Cliff Goldstein
Member
message comes up when turning left through 90 degrees or right through 210 degrees. then goes away after a few seconds.
Van's Air Force
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gmu22 AHRS Magnetic anomaly Check installation
- Thread starter Cliff Goldstein
- Start date
Cliff Goldstein
Member
RV14 installation verified wiring, and AHRS
Cliff Goldstein
Member
RV14 INSTALLAION ERROR verified wiring, AHRS pitch and roll aircraft level, aircraft passes all tests but comes up with anomly when passing through 90 degrees in left turn and 210 in right turn. usually a turn of 90 degrees thru those headings. Rate of turn doesn't affect message coming up. Temp probe co located in same bay. Heading remains accurate inspite of message coming up. the fact that the message comes up repeatedly is different from other similar errors. A second GDU22 was tested with the same results indicating location or wiring. Location is per the wing build plans and we have two other RV14's witht he same installation without issue. appreciate any suggestions as to next step.
thank you,
cliff
thank you,
cliff
PilotjohnS
Well Known Member
It took me 6 months to solve this.
Mine was caused by magnetometer not being calibrated. Every time I tried to cal during ground idling, I would get an error message "plane in motion" . Finally I pulled the plane to a large asphalt area (no rebar), turned on the master, started cal, and pushed the plane around in a circle with no engine running. Got it cal'd and now, no more error message.
Mine was caused by magnetometer not being calibrated. Every time I tried to cal during ground idling, I would get an error message "plane in motion" . Finally I pulled the plane to a large asphalt area (no rebar), turned on the master, started cal, and pushed the plane around in a circle with no engine running. Got it cal'd and now, no more error message.
Cliff Goldstein
Member
have calibrated with no issues always checks out, done mine with engine running. I could try doing with engine off to see if it makes a difference. thank youRV14 INSTALLAION ERROR verified wiring, AHRS pitch and roll aircraft level, aircraft passes all tests but comes up with anomly when passing through 90 degrees in left turn and 210 in right turn. usually a turn of 90 degrees thru those headings. Rate of turn doesn't affect message coming up. Temp probe co located in same bay. Heading remains accurate inspite of message coming up. the fact that the message comes up repeatedly is different from other similar errors. A second GDU22 was tested with the same results indicating location or wiring. Location is per the wing build plans and we have two other RV14's witht he same installation without issue. appreciate any suggestions as to next step.
thank you,
cliff
oaklandaviator
Well Known Member
It’s probably the calibration. Took months for me to get rid of the same message on my new to me 8. Passed the calibration each time but it was off just a touch. I must’ve done the calibration three or four times. I finally took it to a huge open area of ramp with no grates on the ground or hangars nearby. Taxied slowly forward while ensuring gps track was exactly north then started the calibration again with engine on and avionics and lights. Finally got it to not only pass the calibration but to not give the message, in my case, while flying northerly headings.
I’d wager a bet this will solve your issue.
I’d wager a bet this will solve your issue.
I had a very similar problem. Banking left it would cause the error to appear 75% of the time, and it would quickly go away. I redid the calibration multiple times on an asphalt ramp that had a painted compass rose. Each time, the calibration would complete successfully. Eventually move the GDU22 from the recommended Vans wing mount to the empennage. Made a simple shelf to mount it on. Re-calibrated once and haven't had an error with 100 hours of flying. It took about 4 hours on a Saturday to move the GDU22. Hard to tell if I was lucky and got the calibration right the last time, or there was something in the wing causing interference. The units seem to be extremely sensitive/finicky. The decision to move the GDU was based on reading other post that were having similar issues. Some had them in the empennage and moved them to the wing, other did what I did.
I too had difficulty with the GMU22 installed per Van's plans in an RV-14A. I calibrated multiple times and at different airports. I consistently got AHRS magnetometer installation warnings. I moved the temperature sensor away and that made little difference. I finally made up an extension cable and mounted a bracket to the wing tip. 100 hours later with no more warnings.
