Hi!
Today my Mavic for some reason started to fly away on its own and crashed in to some trees.
I had just begun the flight and had ascended to the chosen height when I let go of the sticks, and after a couple of seconds the aircraft started to fly sideways t quite high speed and in a matter of seconds it smashed in to some trees.
No stick input when it started to fly away on its own, and when I saw that it was going to crash I pulled left stick down.

Before the flight I checked the compass interference levels in DJI Go and it was OK. (Hardly visible short green bars), and I had good GPS signal.
However, I must quite often recalibrate the compass due to high interference levels on compass 1 when I power up, so I think it may be some hardware malfunction.
I am very careful not to have any disturbing objects around me when I calibrate the compass, but still I have to recalibrate on almost every power up.

Could it be compass malfunction that caused this crash?

Here is the link to what I belive is the correct log file:
https://www.dropbox.com/s/icg2kb6ltegu3uz/FLY056.DAT?dl=0

Could someone help me analyze log file and maybe see what caused the crash?
Hardware or software malfunction, or something else maybe?

Thanks in advance!

having to recalibrate on almost every power up does not sound correct. I read somewhere once that you should only recalibrate if the app advises you to do so or if you have moved to a far away location. I have not been instructed to recalibrate for months now - that you must do frequent recalibrations sounds like there is an onboard calibration issue.

I had the same thing happen to me July 4th. I have viewed the flight log and it does not show any input from the right joy stick however it took off into my fence right after take off. I have about 250 flights and have become more and more confident but after that I loss some. I only broke a prop got lucky. Any ideas?

There are a couple of guys who understand dat file droneflying is one he might pop in and have a look at it.
Can you upload your log to link below, just click on link and follow instructions and come back here and post link to your logs. You might be able to get a better understanding of what happened.

http://www.phantomhelp.com/LogViewer/Upload/

hallmark007 Posted at 2017-7-6 15:14
There are a couple of guys who understand dat file droneflying is one he might pop in and have a look at it.
Can you upload your log to link below, just click on link and follow instructions and come back here and post link to your logs. You might be able to get a better understanding of what happened.

Thanks for your reply, hallmark007!

I´ve uploaded the flight log (in txt-format) and here is the link to it:
http://www.phantomhelp.com/LogViewer/YXXHUR53T9R7TGPUE6EM/

It shows both "Compass Error" and a "Speed Error".
What do you say, guys
do you thinks this looks like a warranty issue, if I should send the drone to DJI for repair?

MBX Mavic Posted at 2017-7-6 20:15
Thanks for your reply, hallmark007!

I´ve uploaded the flight log (in txt-format) and here is the link to it:

Thans for your log information (above).

It seems clear you had a Compass Error, at least. Perhaps the first thing to try is a Compass Recalibration just before you start your next flight.

If that doesn't go okay perhaps you're idea of sending it in for warranty repair is necessary.

_______________________________________________

Flyer_BFK Posted at 2017-7-6 21:46
Thans for your log information (above).

It seems clear you had a Compass Error, at least. Perhaps the first thing to try is a Compass Recalibration just before you start your next flight.

I had a similar problem

RIGHT STICK COMMANDS FOR BACK AND FORWARD STOPPED WORKING. -- Instead it would 'pan' left and right.                    (and the normal, Mode 2, command for left and right remained the same)

It was working initially in the flight but that it suddenly happen. Hit RTH.

It worked out okay, but I'm new at this, my first RTH and it seems to start out right, from what I've read, but instead of coming towards me (at Home) it took off behind me and I lost sight of the Mavic. -- Gads! -- Miles of sagebrush desert in every direction and not a clue.

But then it appeared, coming from behind me, over my head, started to land. Got the message:
UNSAFE LANDING AREA. - OMG - Well, there were modest rocks around but I wanted it down, keep pressing down and down it landed, a-okay.

From what I've read, re-calibrating the sticks on the RC would be step one. Any other information?

MBX Mavic Posted at 2017-7-6 20:15
Thanks for your reply, hallmark007!

I´ve uploaded the flight log (in txt-format) and here is the link to it:

Looking at this log, it looks like you had big compass problem, it seems that you may have picked up this problem on the ground before take off , this often happens particularly if you take off near any metal objects or rebar concrete.
This compass has an effect on your gps heading like if you push forward compass will take your AC in a different direction so no matter what you would have done it would have been impossible to control your AC. Really your AC should have gone into Atti mode and if it did you may still have had some control, but it looks like that didn't happen.

Will dji offer warranty you would be very lucky, but your dat file will show a lot more regarding if there was a problem with compass and if this is the case , then dji will honour your warranty.

Although this doesn't help you now, before taking off if you check your compass heading which is the little arrow on your map in left hand corner iOS it should be pointing on the same heading as your AC.

I wish you luck my friend.

I have contacted droneflying, he will pop over sometime and have a look at your dat.

Flyer_BFK Posted at 2017-7-6 21:47
I had a similar problem

RIGHT STICK COMMANDS FOR BACK AND FORWARD STOPPED WORKING. -- Instead it would 'pan' left and right.                    (and the normal, Mode 2, command for left and right remained the same)

Yes recalibrate your sticks, regarding compass never calibrate compass unless you are prompted to, if you are on the ground waiting to take off and you get compass interference, just move to another location.
Also a tip when checking things are working correctly before flight.

Start AC
Raise to height 8ft
Hover 30 seconds
Forward 3ft
Back 3ft
Up 3ft
Down 3ft
Left 3ft
Right 3ft
Yaw left Yaw Right
Each time bringing AC back to hover position
If AC returns to good horizontal each time, you will then know you have good IMU good compass and good gps, and your ready to fly, it takes less than 2 minutes.

As a mater of curiosity, could you indicate when your Mavic was manufactured / purchased?  You can go here  and input the serial number to get the manufacture date.

Some of the earlier manufactured drones had some rear motor wiring issues which causes noise in the rear compass at higher motor speeds.

I've looked at the DAT file but I'm seeing some data that I'm not really sure how to interpret, so I'm going to ask BudWalker if he can take a look at it.

I looked at this flight some. As @DroneFlying noted the data shows something odd. You really should ask DJI about this. I don't have a compelling answer.
But, I'll speculate a bit. The flight occurred at the higher latitudes where the geoInclination is 75 degrees. This makes to determing heading from magnetometer data more difficult If the geoInclination were 90 degrees, like at the magnetic north pole, then heading can't be determined from magnetometer data.  In general, there isn't any reason to think that a Mavic wouldn't know it's heading at these latitudes. But a Mavic with marginal X or Y magnetometer would have to struggle a bit more. The fact that you've had to calibrate more than once could be an indicator of a marginal magnetometer. DJI will probably tell you to calibrate the compass, but you've done this. Several times. I suspect you're pretty good at it by now and it won't make much difference.


The odd thing that both DroneFlying and I noticed is that the Mavic thinks that shortly after launch the magnetometers showed there is a slight Yaw error. It's not enough to suspect a geoMagnetically distorted launch site. The response is to rotate CCW as shown by totalGyroZ (green line). But, then it looks like the magnetometer data (red line) is showing a CW rotation. See the attached. The actual CCW rotation is accelerated to compemsate but then the magnetometer data shows a an even faster CW rotation. totalGyroZ is another way to know relative heading changes that is independent of the value that the FC computes for Yaw.

Good luck.

BudWalker Posted at 2017-7-8 14:47
I looked at this flight some. As @DroneFlying noted the data shows something odd. You really should ask DJI about this. I don't have a compelling answer.
But, I'll speculate a bit. The flight occurred at the higher latitudes where the geoInclination is 75 degrees. This makes to determing heading from magnetometer data more difficult If the geoInclination were 90 degrees, like at the magnetic north pole, then heading can't be determined from magnetometer data.  In general, there isn't any reason to think that a Mavic wouldn't know it's heading at these latitudes. But a Mavic with marginal X or Y magnetometer would have to struggle a bit more. The fact that you've had to calibrate more than once could be an indicator of a marginal magnetometer. DJI will probably tell you to calibrate the compass, but you've done this. Several times. I suspect you're pretty good at it by now and it won't make much difference.

Good job Budwalker, do you have an English version lol...

hallmark007 Posted at 2017-7-8 15:38
Good job Budwalker, do you have an English version lol...

Yeah, yeah. Sorry about that. It doesn't matter though since I'm just speculating.

hallmark007 Posted at 2017-7-7 01:25
Yes recalibrate your sticks, regarding compass never calibrate compass unless you are prompted to, if you are on the ground waiting to take off and you get compass interference, just move to another location.
Also a tip when checking things are working correctly before flight.

Thanks. Good solid ideas. Will do.
Your other idea (from a different post) also seemed good: "before taking off if you check your compass heading which is the little arrow on your map in left hand corner iOS it should be pointing on the same heading as your AC."  -- I like this idea a lot because it's a clear check that can be made. Keep flying!