Hi,

Yesterday I flew with my magic 2 pro for the third time. I had some magnetic interferences furst, after calibration it seemed to be ok. I started the mavic and had it approx 20 metres above Home when all if the sudden I lost the connection to it! It stood there for a minute and then started to flu by its own! Horrible! I wanted to use the return to hi.e button but it was greyed out. The drone then came down and stopped 2 meters above me. I had to catch it from underneath which made it very angry (it was fighting against me - as if i was a superstrong wind). After a minute it stoped the motors. Relief...

1. What had happened? Why and how can it lose connection to the remote?

2. How can I stop the drone if that happens again?

Thanks!

Hi, sorry to hear about that. May I know if you get an error message before the signal loss? Please kindly re-link your remote controller to your aircraft. Thank you.

First, two things:
1) If you get magnetic interference warnings - move to a different take off spot.
2) If you are going to re-calibrate compass - go to a location that has nothing around it in any direction for at least 10-meters.  Make sure there is nothing overhead like power lines, and there are no buried power lines or metal pipes under area.

Did you try RTH (Return Home) button on the RC?  
From what you are describing, the Remote Control lost connection with your SmartDevice running GO-4 (greyed out RTH button).

If you want to look at amount of Magnetic Interference to compass here is how:

Mavic Pro has two compasses.  Believe Mavic 2 Pro only has one compass, like Mavic Air.

Each compass has three axis (XYZ) magnetic field strength detectors.
You can view the individual compass's sensors combined (XYZ axis) magnetic field interference by doing following steps:

* Under main menu of GO-4 App - in middle at Top of Screen - Tap on QuadCopter Icon
* At bottom of MC Settings screen - Tap on Adance Settings
* At bottom of Advance Settings screen - Tap on Sensor State
* At top of Sensor State screen - Tap on Compass

Below Interference, you should see two compasses for Mavic Pro, and one compass for Mavic 2 Pro and Mavic Air
Blue dot next to Compass (1 or 2) indicates which one is being used in case of Mavic Pro.

When you are in an area, say large field (100-foot x 100-foot) with no high voltage lines overhead, metal pipes or buried underground power...
With a correctly calibrated compass - Both bars should be "Green'' and short in length.  Neither of bars should be ''Yellow'' or ''Red''.

Below is an example of Compass sub-menu under Sensor State screen:



In picture, both compasses are picking up slight amount of Magnetic Interference.
Compass #1 is picking up more interference because of how Mavic Pro was situated over narrow strip of sheet metal at the time.

1. What had happened?

You need to upload your FlightLog file to Phantom Helps Log viewer.  Link: http://www.phantomhelp.com/LogViewer/Upload

Once uploaded and processed:
You can look at information from output there and/or download CSV (comma  seperated values) file.  Viewable in your favorite SpreadSheet Program  (Excel).
If you want help with FlightLog, post back the Web-Link (from top of your Web brower) of output webpage.

Another option is to download JBSpark's FRAP program ( ) to look at your FlightLogs.  https://forum.dji.com/thread-145649-1-1.html

DJI Natalia Posted at 2018-9-22 11:45
Hi, sorry to hear about that. May I know if you get an error message before the signal loss? Please kindly re-link your remote controller to your aircraft. Thank you.

No. Relinking is not be the oriblem when the mavic is back on earth. So what had happenrd thst it lost connection?

HedgeTrimmer Posted at 2018-9-22 12:08
1. What had happened?

You need to upload your FlightLog file to Phantom Helps Log viewer.  Link: http://www.phantomhelp.com/LogViewer/Upload

Thanks! I just tried to upload rhe file but it didn't work. I'll check on that later.

HedgeTrimmer Posted at 2018-9-22 12:08
1. What had happened?

You need to upload your FlightLog file to Phantom Helps Log viewer.  Link: http://www.phantomhelp.com/LogViewer/Upload

Here it is:
http://www.phantomhelp.com/LogViewer/2K5KYDD6XVYAX3XXISMP/

I hope that this is resolved soon. This does not help you but prior to my crash I too had a message re magnetic interference that did not make it to the logs. In my case I was performing a helix shot and the M2P started to descend onto the top of a stadium light.

Packer Backer Posted at 2018-9-24 03:33
I hope that this is resolved soon. This does not help you but prior to my crash I too had a message re magnetic interference that did not make it to the logs. In my case I was performing a helix shot and the M2P started to descend onto the top of a stadium light.

I am flying for several years now, and this was the first time that horrible stuff like that happened to me. Never happened with mavic 1 or  my phantom.  If it was the app then it´s an android problem: I usually only use the iphone it was the 2nd time I used the app with my Samsung S9. But it worked the week before!

I will get myself the crystalsky-Monitor when it´s Mavic 2 compatible.   

Personally I think that DJI app works much more stable on iOS.
Crystal sky is android based.
Also that’s why I think DJI is postponing the release of the android base controller with a build in screen, it has many bugs and glitches still.

Fly safely
Alex

Try an Apple device

PhilippHa Posted at 2018-9-24 03:52
I am flying for several years now, and this was the first time that horrible stuff like that happened to me. Never happened with mavic 1 or  my phantom.  If it was the app then it´s an android problem: I usually only use the iphone it was the 2nd time I used the app with my Samsung S9. But it worked the week before!

I will get myself the crystalsky-Monitor when it´s Mavic 2 compatible.

Its Compatible now.

If you lost connection and had no control that is RC to AC. Phone or cable probably not an issue. I have had this same thing happen several times with Mavic 2 pro multiple phones and cables. The RC disconnects from AC even a few feet away.

PhilippHa Posted at 2018-9-24 03:28
Here it is:
http://www.phantomhelp.com/LogViewer/2K5KYDD6XVYAX3XXISMP/

Brief look, nothing to me stood out.  Perhaps others here can take a look too.
I will try to look at verbose CSV to see if there is anything there.

Check Under the Aircraft status screen  "RADIO CHANNEL QUALITY" should say GOOD not .........POOR........ "strong interference fly with caution"

Raiderfan Posted at 2018-9-24 10:05
Check Under the Aircraft status screen  "RADIO CHANNEL QUALITY" should say GOOD not .........POOR........ "strong interference fly with caution"

It had been all good...

bjr981s Posted at 2018-9-24 05:56
Its Compatible now.

It is?
What kind of issues had there been with crystalsky in the past?

Looking at your log, it doesn’t show any problems with compass, it also doesn’t report lost connection, but it should have, basically you lost signal and your drone RTH , I’m not sure and it’s impossible to say why, in that situation you are best to try switching off RC then back on to see if it regains signal, it will also trigger RTH immediately , your log stops recording so there is very little there to know why it just hovered, but if it sees that it’s not safe to land it will hover, until it reaches critical battery and just force land.

hallmark007 Posted at 2018-9-24 15:10
Looking at your log, it doesn’t show any problems with compass, it also doesn’t report lost connection, but it should have, basically you lost signal and your drone RTH , I’m not sure and it’s impossible to say why, in that situation you are best to try switching off RC then back on to see if it regains signal, it will also trigger RTH immediately , your log stops recording so there is very little there to know why it just hovered, but if it sees that it’s not safe to land it will hover, until it reaches critical battery and just force land.

Thank you for your answer - and your tips what to do if it happens again.
Hovering: it could have landed there, paved road.
Very strange, indeed.

PhilippHa Posted at 2018-9-24 03:28
Here it is:
http://www.phantomhelp.com/LogViewer/2K5KYDD6XVYAX3XXISMP/

Looks like Remote Controller disconnected from SmartDevice running GO-4.  Resulting in FlightLog on GO-4 abruptly ending.  Which would go along with RTH button being Grayed out on GO-4 App.

Perhaps FlightLog on Mavic Pro would show whether RC and Mavic Pro were still communicating?

PhilippHa Posted at 2018-9-24 03:28
Here it is:
http://www.phantomhelp.com/LogViewer/2K5KYDD6XVYAX3XXISMP/

Sorry for your accident. Can You please recheck, that the file for flight record is correct one? This one looks innocent and i just think maybe it is from another flight

nixuspix Posted at 2018-9-24 22:46
Sorry for your accident. Can You please recheck, that the file for flight record is correct one? This one looks innocent and i just think maybe it is from another flight

It is. There are only 4, as thars all the flights so far.

I had this happen multiple times with android devices that are not compatible when using the side USB. the controller would crash. This happened with all mavic drones that I have flown (and it's a lot) if you want to use a non supported android device, is the buttom USB avaible on the mavic controllers and stay away from the side USB. Also be prepaired to restart the crashed DJI GO app a lot of times ;)

nivong Posted at 2018-9-25 01:19
I had this happen multiple times with android devices that are not compatible when using the side USB. the controller would crash. This happened with all mavic drones that I have flown (and it's a lot) if you want to use a non supported android device, is the buttom USB avaible on the mavic controllers and stay away from the side USB. Also be prepaired to restart the crashed DJI GO app a lot of times ;)

Are you using a Apple mobile device now ?

Kingram Posted at 2018-9-25 11:48
Are you using a Apple mobile device now ?

Depends on what I have in my pocket. Or my iPhone 6, Oneplus 3 or my iPad mini 3.  I am not using 1 device. What I use the most is the RE goggles

PhilippHa Posted at 2018-9-24 23:38
It is. There are only 4, as thars all the flights so far.

To start eliminating possible causes of disconnect.
Replace USB cable between RC and your SmartDevice.

HedgeTrimmer Posted at 2018-9-25 15:34
To start eliminating possible causes of disconnect.
Replace USB cable between RC and your SmartDevice.

It is and has been the Android app! I tested the mavic with my iphone- no problems whatsoever! At the very same spot i plugged in the Samsung s9, and opened the app.it didn't connect, a window opened (that never opens in iOS): set up connection. At this point the RC already warned: magnetic interferences.
I unplugged the Samsung and wanted to see if the rc had connection to the drone, which it had not!

PhilippHa Posted at 2018-9-26 11:50
It is and has been the Android app! I tested the mavic with my iphone- no problems whatsoever! At the very same spot i plugged in the Samsung s9, and opened the app.it didn't connect, a window opened (that never opens in iOS): set up connection. At this point the RC already warned: magnetic interferences.
I unplugged the Samsung and wanted to see if the rc had connection to the drone, which it had not!

Good information.  Nice work!

HedgeTrimmer Posted at 2018-9-26 13:04
Good information.  Nice work!

Strange stuff. At least this time I could do some filming;-)

https://vimeo.com/292012001