Mavic Mini flyaway

[hendawg]

Hello all!

I am new to this forum and drone flying in general, so please excuse any ignorance on my part. I bought a Mavic mini a few weeks ago, and had flown it a few times. With only 45 minutes of flight time total, three days into owning it, it flewaway. I was stunned when it happened, as I had been following all the checklists and guidelines, and everything seemed perfectly fine, including the sat GPS connection. It suddenly took of in one direction and managed to hit a top speed of 75 MPH! There was also almost no wind, so I can't imagine that was the cause. I have been in touch with DJI support and have given them the flight data, but they have been very slow to get in touch with me. I have the refresh warranty, but I am struggling to find the drone. Its last recording location was at the intersection of four properties in a wooded area, so I have been bothering all my neighbors and I don't think I can do that much more.

I was hoping this forum could help me figure out what went wrong and potentially help me with my case with DJI, and to find out where it could be.

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Thank you!

 

[dirkclod]

75mph ? @sar104 Where are youuuuu..

 

[rafare]

Seems like some type of GPS failure, the GPS started throwing NoMatch errors Just after take-off. There's a bunch of errors related to GPS and Compass in the logs. I'm sure the guys here will have more info about that.

I would say the Mini is stuck to this big tree, appears to be very dense, considering the Mini is so light, probably it is still up there. Hard to recover, but anyway, worth a look.

 

[hendawg]

Seems like some type of GPS failure, the GPS started throwing NoMatch errors Just after take-off. There's a bunch of errors related to GPS and Compass in the logs. I'm sure the guys here will have more info about that.

I would say the Mini is stuck to this big tree, appears to be very dense, considering the Mini is so light, probably it is still up there. Hard to recover, but anyway, worth a look.

View attachment 108917

Thank you! After stomping around in some folks yards for a couple hours I figured its probably stuck up in one of those trees. As for the GPS error, that's interesting. When I took off I had somewhere between 8-10 satellites, and a minute after it went up to 11 or so, so I didn't think there was a problem. I don't recall seeing any error messages before taking off, as I wouldn't take off if that were the case. I went up just over my house to take a picture and then it took off.

 

[sar104]

Unfortunately you powered up the aircraft in a location with local magnetic interference, resulting in the IMU heading being initialized incorrectly. It was out by around 155° at takeoff, which led to the uncontrolled flight:



As has been repeated many times, you need to ensure before takeoff that the aircraft orientation arrow on the map is pointing in the same direction as the aircraft on the ground. It's the only definitive check that the IMU has been correctly initialized.

Seems like some type of GPS failure, the GPS started throwing NoMatch errors Just after take-off. There's a bunch of errors related to GPS and Compass in the logs. I'm sure the guys here will have more info about that.

It was a compass error, not a GPS problem.

 

[hendawg]

Unfortunately you powered up the aircraft in a location with local magnetic interference, resulting in the IMU heading being initialized incorrectly. It was out by around 155° at takeoff, which led to the uncontrolled flight:

View attachment 108918

As has been repeated many times, you need to ensure before takeoff that the aircraft orientation arrow on the map is pointing in the same direction as the aircraft on the ground. It's the only definitive check that the IMU has been correctly initialized.


It was a compass error, not a GPS problem.

Okay. What exactly does local magnetic interference mean? Is that orientation check in the preflight checklist that DJI gives? Because I was unaware that is something necessary for proper flight.

Thanks.

 

[sar104]

Okay. What exactly does local magnetic interference mean? Is that orientation check in the preflight checklist that DJI gives? Because I was unaware that is something necessary for proper flight.

Thanks.

Local interference can be very short range - down to a few centimeters if you power up the aircraft close to rebar in concrete, for example. All it takes is something with a strong enough magnetic field to distort the compass reading at power up.

And no - it's not mentioned anywhere in any DJI manuals or guidance - even though they are perfectly well aware that it is the major cause of uncontrolled flight. It appears that they think it is too complicated to expect the average user to do it. They may be correct, but it is the only guarantee of stable flight.

 

[hendawg]

Local interference can be very short range - down to a few centimeters if you power up the aircraft close to rebar in concrete, for example. All it takes is something with a strong enough magnetic field to distort the compass reading at power up.

And no - it's not mentioned anywhere in any DJI manuals or guidance - even though they are perfectly well aware that it is the major cause of uncontrolled flight. It appears that they think it is too complicated to expect the average user to do it. They may be correct, but it is the only guarantee of stable flight.

Thank you so much for this info. It's good to know this for the future. It is unfortunate DJI doesn't explain something that is seemingly very important for proper flight.

 

[sar104]

Thank you so much for this info. It's good to know this for the future. It is unfortunate DJI doesn't explain something that is seemingly very important for proper flight.

Agreed. And in terms of location - yes - it's in those trees.

 

[sar104]

In case it helps with the search, it was stuck around 60 ft up when the motors shut down.

 

[hendawg]

In case it helps with the search, it was stuck around 60 ft up when the motors shut down.

Thanks. I have a feeling I won't be retrieving it, as I can't really climb up the tree . Hopefully, it will come down sometime and my neighbor will find it and return it.

 

[shaneb50]

I had the same problem with my drone on the Mavic Mini.everything checked out alright,but as it took off.it went out of control and crashed
Luckily it was ok no damage

 

[SpitFire]

Question is How to avoid or prevent this from happening to other pilots? When I am in a new area, never flown before, I watch my instruments, watch the drone, take it up in 25 feet increments, and watch how it reacts. Have had it happen near a radio tower, tower was hidden by trees. Drone was 50 feet up and acting strangely. Brought down manually and found another place to fly.

 

[sar104]

Question is How to avoid or prevent this from happening to other pilots? When I am in a new area, never flown before, I watch my instruments, watch the drone, take it up in 25 feet increments, and watch how it reacts. Have had it happen near a radio tower, tower was hidden by trees. Drone was 50 feet up and acting strangely. Brought down manually and found another place to fly.

The simply way to prevent it is described in post #5.

 

[DrizzyDrones]

so in a case like this where compass issue from powering up in a bad location does dji reconize this as pilot error or because it is not explained is it considered hardware malfunction...

also honestly i find the orientation arrow cab be off when taking off but it fixes itself after a short hover a few meters up and out... i seen a Video other day on this forum where they put a magnet on the mini and it threw orientation arrow wayy off but fixed itself even with magnet left on during flight

 

[RichR]

It sort of is pilot error, as the manual does say to avoid areas of magnetic disturbance (eg buildings, electrical devices etc) when choosing a takeoff location. In the same way as if the owner of a light aircraft tried to take off from a grass runway that's got sheep in the same field. You'll probably get away with it most of the time, but it's a risk that you should be aware of and avoid taking.

However - they do know that they're selling to people who don't necessarily read manuals, take the time to understand how flight works or follow well accepted radio controlled model procedures such as pre-flight checks. So if you're polite they're quite likely to say 'well it wasn't the best place to take off, but we'll honour the refresh insurance as you did everything else right'

 

[sar104]

so in a case like this where compass issue from powering up in a bad location does dji reconize this as pilot error or because it is not explained is it considered hardware malfunction...

also honestly i find the orientation arrow cab be off when taking off but it fixes itself after a short hover a few meters up and out... i seen a Video other day on this forum where they put a magnet on the mini and it threw orientation arrow wayy off but fixed itself even with magnet left on during flight

It's not a hardware malfunction. And while the Mini and the M2 both have a limited mechanism to fix an incorrectly initialized IMU it should never be relied on. If you choose to continue to ignore it after all the warnings on this forum then your aircraft will inevitably have problems.

If you are interested in the correction mechanism, and its limitations, I explained it in this thread:

Compass error demonstration

Ok my apologies, I don’t own a Mavic but I know how my phantom standard and i1 reacted in these exact same locations, pix below. With a compass error. I was totally wrong for flying in these areas but I clearly remember how my drones reacted after take off. I had to walk out of the block to keep...

mavicpilots.com

 

[DrizzyDrones]

It's not a hardware malfunction. And while the Mini and the M2 both have a limited mechanism to fix an incorrectly initialized IMU it should never be relied on. If you choose to continue to ignore it after all the warnings on this forum then your aircraft will inevitably have problems.

If you are interested in the correction mechanism, and its limitations, I explained it in this thread:

Compass error demonstration

Ok my apologies, I don’t own a Mavic but I know how my phantom standard and i1 reacted in these exact same locations, pix below. With a compass error. I was totally wrong for flying in these areas but I clearly remember how my drones reacted after take off. I had to walk out of the block to keep...

mavicpilots.com

I would never risk it i take the knowledge of the people like you and others seriously and I know that it has prevented and avoided bad situations so I thank you for that I was just curious as the consensus on the self fixing thing. I do find sometimes orientation seems off when close but send it out a little and it corrects wouldnt ever risk flying if it is off

 

[kidroc]

Thank you so much for this info. It's good to know this for the future. It is unfortunate DJI doesn't explain something that is seemingly very important for proper flight.

To be fare I don’t think any of the big drone companies mention anything about it either not just DJI...

 

[RichR]

To be fare I don’t think any of the big drone companies mention anything about it either not just DJI...

They do tell you fairly clearly in the manual that certain places may affect the compass and GPS system. But I guess they don't say what the effects would be if the compass wasn't accurate.


There are similar instructions in the manuals for my Hubsan and Cheerson drones, though again it doesn't say what could happen if the compass isn't reliable as a result.