Mavic 3 Cine hit a tree

[mikeol999]

G’day

My Mavic 3 started to behave strange today. It would not hover in one place and it would keep drifting at the same altitude without me touching the controllers. So, I tried to bring it home. However, it took off with increasing speed and fly over my head and into a tree. DJI Support say that I can raise a warranty request or Care Express. But, which is best? And, is there a way of finding out whether the drone had a problem, or it was just me doing something dumb?

Any thoughts?

Mike

 

[Brockrock]

The only time I experienced what you describe was when I took off with my Phantom 4 years ago from the roof of my car. Several warnings then popped up while airborne regarding magnetic disturbance, and although I did get it down and safe, it only responded normally to vertical control, and any other input caused random movement and drifting. I would be interested in your takeoff environment, and others here can do a pretty good job deciphering your flight logs if you upload them.

 

[Yorkshire_Pud]

If you go to the website

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

and follow the instructions lower down the page, you should be able to retrieve the appropriate flight log. If so upload the log to that website and post the resulting URL here.
Some one will probably have a look at the log for you.

 

[Meta4]

is there a way of finding out whether the drone had a problem, or it was just me doing something dumb?

It sounds like another case of a yaw error.
Post your flight data which will confirm whether that is the case and you'll be able to learn what happened and how to prevent it happening again.

What was the surface you launch from?

 

[mikeol999]

The only time I experienced what you describe was when I took off with my Phantom 4 years ago from the roof of my car. Several warnings then popped up while airborne regarding magnetic disturbance, and although I did get it down and safe, it only responded normally to vertical control, and any other input caused random movement and drifting. I would be interested in your takeoff environment, and others here can do a pretty good job deciphering your flight logs if you upload them.

You could be right about interference. GPS was not working and there was a strange message about altitude that I didn't pay too much attention to as I was only 15-20 ft off the ground trying to get some photos. This was the location: St Georges Lake · St Georges Lake Rd, Creswick VIC 3363, Australia

I will upload my flight logs, but I am having trouble getting them from the drone or my RC Pro.

 

[mikeol999]

If you go to the website

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

and follow the instructions lower down the page, you should be able to retrieve the appropriate flight log. If so upload the log to that website and post the resulting URL here.
Some one will probably have a look at the log for you.

I took a look at the instructions, without much luck. I use an RC Pro as my controller. On that device the folders are empty under DJI Fly. When I power up the drone, I can see the flight logs. The option to upload them to the cloud fails. In the Black Box Data is a list of all the files, both drone and RC Pro, which I think I can download to a folder on the RC Pro. But, I am not able to get them from that device to my Mac. I don't have an SD card and bluetooth transfer does not seem to work......... I might have to give DJI Support a call

 

[MAvic_South_Oz]

I might have to give DJI Support a call

Try and get the txt log yourself and post up that or the phantomhelp (or Airdata) link.
If you leave it to DJI, they tend to skim things and usually go with pilot error, or just let pilots use their care refresh (sometimes when it should / could be a warranty issue).

Analysis here will soon show any anomalies with either, and you can be forearmed with the knowledge it was or wasn't pilot error.
It does seem like a classic yaw error, which would be pilot error, but there is only one way to find out, and that's here (DJI won't usually tell you).

Oh, and welcome to the forum, not a positive first post, but you found a great resource here.

 

[Meta4]

I took a look at the instructions, without much luck. I use an RC Pro as my controller. On that device the folders are empty under DJI Fly. When I power up the drone, I can see the flight logs. The option to upload them to the cloud fails. In the Black Box Data is a list of all the files, both drone and RC Pro, which I think I can download to a folder on the RC Pro. But, I am not able to get them from that device to my Mac. I don't have an SD card and bluetooth transfer does not seem to work......... I might have to give DJI Support a call

Mike ... I might be able to help.
I sent you a message.

 

[Meta4]

I had a look at Mike's data and found that the issue was a yaw error.
The drone was launched from a reinforced concrete surface which deflected the compass at startup.
The gyro sensor took it's directional reference from the compass and when the drone climbed away from the launch point, the compass data went back to normal, but now providing directional data that conflicted with the gyro data.
After a while the flight controller stopped using GPS data which left the drone in atti mode.
Eventually the drone started flying uncontrollably and hit a tree.

 

[mikeol999]

I had a look at Mike's data and found that the issue was a yaw error.
The drone was launched from a reinforced concrete surface which deflected teh compass at startup.
The gyro sensor took it's directional reference from the compass and when the drone climbed away from the launch point, the compass data went back to normal, but now providing directional data that conflicted with the gyro data.
After a while the flight controller stopped using GPS data which left the drone in atti mode.
Eventually the drone started flying uncontrollably and hit a tree.

Thank you so much for your assistance. Let’s hope DJI see it as a warranty claim and give me a new drone!!

 

[MAvic_South_Oz]

Let’s hope DJI see it as a warranty claim and give me a new drone!!

You never know !
Though yaw error due is down to lack of pilot pre flight check (ensure map arrow orientation matches that of drone on the ground).
But good luck, they might just overlook something they should pick up.

 

[Yorkshire_Pud]

Thank you so much for your assistance. Let’s hope DJI see it as a warranty claim and give me a new drone!!

Could one of you share the procedure for retrieving the logs from the RC Pro? Others might find it useful someday.

 

[Meta4]

Could one of you share the procedure for retrieving the logs from the RC Pro? Others might find it useful someday.

It's pretty straightforward.
Just connect it to a (non-Apple) computer and the .txt files are in Android\data\dji.go.v5\files\FlightRecord

 

[Octisurfer]

In macOS you need a little helper tool like Android File Transfer

 

[Ralph thompson]

Surely this is not a warranty claim, there should have been a compass error warning before takeoff (had this situation many times, and would never take off with a compass error). I expect DJs will honour the CARE program. A good procedure to check all is normal at 10' altitude, just after liftoff, check all control movements.

 

[Meta4]

Surly this is not a warranty claim, there should have been a compass error warning before takeoff (had this situation many times, and would never takeoff with a compass error)

The compass warns of magnetic interference if the magnetic field is stronger than the earth's normal magnetic field.
The problem happens when the magnetic influence is not stronger, but is strong enough to deflect the compass sensor causing it to give false directional information to the gyro sensor at startup.

 

[Ralph thompson]

Maybe didn’t express my thoughts very well.
I don’t think compass errors happen very often in flight unless the error was there on the ground before takeoff. You may not have noticed or heard the warning before takeoff but when your in flight, the effect becomes evident because the controller gets confused with contradictory information from the compass, IMU and GPS and it switches to ATTI mode. And in my situation, many years ago with a much more primitive drone, the controller kept deciding it had fixed the problem only to switch back to ATTI a few seconds later. RTH didn’t work, not because of a lack of visible satellites but the controller was no longer using inputs from GPS or the compass.

 

[Meta4]

Maybe didn’t express my thoughts very well.
I don’t think compass errors happen very often in flight unless the error was there on the ground before takeoff. You may not have noticed or heard the warning before takeoff

This incident was not a simple compass error and there was no warning before launching because the magnetic influence was not strong enough to set off a compass warning.
It was not my flight, I just analyzed the flight data to find out what actually happened.

 

[MAvic_South_Oz]

You may not have noticed or heard the warning before takeoff but when your in flight, the effect becomes evident because the controller gets confused with contradictory information from the compass, IMU and GPS and it switches to ATTI mode.

This is why a pilot should check drone arrow orientation on the map, to the actual drone orientation on the ground before take off (when GPS mode is active), and why the lady always says "Home point recorded, please check it on the map."

Having the low magnetic influence causes this interference (and not give any warning).
It doesn't put the drone into atti mode, it just causes the drone to fly off whiele attempting to adjust corrections, totally the wrong way, usually a very fast path, no control, generally until signal is lost, or a crash happens.
A true flyoff but totally unavoidable.

I have read that it can correct itself in a short time in the air, one or two cases I think in the crash section threads over the years . . . but usually this doesn't happen fast enough.

If the map arrow and ground direction are different, all you need to do is shut down, move the drone a little to a new take off point, and try start up again.
This usually fixes the issue.

 

[mikeol999]

Maybe didn’t express my thoughts very well.
I don’t think compass errors happen very often in flight unless the error was there on the ground before takeoff. You may not have noticed or heard the warning before takeoff but when your in flight, the effect becomes evident because the controller gets confused with contradictory information from the compass, IMU and GPS and it switches to ATTI mode. And in my situation, many years ago with a much more primitive drone, the controller kept deciding it had fixed the problem only to switch back to ATTI a few seconds later. RTH didn’t work, not because of a lack of visible satellites but the controller was no longer using inputs from GPS or the compass.

It seemed fine to me when I took off. I was taking some photos and moving around ok. But, it then came up with a warning that I thought said Altitude Mode. I now realise it was Attitude mode. When you are flying, you don't get much time to read the messages as they come up and then disappear while you are trying to focus on where your are etc. My issue is - how am I supposed to know what Attitude mode is? It is not explained anywhere by DJI and does not come up in a search on the DJI website. Until discussing the crash on this forum, I had never heard of it before or knew it was actually important. Also, DJI does not instruct you to check direction on map or satellites or anything like that in their pre-flight check instructions for the Mavic 3.