ahrs magnetic anomaly. Check installation

[Ulysse]

I have this message in my g3x.

Is this caused by something integrated in the g3x itself or a separate part of the system?

[Marc_B]

From what I understand it's an issue with a magnetic anomaly with the magnetometer.  Could be install location, wiring passing around the GMU11, or other external magnetic issue.  I've gotten this from time to time with my install and waiting for my shop to check it out.  Do you get this in the air or only on the ground?  Any common denominators when it happens (i.e. turning on lights, flaps, gear, etc.)?  Also, where is your magnetometer mounted?  Mine's in the left wing.

[Ulysse]

Happens only in the air, and it seems to be random. It can happen in uniform level flight.

The magnetometer is located in the back, where the oxygen tank lives.

[LANCECASPER]

22 hours ago, Ulysse said:

I have this message in my g3x.

Is this caused by something integrated in the g3x itself or a separate part of the system?

Are your strobe wires or boxes anywhere near your magnetometer or wiring?

[Ulysse]

On 6/3/2023 at 2:13 PM, LANCECASPER said:

near your magnetometer or wiring?

Strangely, it happened repeatedly on a 4h flight on Thursday. On subsequent flights on Friday and today, respectively 2h and 4h long, it never appeared. Could it be the influence of the content of the baggage area?

[N201MKTurbo]

If it is mounted in the tail, it definitely could be something in the baggage compartment.

[Fly Boomer]

8 minutes ago, Ulysse said:

Strangely, it happened repeatedly on a 4h flight on Thursday. On subsequent flights on Friday and today, respectively 2h and 4h long, it never appeared. Could it be the influence of the content of the baggage area?

Sun spots.

[Ulysse]

Follow up on this topic:

It seems that the problem has been solved by moving a small toolbox containing one screwdriver and a spanner from one side of the hatrack to the other!

[Fly Boomer]

7 hours ago, Ulysse said:

Follow up on this topic:

It seems that the problem has been solved by moving a small toolbox containing one screwdriver and a spanner from one side of the hatrack to the other!

I hope your problem never returns, but I'm suspicious of the "fix".  If it were mine, I would probably continue to pursue the cause.  I guess the current fad is to call it the "root cause".

[skykrawler]

The sensor is often out on the wing - away from other stuff.

 

[Ulysse]

On 6/29/2023 at 3:07 PM, Fly Boomer said:

I'm suspicious of the "fix".

It happened again for no apparent reason. I was in IMC, the gfc500 went crazy, the g3x heading and attitude display made no sense and this is the moment where you wish you had a good old gyro.

I canceled my flight and landed. Moved some stuff in the bagage compartment and the hatrack (my magnetometer is behind). Made a test flight. It happened again for a very short moment but the rest of the flight was fine.

Any suggestion on how to handle this problem?

 

[JimB]

How long have you had the G3 installed? Maybe take it back to the installation shop?

[takair]

5 hours ago, Ulysse said:

It happened again for no apparent reason. I was in IMC, the gfc500 went crazy, the g3x heading and attitude display made no sense and this is the moment where you wish you had a good old gyro.

I canceled my flight and landed. Moved some stuff in the bagage compartment and the hatrack (my magnetometer is behind). Made a test flight. It happened again for a very short moment but the rest of the flight was fine.

Any suggestion on how to handle this problem?

 

Perhaps try to remove everything from the hat rack and baggage area to eliminate that as a cause. You may have an intermittent wiring or bonding issue that causes it. Might need deeper troubleshooting. Be sure it is not a delayed response to radio transmissions  on certain frequencies too. 

[Ulysse]

I am wondering: why does a magnetometre issue affect the attitude indicator on the g3x?