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Magnetic Interference caused Mavic to fly off on its own.

Hounddog

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Yesterday afternoon I was flying my Mavic, trying to put together a video for a friend of a golf course. The golf course was built on top of a field beside an old smelter and there is a lot of slag, metallic, rock waste in the area. (It was actually built on top of the stuff.)

I have flown my drone in the area before with minimal interference, besides the odd warning, and had been flying over the same spot all day when, briefly after a battery swap and take off, the magnetic interference warning came up on my controller. I ignored it as usual, because it typically hadn't affected the actual flight of the drone, but this time by Mavic began to drift to the side. I increased elevation so as not to hit a post and began to manually attempt to counter the drift so that I could land the drone. Then the drift tuned into a full throttle flight path away from me, I raised the elevation again so as not to crash into any trees but at this point my manual corrections had no effect of the drones flight path.

Thankfully, after running after the drone for a while and watching the controller to see where it was facing I was able to bring it back to me and perform a small crash landing, because it was still drifting while I was landing it.

I know that the problem was caused by the magnetic interference and I don't plan on flying my drone anywhere near that place ever again. I'm just wondering what was different from this flight and the others i had performed the same day. The only difference on my end was that I took of from a new position which was lower in elevation, so it had more slag around it, which i'm assuming would have been the issue. But i don't know how the drone was able to seemingly ignore my inputs and fly away? I've attached the DAT file that I believe corresponds to the specific flight:

Dropbox - FLY021.DAT

My main concern now is that my region has many other similar areas, i'm going to try to avoid them, but if this were to happen again what should I do? At the point where my controls weren't working I tried that Return To Home feature but nothing happened. Is there some way I can switch on full manual control or emergency land so that I don't have to just crash it? Any help would be greatly appreciated.
 
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Yesterday afternoon I was flying my Mavic, trying to put together a video for a friend of a golf course. The golf course was built on top of a field beside an old smelter and there is a lot of slag, metallic, rock waste in the area. (It was actually built on top of the stuff.)

I have flown my drone in the area before with minimal interference, besides the odd warning, and had been flying over the same spot all day when, briefly after a battery swap and take off, the magnetic interference warning came up on my controller. I ignored it as usual, because it typically hadn't affected the actual flight of the drone, but this time by Mavic began to drift to the side. I increased elevation so as not to hit a post and began to manually attempt to counter the drift so that I could land the drone. Then the drift tuned into a full throttle flight path away from me, I raised the elevation again so as not to crash into any trees but at this point my manual corrections had no effect of the drones flight path.

Thankfully, after running after the drone for a while and watching the controller to see where it was facing I was able to bring it back to me and perform a small crash landing, because it was still drifting while I was landing it.

I know that the problem was caused by the magnetic interference and I don't plan on flying my drone anywhere near that place ever again. I'm just wondering what was different from this flight and the others i had performed the same day. The only difference on my end was that I took of from a new position which was lower in elevation, so it had more slag around it, which i'm assuming would have been the issue. But i don't know how the drone was able to seemingly ignore my inputs and fly away? I've attached the DAT file that I believe corresponds to the specific flight:

Dropbox - FLY021.DAT

My main concern now is that my region has many other similar areas, i'm going to try to avoid them, but if this were to happen again what should I do? At the point where my controls weren't working I tried that Return To Home feature but nothing happened. Is there some way I can switch on full manual control or emergency land so that I don't have to just crash it? Any help would be greatly appreciated.
You're right. The incident was caused by launching from a geomagnetically distorted site. Immediately before launch the magYaw/Yaw separation was -7. After reaching 5 meters magYaw/YAW had changed to -106.
upload_2017-8-4_13-15-8.png
I've looked at lot of these incidents. This one has to be one of the more drastic changes in magYaw/YAW separation.

Regarding your comment that the controls weren't working it's clear that the controls had some effect. You would have to run CsvView with a SigPlayer containing the control inputs and the GeoPlayer to see this. But, at the same time, the Mavic was attempting to navigate using a compromised Yaw value. Would it be fair to say that You and the Flight Controller were both trying to control the Mavic causing it to seem like your inputs were ineffective?

In most of these incidents the distortion only extends 1 meter at most. But, with this one the magYaw/Yaw separation keep changing until at least 6 meters.

One thing you can do on subsequent flights is before launch check that the Go App heading indicator is correct. This is the single most effect check that can be done to prevent at launch fly aways.triangle.jpg
 
What's strange is that during a lot of the flight there are huge Yaw/magYaw differences that ARE recognised given the COMPASS_ERROR_LARGE nonGPSCause, but it does still not switch to ATTI regardless (ironic given "nonGPSCause"...), it only did so for about 6 secs or so shortly after takeoff. "I know I can't fly myself but I do it anyway..."

Still maintaining that it's kinda dangerous not to have manually selectable ATTI by default on the Mavic for exactly that reason.

Clipboard01.png
 
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Im new to flying. I took my mavic out the first day... when i went to activate auto land, it began to decend, then about 6" to a foot from landing, it shot up really fast in the air! I had to cancel auto land then pull the throttle down.

Im wondering if it was magnetic interference. Im going to check the data when i get home
 
How high up did it go? Could have been obstacle avoidance?

Approximately 20' (6m) real fast straight up, right before it started decending, from hovering, at about 6' (1.8m) from the ground.

I wonder now if maybe the white concrete activated the sensors. The parking area where i was landing was concrete and not blacktop and there werent anything around it within 15 or so feet. It was a hot humid day as well. Not sure the combination with concrete would have any affect?
 
Was your RTH height set to 6m? :)

Man.. im so new to this, been doing so much online education on the controller settings and such than flying so far.

I noticed a few settings off just now in the controller. Straightened it out and going to go to the same spot later and try the auto land sgain. My flight should be alot smoother this time also since i didnt customize the sensitivity!

Sorry to have hijacked this thread! Thanks for the input. Im out
 
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Thanks for the input guys, ill make sure to check my heading indicator next time!

You're right. The incident was caused by launching from a geomagnetically distorted site. Immediately before launch the magYaw/Yaw separation was -7. After reaching 5 meters magYaw/YAW had changed to -106.
View attachment 18880
I've looked at lot of these incidents. This one has to be one of the more drastic changes in magYaw/YAW separation.

Regarding your comment that the controls weren't working it's clear that the controls had some effect. You would have to run CsvView with a SigPlayer containing the control inputs and the GeoPlayer to see this. But, at the same time, the Mavic was attempting to navigate using a compromised Yaw value. Would it be fair to say that You and the Flight Controller were both trying to control the Mavic causing it to seem like your inputs were ineffective?

In most of these incidents the distortion only extends 1 meter at most. But, with this one the magYaw/Yaw separation keep changing until at least 6 meters.

One thing you can do on subsequent flights is before launch check that the Go App heading indicator is correct. This is the single most effect check that can be done to prevent at launch fly aways.View attachment 18882
 
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