Garmin install magnetometer

[VanGo]

Recently had a complete avionics install. Initially it worked fine, however after a few weeks we get a message stating “AHRS magnetic anomaly-check installation”

The shop is very cooperative in doing their warranty work.  They feel there is some

electronic interference occurring and plan on moving the location of the magnetometer.  They are good avionics mechanics, but not Mooney specialists.  Anyone else experience this?

[chriscalandro]

Doesn’t have anything to do with the Mooney and you don’t need a Mooney mechanic. 
 

you should listen to the shop. Sounds like they are correct. It’s not complicated. 

Edited August 9, 2023 by chriscalandro

[Bolter]

As a reference, my J had the factory magnetometer in the pilot-side wing, outside of the fuel area, near an access panel.  The Garmin sensor with the G5 install used the same place without any issues.  If yours is not in this location, that may be a factor.  -dan 

[Ragsf15e]

1 hour ago, VanGo said:

Recently had a complete avionics install. Initially it worked fine, however after a few weeks we get a message stating “AHRS magnetic anomaly-check installation”

The shop is very cooperative in doing their warranty work.  They feel there is some

electronic interference occurring and plan on moving the location of the magnetometer.  They are good avionics mechanics, but not Mooney specialists.  Anyone else experience this?

Mine is not in the wing, but in the tail cone behind the battery.  However, it’s on a shelf well up and pretty far behind the battery and the avionics.  Seems like either the factory location (outer wing area) or tail can work if they’re careful.

[ArtVandelay]

Mine is not in the wing, but in the tail cone behind the battery.  However, it’s on a shelf well up and pretty far behind the battery and the avionics.  Seems like either the factory location (outer wing area) or tail can work if they’re careful.

Mine too, I estimate they are about 2-3 feet from the AP servos…any motor or any wire with a large enough amperage will cause interference with the magnetometer. There’s a free app “magnitude” that will measure magnetic field strength you can use to check areas, just be sure strobes, landing lights, and motors are operating.

[Utah20Gflyer]

My magnetometer is also in the tail cone, probably half way back on the pilot side.  

[N201MKTurbo]

Mine is in the right wing. It has been trouble free.

[Pinecone]

There was a report of someone with issues with one tail cone mounted.  It was something they stored on the hat shelf.  Moving it to the floor of the baggage area solved the issue.

They are VERY sensitive.  I would put it out in the wing.

[ArtVandelay]

Mine is in the right wing. It has been trouble free.

Do you have the wing landing/taxi lights? LED or incandescent?
Some AP roll servos are the left wing, some are in the right.

There’s no 1 right answer, you need to go through the process of doing a magnetic field survey, but as a rule, try to stay 2 feet from motors and high amperage wires.

[N201MKTurbo]

1 hour ago, ArtVandelay said:

Do you have the wing landing/taxi lights? LED or incandescent?
Some AP roll servos are the left wing, some are in the right.

There’s no 1 right answer, you need to go through the process of doing a magnetic field survey, but as a rule, try to stay 2 feet from motors and high amperage wires.

The only thing in my right wing is a strobe power supply and the nav light. The magnetometer is about 5 feet from anything electrical, except the wires. It is about 18 inches from any wiring.

[flyboy0681]

22 hours ago, Utah20Gflyer said:

My magnetometer is also in the tail cone, probably half way back on the pilot side.  

When the GI 275 was installed the shop built a shelf in the tail for the magnetometer but we could never get an accurate calibration. We eventually had it moved to the right wing and now it's spot on.

[EricJ]

1 hour ago, flyboy0681 said:

When the GI 275 was installed the shop built a shelf in the tail for the magnetometer but we could never get an accurate calibration. We eventually had it moved to the right wing and now it's spot on.

That looks like it would be subject to a lot of vibration, although I don't know if that would affect calibration.

[ArtVandelay]

I assume the black wire (green) is an antenna wire, so that shouldn’t be a problem.

But what looks like a conduit (yellow) and what is for?

[ArtVandelay]

You can see my shelf at the very top (secured very securely):

[N201MKTurbo]

3 minutes ago, ArtVandelay said:

I assume the black wire (green) is an antenna wire, so that shouldn’t be a problem.

But what looks like a conduit (yellow) and what is for?

I think it is the fresh air plenum from the dorsal fin air scoop.

[ArtVandelay]

I think it is the fresh air plenum from the dorsal fin air scoop.

In that case, should not affect the magnetometer.

[OR75]

2 hours ago, ArtVandelay said:

I assume the black wire (green) is an antenna wire, so that shouldn’t be a problem.

But what looks like a conduit (yellow) and what is for?

the black is a coax (com antenna) , the nylon conduit (yellow) is the static line (two static holes , one on each side of the fuselage tail cone  

[ArtVandelay]

the black is a coax (com antenna) , the nylon conduit (yellow) is the static line (two static holes , one on each side of the fuselage tail cone  

Yeah, thanks, but I meant the gray conduit at the top.

[Ulysse]

On 8/10/2023 at 2:05 PM, Pinecone said:

There was a report of someone with issues with one tail cone mounted.  It was something they stored on the hat shelf.  Moving it to the floor of the baggage area solved the issue.

That was me. Unfortunately, it happened again, so the problem is still unsolved. The magnetometer is in the tailcone.

This issue can cause your attitude indicator to become unreliable if you have a Garmin panel. See @PT20J's post on the topic "g5 as backup of g3x -> GFC500" about this.

I am scared of flying in IMC now until this issue is solved. Please do let us know if you find the origin of the problem.