[size=14.6667px]Hey guys and DJI Supports.
[size=14.6667px]

[size=14.6667px]I had a scary flight this morning. I was shooting an Indian Temple Statue in Malaysia. Half way through the flight, DJI GO 4 Apps said "Aircraft Disconnected", I couldn't see anything from my DJI GO 4 Apps.
[size=14.6667px]

[size=14.6667px]I tried closed DJI GO 4 apps and reopened again, it couldn't connect to my Mavic Pro. I tried to look for the Mavic location but can't really judge where was it located since my concentration was on the screen taking the footage. Here is the map and the flight logs




[size=14.6667px]"H" was the took off point, I tried to look at Yellow area to locate my Mavic, because I wasn't sure where was it located. I was in panic mode, still can't see it anywhere at the Yellow area. After a minute or so, I tried looked at other area where "T" was, then I saw a Mavic hover in the sky.
[size=14.6667px]

[size=14.6667px]There were couple of Mavic and Phantom crafts around, not too sure was that mine. I tried move left and right on my RC stick, the movement seems like what I controlled, then i tried move toward me... and YES, that was my mavic. At that time DJI GO 4 apps still not working, status were still "Aircraft Disconnected". Besides, there were no RTH trigger on the Mavic too ;(
[size=14.6667px]

[size=14.6667px]As you can see, the flight record ended at "T", in theory the Mavic was stuck there. Lucky I was able to identify my Mavic Pro and slowly brought it back to me.
[size=14.6667px]

[size=14.6667px]When the Mavic was above me, I tried to power off the RC and power on again, I was able to connected to Mavic Pro on DJI GO 4 Apps again. I was thinking to power off/on the RC when I saw the Mavic from far, but worried it couldn't connect it back, since RC still have control. It was best to bring it back.
[size=14.6667px]

[size=14.6667px]It was a scary experience. It's the same bad experience the guys had while shooting The Bund at ShangHai.
[size=14.6667px]

[size=14.6667px]Refer to the picture below, I was controlling 2 meters away from the tent in red square. The LOS was clear between my RC to the aircraft, there were no tall building around.
[size=14.6667px]



[size=14.6667px]Below is the footage.[size=14.6667px]


I hope that DJI Support can assist to find out what was the problem. So it can help others to understand too.

Sorry that I forgot to mentioned the DJI GO 4 apps was running on Samsung S7 Edge (Android 7.0)

Wow... That picture explains a lot.

• That looks like an area full of people and therefore full of electronic devices, which is basically pushing and pulling information heavily in that area and its surrounding... which can lead to interference...
• Also, how many of those people has a drone causing more inteference.
  

Radio interference cannot be a root cause because there was no RC connection lost. It was a RC-to-phone connection issue that has bees solved by RC restart.
This is definitelly looks like a critical bug in RC firmware.

cluc Posted at 2017-2-8 21:01
Wow... That picture explains a lot.

That looks like an area full of people and therefore full of electronic devices, which is basically pushing and pulling information heavily in that area and its surrounding... which can lead to interference...

Also, how many of those people has a drone causing more inteference.

I did further reading. it could be interference surrounded by the people, and some other drones around too.

Sergey_B Posted at 2017-2-8 22:16
Radio interference cannot be a root cause because there was no RC connection lost. It was a RC-to-phone connection issue that has bees solved by RC restart.
This is definitelly looks like a critical bug in RC firmware.

You are right.

The RC connection to the Mavic still works (luckily), the only thing is the DJI GO 4 Apps said "Aircraft Disconnected", close and open the apps also cannot connect to the Mavic.

I was hoping it was RC Connection lost, at least the RTH will be triggered (I think it will, haven't try that  out ;D).

Wondering could it be the 2.4Ghz interference where it stream from Mavic camera to DJI GO 4 Apps.

I hereby attach the flight record data too.

coconutbun Posted at 2017-2-8 19:25
Sorry that I forgot to mentioned the DJI GO 4 apps was running on Samsung S7 Edge (Android 7.0)

Congratulations on getting control back :-) The fact that you're using S7 Edge could potentially be a factor - there have been previous reports that the app was crashing on the phone. Sometimes it was also the quality of the cable connecting the phone to the RC - worth checking since you can use any cable including the original Samsung one for connection.

Remember that if you lose the app in the phone, you still have the controller on your hands! and it's got a wonderful RTH button! RTH won't be triggered automatically unles the RC and Drone connection is lost, the app is just secondary.

Hi.

The message "Aircraft Disconnected" does not tell the TRUTH. You should read it as "DJIGO4 have lost contact with your RC" and just fly ahead with the RC, that will work as usual.

Regards Leif.

rnrnrn Posted at 2017-2-9 01:00
Congratulations on getting control back :-) The fact that you're using S7 Edge could potentially be a factor - there have been previous reports that the app was crashing on the phone. Sometimes it was also the quality of the cable connecting the phone to the RC - worth checking since you can use any cable including the original Samsung one for connection.

Thanks ;) Good to have it back.

I don't have the apps crash problem, the apps able to close and launch. As for cable, I was still using he original comes with Mavic.

My first 15 minutes flight was all great, this was 2nd flight after I swap another fully charged battery.

CuaC Posted at 2017-2-9 01:06
Remember that if you lose the app in the phone, you still have the controller on your hands! and it's got a wonderful RTH button! RTH won't be triggered automatically unles the RC and Drone connection is lost, the app is just secondary.

When I saw the Mavic, I was thinking to press on the RTH button. But I doubt to that because the DJI GO 4 apps were not working, I don't want it accidentally land on the cars parked around home point ;)

I need to read the manual too, while Mavic is RTH-ing, can I press the RTH button again to cancel the descend landing.

As mentioned above, "Aircraft Disconnected" was 2nd flight. I did 1st flight for 15 minutes. Land, changed battery and go fly the Mavic again.

Flightlog 1 - Flight launched at 7:32am
Flightlog 2 - Flight launched at 7:50am

This happened to me countless times with my iPhone 6 Plus. Problem went away when i changed phones. Anyhow, just unplug the cable to your galaxy S7 and plug it back in and the image will re-connect and the image will come back.. no need to even exit the app or restart controller. Just unplug, and plug back in. Alternatively, connect it via the USB port if it keeps happening. That also solved my issue when using the one phone.

Its nothing big to worry about. These are software issues and will come and go. The aircraft is still 100% in control whilst this is happening. If you get worried or anything, just press RTH (assuming you set it up correctly each time etc.) Happy flying.

Stu-pak Posted at 2017-2-9 06:37
This happened to me countless times with my iPhone 6 Plus. Problem went away when i changed phones. Anyhow, just unplug the cable to your galaxy S7 and plug it back in and the image will re-connect and the image will come back.. no need to even exit the app or restart controller. Just unplug, and plug back in. Alternatively, connect it via the USB port if it keeps happening. That also solved my issue when using the one phone.

Its nothing big to worry about. These are software issues and will come and go. The aircraft is still 100% in control whilst this is happening. If you get worried or anything, just press RTH (assuming you set it up correctly each time etc.)  Happy flying.

Thanks for the tips. I know what to do next time ;) Unplug the cable instead of restart the RC.

Great info.. I love fellow pilots feedback and sharing.

I had the same exact situation happened today. My DJI GO 4 was running on Samsung Galaxy S6. The App got frozen with message "Aircraft Disconnected", which is scary because there was no indications before it got disconnect. Luckily  the RC is still in control and press the RTH button to fly it back. It never happened before though. I had been flying it for the past two months. And this is the first time it ever happened. I would assume that DJI GO 4 was interfered by DJI GO that was running on this phone before even though I intentionally killed it before starting GO4.  I guess I have to restart the phone every time before I run GO4.

coconutbun Posted at 2017-2-9 19:11
Thanks for the tips. I know what to do next time ;) Unplug the cable instead of restart the RC.

Great info.. I love fellow pilots feedback and sharing.

Where can I find the DJI Flightrecord log? It seems my phone only shows up to when it got disconnected. Does the drone store flight record on its own?

cyadji Posted at 2017-2-10 06:50
Where can I find the DJI Flightrecord log? It seems my phone only shows up to when it got disconnected. Does the drone store flight record on its own?

Yes. You might get it through DJI Assistant when connect Mavic through USB to PC. Connect cable then start DJI Assistant? then powering Mavic. When App catch USB connection, PC mount new device with log files. You might simple copy it to PC.  

Landbo Posted at 2017-2-9 03:04
Hi.

The message "Aircraft Disconnected" does not tell the TRUTH. You should read it as "DJIGO4 have lost contact with your RC" and just fly ahead with the RC, that will work as usual.

+1

The message that appears is not well stated. I've seen lots of folks ask on forums "Why didn't I get a low signal or interference warning before this happened?" Which of course they won't ever get because it has nothing to do with the connection to the aircraft.
Edit to say i should have said: It Appears to have nothing to do with the connection to the aircraft. I don't have any specific knowledge of the inner workings of the system.

Alx Posted at 2017-2-10 07:45
Yes. You might get it through DJI Assistant when connect Mavic through USB to PC. Connect cable then start DJI Assistant? then powering Mavic. When App catch USB connection, PC mount new device with log files. You might simple copy it to PC.

Thanks. I got DJI Assistant 2 installed and connected to MP successfully. However, the flight log panel seems empty. I saved the blackbox data and app data on that flight time as well. Both of them looked gibberish to me. So I guess it is different from regular flight log since it is a text file.

cyadji Posted at 2017-2-10 18:17
Thanks. I got DJI Assistant 2 installed and connected to MP successfully. However, the flight log panel seems empty. I saved the blackbox data and app data on that flight time as well. Both of them looked gibberish to me. So I guess it is different from regular flight log since it is a text file.

Hey, DJI Go 4 Apps in Android, the flight logs are saved into my phone. The logs I uploaded it was retrieved via /sdcard/dji/* folder. In iOS i am not quite sure.

There is not DJI personal comment on this, so I guess it's not a "serious" issue?

Hi folks, I have the same issue here. Almost lost my Mavic too. Was flying a bit out of sight. Thank god I was able to fly back using the distance value on the RC.
Anyway, this started after upgrading the Mavic to the latest firmware. Wondering if that might be the problem here.
Anyone?

mrodig Posted at 2017-4-1 08:40
Hi folks, I have the same issue here. Almost lost my Mavic too. Was flying a bit out of sight. Thank god I was able to fly back using the distance value on the RC.
Anyway, this started after upgrading the Mavic to the latest firmware. Wondering if that might be the problem here.
Anyone?

Please upload the logs from the flight and provide a link, which may put us in a better position to speculate on what the problem might have been.