Mavic Mini Fly Away?

[Marcos Perez]

Hello to all.

Last month I took my mavic mini to sea level for the first time. I live at 2800meter above sea level.
In the first flight, everything was ok, until min 4:41. the drone started to fly away, up to over 40mph.
I'm leaving here the link of the log

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

is the mavic mini capable of reaching those speeds?.
The drone crashes on the roof of the building and I get it back, with only a broken leg.. It is on the road again, but I'm kind of scared of flying again, at least until I get to understand what happened.
In the area of the flight is a golf course, and in those days, there where lots of gust of wind, but it was 7am and the wind appear ok in the UAV forecast.
I know I panic when the drone started to go away, press RTH button , and the drone crashed on the building when returning.
I really appreciate is someone can light me about what happened..

Best regards.

 

[boblui]

There was very little wind so the wind is not to be blamed.

At 278 sec into the flight, something went wrong. Right rudder was applied but the craft yawed to the left followed by the craft going into the class "toilet bowl" flight path indicating that the sensing of direction was incorrect. Could be due to IMU problem. If you can upload the .DAT file in the phone, some more insight can be obtained.

 

[Meta4]

In the first flight, everything was ok, until min 4:41. the drone started to fly away, up to over 40mph.

is the mavic mini capable of reaching those speeds?.

The high speed uncontrollable curved flight is characteristic of a yaw error incident caused by powering up the drone in a spot where magnetic interference caused deflection of the compass that's used to initialise the gyro sensor.

Can you describe the spot where you launched from?
What direction was the drone facing at launch time?

 

[Marcos Perez]

I launched the drone from a concrete stairs. Don't remember if the drone were facing to me or to the field at launch. Calibrated the compas before launch, previously the last Flight was in a City 400km distant.

 

[Meta4]

I launched the drone from a concrete stairs.

There's your problem.
The steel reinforcing in the concrete caused the problem.
Launching from reinforced concrete surfaces is just asking for trouble like this.

Calibrated the compass before launch, previously the last Flight was in a City 400km distant.

Calibrating the compass doesn't do anything to fix the problem which was powering up the drone with the compass affected by the invisible steel that was right below it.

 

[boblui]

There's your problem.
The steel reinforcing in the concrete caused the problem.

That could not be the cause. There was not any significant yaw error and the craft was well under control until 278 seconds.

 

[Meta4]

That could not be the cause. There was not any significant yaw error and the craft was well under control until 278 seconds.

We've seen other similar incidents where the issue didn't show till later in the flight.
But the uncontrolled high speed curved path is very distinctive.
It's a yaw error problem and launching from reinforced concrete surfaces is a very common cause of yaw errors.

 

[boblui]

We've seen other similar incidents where the issue didn't show till later in the flight.
But the uncontrolled high speed curved path is very distinctive.
It's a yaw error problem and launching from reinforced concrete surfaces is a very common cause of yaw errors.

Yaw error has no effect only in ATTI mode. In this case there were 18 ~ 19 satellites so if there was any significant yaw error, the craft would go wide immediately.

The lack of yaw error in the early part of the flight is evident by the fact that the orientation of the craft is the same as the direction of movement of the craft when only forward elevator was apply.



This is after yaw error has occurred. The craft was tilted to the right . Hoever it did not move in that direction but backward. The yaw error was about 90 degrees.

 

[Meta4]

This is after yaw error has occurred. The craft was tilted to the right but it did not move in that direction but backward instead. The yaw error was about 90 degrees.

So you are saying it was a yaw error?
I can't tell what you are disagreeing about.

 

[slup]

So you are saying it was a yaw error?
I can't tell what you are disagreeing about.

He's disagreeing about what you write as per below ... this case doesn't follow the usual pattern for magnetic disturbance at power up, the clearest sign is as said, that the initial flight path direction match AC direction & stick position.

The true reason is in the mobile device DAT log ending with FLY055.DAT.

...launching from reinforced concrete surfaces...

 

[Marcos Perez]

I don't know if launching the drone from the concrete will be a strong issue. I use to fly my drone from the roof of my building at leas twice a month (concrete floor) and never happened before.

 

[Meta4]

I don't know if launching the drone from the concrete will be a strong issue. I use to fly my drone from the roof of my building at leas twice a month (concrete floor) and never happened before.

Launching from reinforced concrete surfaces is a very common cause of drone loss.
We see these incidents every week in drone forums.
This explains why (and why it doesn't happen every time).

Avoiding the rebar effect

I would like to make my takeoff and home point on a concrete portion of my driveway. Thinking of using a wooden table to distance my takeoff point from the rebar underneath. How tall should the table be? .... or is this just a wish that should not be pursued at all .... and why?

phantompilots.com

Launching from reinforced concrete surfaces is asking for trouble and should be avoided if you want to fly safely.

 

[Marcos Perez]

Thanks for all your repplys. I have to read and lean a lot more about how yo fly safely my drone..!!!

 

[slup]

Thanks for all your repplys. I have to read and lean a lot more about how yo fly safely my drone..!!!

Yeah, that's good ... even though the incident itself is a disappointing & sad experience, it might feel easier if it comes with some valuable lessons learned.

Powering up the AC in a magnetic disturbed area with following yaw error is unfortunately pretty common & actually easily avoided with a bit of knowledge.

But in your incident here, the signs so far say that it's likely that the yaw error was caused by something else ... if you truly want to know the cause (& possibly further add to your knowledge) you need to provide the DAT log that should be stored in the mobile device you flew with.

The one for this flight ends, as said earlier, with FLY055.DAT. It's stored in a subfolder, MCDatFlightRecords, in the folder that contains the TXT logs.

Attach it then here in a new post ... with that at hand we will have access to all sensor data that isn't included in the TXT log & with that should have a better possibility to circle in the cause.

 

[Marcos Perez]

I only have a fly062.dat file on that phone.

 

[slup]

I only have a fly062.dat file on that phone.

That was unfortunate ... those you attached is only a AC power on (from here the DAT start to record), nothing more. The FLY055.DAT is needed.

That it's gone is probably due to below ...



That the FLY062.DAT was left in the MCDatFlightRecords folder was most probably due to that a TXT log wasn't created (TXT record from motor start) so nothing could be synced to DJI servers.

Then all ends here I'm afraid.

 

[Marcos Perez]

Finally understood why my Mavic Mini crashed:
I get the MM about 100 meters or less from those power lines.. Those are 130 kv.. Didn't notice them until today that I'm watching the pictures.
The drone was repaired an have 10 flights without any issue...
Leason learned the hard way.

 

[Thomas B]

Finally understood why my Mavic Mini crashed:
I get the MM about 100 meters or less from those power lines.. Those are 130 kv.. Didn't notice them until today that I'm watching the pictures.
The drone was repaired an have 10 flights without any issue...
Leason learned the hard way.

View attachment 114907

Glad you figured it out. Love happy endings!

 

[Meta4]

Finally understood why my Mavic Mini crashed:
I get the MM about 100 meters or less from those power lines.. Those are 130 kv.. Didn't notice them until today that I'm watching the pictures.
The drone was repaired an have 10 flights without any issue...
Leason learned the hard way

Those powerlines had no effect on your flight.
The explanation for the issue was given much earlier in this thread.

 

[Hi-Flyer]

That could not be the cause. There was not any significant yaw error and the craft was well under control until 278 seconds.

Launching from reinforced concrete surfaces is a very common cause of drone loss.
We see these incidents every week in drone forums.
This explains why (and why it doesn't happen every time).

Avoiding the rebar effect

I would like to make my takeoff and home point on a concrete portion of my driveway. Thinking of using a wooden table to distance my takeoff point from the rebar underneath. How tall should the table be? .... or is this just a wish that should not be pursued at all .... and why?

phantompilots.com

Launching from reinforced concrete surfaces is asking for trouble and should be avoided if you want to fly safely.

On the MA2 site a few days ago someone posted a nice video in which his MA2 took off from and landed on the bonnet of his car. I asked him about the car's metal influencing the drone's compass, and he said there was no influence: the simple fact is that he took off, flew well, and landed normally. So why should steel rods embedded in concrete cause interference?