and there is movement in the shoulder restraining cables. I may have to rethink this location regardless. Oh for a remote magnetometer....