Mavic Pro Disconnect During Flight: A Tale of Woe...TF!

TMB Aerial · Dec 2, 2016

Week #2 and my confidence in the Mavic Pro dwindles. Short story long I took the Mavic to a local park for some stick time, flew three sorties and on the third flight I lost signal 5 minutes in at a distance of 1,989 ft. The Mavic was out of my line of sight so I waited about 3-4 minutes and still got no signal and was not seeing/hearing the Mavic return. So I took off running towards where I lost signal at (baseball field). As I got about halfway there the controller connected and I got a "returning to home" message on the screen. I stood there listening and about 30 seconds or so I heard the Mavic overhead flying towards the home location. So I ran back and it was at the home location, hovering about 3 ft off the ground. Landed and all was good, but WHY!?

Some details: Of the three flights I flew the first using the DJI GO 4 app (I'm still having intermittent issues connecting a Samsung Galaxy S7 Edge). once I had a stable connection I took off from a big empty field of grass and made one pass around the lake. Took video, have video...no disconnects, smooth video feed...no problems.

Flight two I switched to the Litchi app (updated version 3.9.2) so I could fly with VR Goggles (my S7 Egde in a pair of NooNs). Again I flew around the lake. Took video, have video..no disconnects, smooth video feed...no problems. battery was getting low so I landed and swapped to a fully charged battery.

Flight three I took off from the same empty field, same setup as flight two (Litchi app, VR goggles). I flew towards the lake then decided to flt towards the baseball fields. I was a about halfway over the field when my video image froze, I waited a few seconds. At this point I wasn't getting any disconnect message from the controller or the Litchi app so I pushed the sticks alittle and waited a few more seconds, then the Litchi app lost signal, the controller said "disconected" and/or whatever else it says when it gets no flight data from the Mavic, I can't remember cause at this point I'm in WTF mode. I stupidly hit the RTH button a few times before I realize "ummm that ain't gonna work". I reboot the Litchi app (why? I dunno) and of course that did nothing. So it's been a few minutes and I don't hear or see the Mavic returning. It should have by now, right? The manual says it's suppose to return to home after 3 seconds of being disconnected from the controller. Well, it didn't so I pulled my phone off the controller, still nothing...grabbed my stuff and took off running towards the baseball field (man, I am out of shape). As I said earlier about halfway there the controller reconnected to the Mavic and I got a heading home message....(t returned, I landed it, packed everything up and headed home.

I uploaded the video first and there were 3 clips...1st flight, 2nd flight and the 3rd flight BUT a corrupt video file (3rd clip would not load/play). I tried to repair the clip but no joy. I then went for the flight logs. Tried the healthydrones app from my phone but that didn't work, connected the mavic quad to my iMac and launched DJI Assistant, put the Mavic in flight log mode and assistant would not load log files...just got a spinning whatever the heck that thing is. Tried several times then finally went to my pc and got the log files to export. I uploaded them manually to HealthyDrones and flight #1 looked great, no issues. Flight #2 shows some signal losses even though I expereinced none during flight. Flight #3 shows heavy signal loss and a flight path that just ends over the baseball field with no return data what-so-ever. The only thing that the healthy drones data does for me is confirm that I lost signal, I still have no idea why it happened. The Litchi app and the basball field were the only different variables from the first two flights. It's curious that flight #2 shows intermittent signal loss....Litchi app?? I'll attached links to all three flights below. I also plan to send all date to DJI. I plan to go back today and try to fly the same path/same set up if I can. Right now the only real confidence I have in the Mavic is the Care Refresh coverage.....I fear I will need it but I hope I will not. I'm interested in all feedback as I'm sure there are questions I'm not asking. thanks! -Dave

Flight #1 VreaBE

Flight #2 OLAEfW

Flight #3 MUNrcA

GerdS · Dec 2, 2016

I don't know your location and the specific situation there, but usually the connection gets lost when the line of sight gets lost. That's the case for all GHz based rf technology, it behaves similar to a light beam. If you will allow a building or a set of trees (forrest?) between yourself and the copter, the connection will break. The only thing you can do to prevent this is ascending. That you should have done after the video connection got lost. The uplink is usually a bit more robust than the downlink, due to its low data rate. So you should always take the loss of the downlink as a warning not to proceed and first think about your line of sight situation.

stealle · Dec 2, 2016

GerdS said:
The only thing you can do to prevent this is ascending. That you should have done after the video connection got lost.

He couldn't ascend if you he has a disconnect. As long as he has proper RTH settings, the Mavic should ascend all on it's own.

greginfinity · Dec 2, 2016

How long did you wait between flights? Any chance this is a heat issue since it was three flights in a row? Heat can certainly screw up SD cards/writes.

TMB Aerial · Dec 2, 2016

GerdS said:
I don't know your location and the specific situation there, but usually the connection gets lost when the line of sight gets lost. That's the case for all GHz based rf technology, it behaves similar to a light beam. If you will allow a building or a set of trees (forrest?) between yourself and the copter, the connection will break. The only thing you can do to prevent this is ascending. That you should have done after the video connection got lost. The uplink is usually a bit more robust than the downlink, due to its low data rate. So you should always take the loss of the downlink as a warning not to proceed and first think about your line of sight situation.

Thanks GerdS, I did NOT think of that...duh. Being an ex-commo guy I should have paid attention to that (I guess it's too easy to get so casual about flying these). I can't say for sure that was the cause but it certainly makes sense. I'm still hoping to get away today and try to recreate the failure (yea on purpose). I am stumped as to why it didn't return home sooner, I am almost certain I had it set to RTH and not "hover" But if it was set to hover it did eventually RTH (when I ran closer...) I couldn't find in the manual what the parameters are for if/when/how the Mavic responds to a signal loss within this context.

greginfinity I did not wait at all when switching batteries so that was probably it seeing as the SD card is right there next to the aluminum bottom. Thanks.

Good stuff here.

greginfinity · Dec 2, 2016

What was the weather like? I don't know if you need to wait for any cool down period with this drone (I know you should wait for battery to cool down before recharge/after charge), but I think I saw some people stating that there were issues with heat and the gimbal cover at least. So I wonder if there are more issues with the compactness of this drone? The heat could definitely cause TX/RX issues as well. I haven't seen what the PCB layout is on these but with it being compact, I would guess that heat could be an issue.

TMB Aerial · Dec 2, 2016

greginfinity said:
What was the weather like? I don't know if you need to wait for any cool down period with this drone (I know you should wait for battery to cool down before recharge/after charge), but I think I saw some people stating that there were issues with heat and the gimbal cover at least. So I wonder if there are more issues with the compactness of this drone? The heat could definitely cause TX/RX issues as well. I haven't seen what the PCB layout is on these but with it being compact, I would guess that heat could be an issue.

I'm in Raleigh, NC. it was a sunny cool day 60 degrees. max "recorded" battery temp on that last flight was 89.6 degrees

Bernard · Dec 10, 2016

I had exactly the same problem yesterday, using DJI GO 4... I lost the signal on the app and the Mavic did'nt return home... some minutes later, I could use the RTH button on the RC and the Mavic came back... No explanation...

CactusJackSlade · Dec 10, 2016

Bernard said:
I had exactly the same problem yesterday, using DJI GO 4... I lost the signal on the app and the Mavic did'nt return home... some minutes later, I could use the RTH button on the RC and the Mavic came back... No explanation...

How far away when it disconnected?... it will not go into RTH if less than 30 meters/90 feet way. (I think that is the minimum distance for RTH, have to check the manual)

CactusJackSlade · Dec 10, 2016

TMB Aerial said:
Thanks GerdS, I did NOT think of that...duh. Being an ex-commo guy I should have paid attention to that (I guess it's too easy to get so casual about flying these). I can't say for sure that was the cause but it certainly makes sense. I'm still hoping to get away today and try to recreate the failure (yea on purpose). I am stumped as to why it didn't return home sooner, I am almost certain I had it set to RTH and not "hover" But if it was set to hover it did eventually RTH (when I ran closer...) I couldn't find in the manual what the parameters are for if/when/how the Mavic responds to a signal loss within this context.

greginfinity I did not wait at all when switching batteries so that was probably it seeing as the SD card is right there next to the aluminum bottom. Thanks.

Good stuff here.

Yes, you need to maintain a clear straight line between you and the 'copter... 5.8 is worse than 2.4 as far as penetration through trees and whatnot goes. I am curious as to why it did not RTH after the three seconds. I am wondering if perhaps you lost the downlink video, but the controller was actually still connected and thus did not initiate a full RTH.

If I ever lose connection or see video break up I always hit the gas for some elevation, hoping I can climb above whatever obstruction there may/might have been...

Bernard · Dec 10, 2016

I had the same problem yesterday using DJIGO 4 app on Android : signal lost and no RTH. Some minutes later I recovered the signal on the RC, tap the RTH button on the RC and the Mavic came back... But I didn't recover the connection on the app.
Furthermore, the RTH was'nt registered on the Mavic.
HealthyDrones.com - Innovative flight data analysis that matters

Bernard · Dec 10, 2016

My Mavic was around 420 m away when I lost the signal...

CactusJackSlade · Dec 10, 2016

Almost seems like the Mavic is failing to RTH if the app crashes and sometimes when signal is lost??...

dewster · Dec 10, 2016

Crazy how these app enabled drones don't maintain reliable operation. It would be nice to have a rock solid system that doesn't rely on a phone or device's OS. DJI should design a complete system controller and iron out the bugs.

Sent from my iPhone using MavicPilots

Carlos de Castro · Dec 10, 2016

I had the same thing happen. Mavic returned, but the app never reconnected. I was in panic mode, because it was over water, but then saw the telemetry data getting closer. The regular Dji go app on android has a lot of bugs. This has happened to me twice already. I tried Dji go 4 app today, and had no problems.

Sent from my iPad using MavicPilots

CactusJackSlade · Dec 11, 2016

dewster said:
Crazy how these app enabled drones don't maintain reliable operation. It would be nice to have a rock solid system that doesn't rely on a phone or device's OS. DJI should design a complete system controller and iron out the bugs.

Sent from my iPhone using MavicPilots

With RTH, it was my understanding that the whole system IS based on if there is a loss of connection the 'copter already has the return to home instructions.... it should not need to be told to RTH, it should do so automatically if the signal fails... some coding needs to be worked out...

Florida Drone Supply · Dec 12, 2016

TMB Aerial said:
Week #2 and my confidence in the Mavic Pro dwindles. Short story long I took the Mavic to a local park for some stick time, flew three sorties and on the third flight I lost signal 5 minutes in at a distance of 1,989 ft. The Mavic was out of my line of sight so I waited about 3-4 minutes and still got no signal and was not seeing/hearing the Mavic return. So I took off running towards where I lost signal at (baseball field). As I got about halfway there the controller connected and I got a "returning to home" message on the screen. I stood there listening and about 30 seconds or so I heard the Mavic overhead flying towards the home location. So I ran back and it was at the home location, hovering about 3 ft off the ground. Landed and all was good, but WHY!?

Some details: Of the three flights I flew the first using the DJI GO 4 app (I'm still having intermittent issues connecting a Samsung Galaxy S7 Edge). once I had a stable connection I took off from a big empty field of grass and made one pass around the lake. Took video, have video...no disconnects, smooth video feed...no problems.

Flight two I switched to the Litchi app (updated version 3.9.2) so I could fly with VR Goggles (my S7 Egde in a pair of NooNs). Again I flew around the lake. Took video, have video..no disconnects, smooth video feed...no problems. battery was getting low so I landed and swapped to a fully charged battery.

Flight three I took off from the same empty field, same setup as flight two (Litchi app, VR goggles). I flew towards the lake then decided to flt towards the baseball fields. I was a about halfway over the field when my video image froze, I waited a few seconds. At this point I wasn't getting any disconnect message from the controller or the Litchi app so I pushed the sticks alittle and waited a few more seconds, then the Litchi app lost signal, the controller said "disconected" and/or whatever else it says when it gets no flight data from the Mavic, I can't remember cause at this point I'm in WTF mode. I stupidly hit the RTH button a few times before I realize "ummm that ain't gonna work". I reboot the Litchi app (why? I dunno) and of course that did nothing. So it's been a few minutes and I don't hear or see the Mavic returning. It should have by now, right? The manual says it's suppose to return to home after 3 seconds of being disconnected from the controller. Well, it didn't so I pulled my phone off the controller, still nothing...grabbed my stuff and took off running towards the baseball field (man, I am out of shape). As I said earlier about halfway there the controller reconnected to the Mavic and I got a heading home message....(t returned, I landed it, packed everything up and headed home.

I uploaded the video first and there were 3 clips...1st flight, 2nd flight and the 3rd flight BUT a corrupt video file (3rd clip would not load/play). I tried to repair the clip but no joy. I then went for the flight logs. Tried the healthydrones app from my phone but that didn't work, connected the mavic quad to my iMac and launched DJI Assistant, put the Mavic in flight log mode and assistant would not load log files...just got a spinning whatever the heck that thing is. Tried several times then finally went to my pc and got the log files to export. I uploaded them manually to HealthyDrones and flight #1 looked great, no issues. Flight #2 shows some signal losses even though I expereinced none during flight. Flight #3 shows heavy signal loss and a flight path that just ends over the baseball field with no return data what-so-ever. The only thing that the healthy drones data does for me is confirm that I lost signal, I still have no idea why it happened. The Litchi app and the basball field were the only different variables from the first two flights. It's curious that flight #2 shows intermittent signal loss....Litchi app?? I'll attached links to all three flights below. I also plan to send all date to DJI. I plan to go back today and try to fly the same path/same set up if I can. Right now the only real confidence I have in the Mavic is the Care Refresh coverage.....I fear I will need it but I hope I will not. I'm interested in all feedback as I'm sure there are questions I'm not asking. thanks! -Dave

Flight #1 VreaBE

Flight #2 OLAEfW

Flight #3 MUNrcA

Sorry to hear about your scare! One quick question I am curious to know is when you switched between the apps you were using did you fully close the one you were not using or was it running in the background? As people fly on different apps I think this is a good thing to note and track.

F6Rider · Dec 12, 2016

I will never switch app's in mid-flight, just opening the door to conflicts, if I need to switch between GO4 & Litchi then I do it at battery change after making sure the one app is fully closed. If asked I am sure both company's would not recommend such a practice.