MGL Avionics User Forum

I just installed SP-9 AHRS in my little RotorWay helicopter. I put it on velcro underneath the seat on a fairly rigid 0.050" thickness shelf (I could potentially beef the shelf up by adding additional metal). I also have SP-6 compass mounted in front and Discovery Lite EFIS. Generally the system works well, but occasionally I see "AHRS Fault attitude suspect" flash for a split second, but quickly goes away. I made a test flight in the pattern and noticed that the message seem to show a bit less frequently. My question is - does the unit "learn"/self calibrate and the message would eventually stop flashing?

Thanks a lot!
-V

I think I figured what the issue is: I noticed that the little electronics PCB circuit board is sliding a little bit back and forth within the unit housing. I undid the two self tapping screws on the front of the unit and noticed that there is a little felt pad attached to the back wall of the housing - looks like this little felt pad was meant to keep the PCB board stationary in the unit. It looked like the felt had compressed (probably with time) and this allowed the PCB board's movement. I placed 2 little rubber squares on each side of the felt pad, re-inserted the PCB board and screwed back the front of unit. The rubber squares did the job of stopping the movement of the PCB. I did the test flight with this modification and no longer see the "AHRS Fault attitude suspect" messages flashing! It's probably a good idea to test these SP-9 and SP-7 units for movement of the PCBs.