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Mavic Mini uncontrolled fly away

ManiakjeNL

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Hello,

I'm new to this forum, so a quick introduction. My name is Raymon and i am a proud owner of a Mavic Mini.
Today i was flying in Red Rock Canyon (Near Las Vegas) and i almost crashed my Mavic Mini. Shortly after take off my drone flew away in high speed (S mode was active). My Drone was heading to a mountain with high speed while i was not touching the controls. I panicked while it flew away and i tried to get control over the drone by pushing the sticks, but it kept going and made a few spins around. I quickly pressed the RTH button and the uncontrolled fly away stopped. I was able to land the drone without crashing, but not i having trust issues?

this is the flight data:

Can someone help me to understand what happend. There was no strong wind, so i don't understand why there is a max power load error.

thanks for helping me out!
 
Look like you had a fair few compass errors
Was the home point set before take off and why was the battery only at 41% ?
 
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This was most probably nothing else then a take off from a magnetic interfered area ... If you have the possibility try to post up the DAT log from this flight ... Here were to find it on your mobile device --> Flight log retrieval and analysis guide (read under point 3 & Mobile device DAT files (DJI GO 4 & DJI Fly)

A nice "toilet bowl" shaped uncontrollable flight path (see explanation below the pic) with obvious error flags in the beginning.

1582892217446.png

The thing with magnetic interference already at power up of the drone is that the IMU sets the YAW equal to the magYaw (compass) then... everything seems fine as long as you remain in that same strong interference, IMU & compass agrees. This potential upcoming catastrophe can be seen if you look at the drone icon on the map in the app ... it's heading will not align with reality.

Taking of in this situation will be fine to start with usually, as long you are in the interference ... but once out of it the compass correct itself, but not the IMU. This means a disagreement in the information regarding the AC heading direction to the flight controller ... the drone suddenly doesn't know in which direction it points. Then something effects the drone so it need to counteract, wind for instance ... now lost heading wise, the drone spin up/down motors to correct the position but fail to complete the action due to not knowing any direction. This leads to a kind of a snowball effect, the position corrections doesn't succeed so it rev up motors even more still in wrong direction, loses position even more ... & so on.

The flight path in these cases look like circling down a toilet bowl with an increasing speed, usually uncontrollable, eventually ending up in a crash.

You can't calibrate your compass out from this issue & think you can avoid this Yaw/magYaw disagreement. The calibration just teaches the compass to consider the magnetic interference from it's own internal components.

If you get a notice to calibrate your compass always move away to another take off location well separated from the first well away from all magnetic objects ... if several locations tried out then calibrate, check then the drone icon on the map in the app & make sure so it aligns with reality.
 
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Hello,

I'm new to this forum, so a quick introduction. My name is Raymon and i am a proud owner of a Mavic Mini.
Today i was flying in Red Rock Canyon (Near Las Vegas) and i almost crashed my Mavic Mini. Shortly after take off my drone flew away in high speed (S mode was active). My Drone was heading to a mountain with high speed while i was not touching the controls. I panicked while it flew away and i tried to get control over the drone by pushing the sticks, but it kept going and made a few spins around. I quickly pressed the RTH button and the uncontrolled fly away stopped. I was able to land the drone without crashing, but not i having trust issues?

this is the flight data:

Can someone help me to understand what happend. There was no strong wind, so i don't understand why there is a max power load error.

thanks for helping me out!

Do you happen to recall which direction the aircraft was pointing on the ground before takeoff?
 
Thank you guys! I'm not able to post a flight log because i am on a holiday, so don't have a computer.
So i also think it was a compass error. I set the homepoint correctly when i started the flight. The RTH button saved my drone from crashing, because after pushing this button the uncontrolled spin stopped.
I flew with 41% battery because i just wanted to make a circle quickshot. I was not planning to do a long flight. I am on a roadtrip so sometimes it's hard to recharge the battery after each flight.

anyway i will be more careful from now on, i am a beginner, so this is was a good lesson. Thanks for the answers.
 
Thank you guys! I'm not able to post a flight log because i am on a holiday, so don't have a computer.
So i also think it was a compass error. I set the homepoint correctly when i started the flight. The RTH button saved my drone from crashing, because after pushing this button the uncontrolled spin stopped.
I flew with 41% battery because i just wanted to make a circle quickshot. I was not planning to do a long flight. I am on a roadtrip so sometimes it's hard to recharge the battery after each flight.

anyway i will be more careful from now on, i am a beginner, so this is was a good lesson. Thanks for the answers.

Actually the RTH button didn't fix the problem - the uncontrolled flight had already stopped before you hit it. Something else was happening here.
 
Actually the RTH button didn't fix the problem - the uncontrolled flight had already stopped before you hit it. Something else was happening here.
Mmm ... just a theory.

Is it possible that when AC spiraled away & ... down, it got into the same interference as during power on, Yaw/magYaw agreed again (but had wrong heading of course) but enough for the RTH to manage to get the AC home?

1582904209601.png
 
Mmm ... just a theory.

Is it possible that when AC spiraled away & ... down, it got into the same interference as during power on, Yaw/magYaw agreed again (but had wrong heading of course) but enough for the RTH to manage to get the AC home?

View attachment 95312

The data don't support that hypothesis, for a few of reasons. Firstly, the aircraft was still quite high when the problem vanished. Secondly, it later ascended even higher without the problem returning, at least to the same extent. Thirdly, IMU and compass yaw agreeing is necessary but not sufficient for effective RTH navigation - it also has to be correct since it has to fly the required heading based on the location of the home point.

Delta_V.png
 
Pretty clean flight area from the aerial view. Wonder if his vehicle was parked close by?
 
The data don't support that hypothesis, for a few of reasons. Firstly, the aircraft was still quite high when the problem vanished. Secondly, it later ascended even higher without the problem returning, at least to the same extent. Thirdly, IMU and compass yaw agreeing is necessary but not sufficient for effective RTH navigation - it also has to be correct since it has to fly the required heading based on the location of the home point.

View attachment 95316
I've seen this happen, twice I think (connected to being able to RTH). Can only find one of them again ... but that was also a start in magnetic interference followed by the toilet bowl effect, then RTH & it managed to go back.

Here it is ...

Mavic Mini out of control - saved by RTH
 
I've seen this happen, twice I think (connected to being able to RTH). Can only find one of them again ... but that was also a start in magnetic interference followed by the toilet bowl effect, then RTH & it managed to go back.

Here it is ...

Mavic Mini out of control - saved by RTH

I hadn't seen that thread before. However, it turns out that the successful RTH was pure chance - several errors cancelled out. And it was not a magnetically distorted launch site - it was a faulty compass. I've posted the explanation in that thread.
 
Pretty clean flight area from the aerial view. Wonder if his vehicle was parked close by?

My car was parked 100m away. I launched the drone in the middle of the nature, without metal nearby.
Would my smartwatch be a problem? Connected trough bluetooth to my smartphone that also is connected to my joystick.

Anyway.. the best explanation for this incident is the compass error i think.
 
I fly near that area nearly every week (same mountain range). Magnetism even interferes with my M2P . . . I'm not a geologist but I believe those mountains have a high metal content.
 
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My car was parked 100m away. I launched the drone in the middle of the nature, without metal nearby.
Would my smartwatch be a problem? Connected trough bluetooth to my smartphone that also is connected to my joystick.

Anyway.. the best explanation for this incident is the compass error i think.

It's probably a yaw error that caused the problem, but I don't think it's the usual compass error due to a magnetically distorted launch location. But without the DAT file there is no way to be certain.
 
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It's probably a yaw error that caused the problem, but I don't think it's the usual compass error due to a magnetically distorted launch location. But without the DAT file there is no way to be certain.

Next thursday i will fly back to my home in the Netherlands. Then i am able to retrieve the dat file from my mavic mini.

My answers to the other questions: I will remove my smartwatch and turn off bluetooth next time when i start flying, just to be sure. And no i didnt turn on the drone in the back of my car. I switched it on close to the launching area.
 
... retrieve the dat file from my mavic mini.

...I will remove my smartwatch and turn off bluetooth ...

Just to be clear about the DAT log ... the log we need isn't in your Mini, it's in your mobile device. They are under both iOS and Android in a subfolder, MCDatFlightRecords, in the folder that contains the TXT logs.

Then regarding your smart watch ... yeah, it's wise to take that of completely, perhaps not primarily for not disturbing your AC ... but instead to not disturb your RC as the stick inputs are registered by means of magnetism. So wearing electronics or large metal objects near the RC sticks can create unwanted stick inputs.
 
I fly near that area nearly every week (same mountain range). Magnetism even interferes with my M2P . . . I'm not a geologist but I believe those mountains have a high metal content.

Yeah ... it's much more that can be magnetic then what meets the eye. Almost all mobile devices that we use to fly with have a compass module built in, easy to install an app showing a regular compass and move the mobile over the take off spot before setting thing's up to see if it's getting upset.

Then as I wrote earlier, check the heading of the AC icon on the map in the app ... if not align to reality, don't take off.
 
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I found the DAT file on my android phone. See the attachment.
 

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  • DJIFlightRecord_2020-02-27_[09-56-54].txt
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