I have a sudden problem with both of my HDX ADAHRS units. Last week my avionics guy (among this community’s very best, so don’t think I’m knocking him) accomplished KELLI GIRL’s biannual pitot/static/transponder IFR cert. No problems, no leaks.
On the first flight (day VMC), about 1 minute after takeoff, the gyro- and mag-based instruments want tango uniform. Both ADAHRS tumbled, and not at the same rate or direction. The mag compass just picked a direction and started spinning.
The attached photo shows an example during straight and level flight (I swear it! I can't get the photo to stay upright ). Note the difference between the PFD mag heading and the mag track on the map display.
(Oh, and don't judge my switch alignment. Remember: An amateur built my airplane.)
All the while, I got several continuous and successive “ADAHRS Mismatch” warnings. When I compared the two ADAHRS outputs, each differed from the other, but neither was correct, so I couldn’t pick one.
Meanwhile, the GPS-based information stayed rock solid (the map, ground track, course, ground speed). The pitot/static readings (KIAS, altitude, and vertical velocity) were also reliable, as was the TAS. After landing for fuel and returning home, they worked PERFECTLY on the second flight.
That was Wednesday. It happened again yesterday (Friday): Two flights, the first one with major ADAHRS errors, but the second one perfectly fine.
I called Dynon after Friday’s flights: They recommended I perform a compass calibration which I did on the surveyed Compass Rose at KGLE (thank you 99s!).
In today’s 5 flights, the first three flights showed errors but each subsequent flight showed an improvement over the previous flight. Flights 4 and 5 were perfect. Of note, on today’s last flight I opened up the airborne compass calibration page and noted heading accuracy levels ABOVE 100% so I know the heading is capable of being spot on.
So here’s where I stand. Data from GPS and pitot/static looks rock solid. It appears that the gyro-derived or gyro-influenced information (attitude indicator, turn/slip, and mag heading) are somehow goofed up. Oh, and autopilot and flight director? That was an adventure all its own. KELLI GIRL is red-X for IFR flight until I get this figured out.
Now, I did inspect my ADAHRS units behind the baggage wall: Nothing loose, no misplaced tools, no loose connections. My avionics guy confirmed that he didn’t disconnect/reconnect the units or their electrical connections: He did nothing to them other than check the security of the air lines (no leaks).
I will get back in touch with Dynon to see where they want me to go next. HOWEVER, have any of you run into this issue? How did you resolve it?
On the first flight (day VMC), about 1 minute after takeoff, the gyro- and mag-based instruments want tango uniform. Both ADAHRS tumbled, and not at the same rate or direction. The mag compass just picked a direction and started spinning.
The attached photo shows an example during straight and level flight (I swear it! I can't get the photo to stay upright ). Note the difference between the PFD mag heading and the mag track on the map display.
(Oh, and don't judge my switch alignment. Remember: An amateur built my airplane.)
All the while, I got several continuous and successive “ADAHRS Mismatch” warnings. When I compared the two ADAHRS outputs, each differed from the other, but neither was correct, so I couldn’t pick one.
Meanwhile, the GPS-based information stayed rock solid (the map, ground track, course, ground speed). The pitot/static readings (KIAS, altitude, and vertical velocity) were also reliable, as was the TAS. After landing for fuel and returning home, they worked PERFECTLY on the second flight.
That was Wednesday. It happened again yesterday (Friday): Two flights, the first one with major ADAHRS errors, but the second one perfectly fine.
I called Dynon after Friday’s flights: They recommended I perform a compass calibration which I did on the surveyed Compass Rose at KGLE (thank you 99s!).
In today’s 5 flights, the first three flights showed errors but each subsequent flight showed an improvement over the previous flight. Flights 4 and 5 were perfect. Of note, on today’s last flight I opened up the airborne compass calibration page and noted heading accuracy levels ABOVE 100% so I know the heading is capable of being spot on.
So here’s where I stand. Data from GPS and pitot/static looks rock solid. It appears that the gyro-derived or gyro-influenced information (attitude indicator, turn/slip, and mag heading) are somehow goofed up. Oh, and autopilot and flight director? That was an adventure all its own. KELLI GIRL is red-X for IFR flight until I get this figured out.
Now, I did inspect my ADAHRS units behind the baggage wall: Nothing loose, no misplaced tools, no loose connections. My avionics guy confirmed that he didn’t disconnect/reconnect the units or their electrical connections: He did nothing to them other than check the security of the air lines (no leaks).
I will get back in touch with Dynon to see where they want me to go next. HOWEVER, have any of you run into this issue? How did you resolve it?