DJI Drone Help Forum

Lost connection, lost Mavic Mini, help please with this flyaway!

Hello,

I was happily flying my Mavic Mini until it lost connection. It said it would RTH within 11seconds if it hadn’t re-connected - but this never happened, see logs here: https://www.phantomhelp.com/LogViewer/1K72YDGOWW1SX30EISO6/

I’m guessing it’s lost at sea. Can anyone assist in explaining what happened? Thanks in advance!

Hi Tom,

sorry for your loss. Log does not explain what happend. Last records your MM approx heading towards home, in hover and needed 7 to 8 degrees nose down to keep in position.
RTH height was set to 92 meters (why that high), so my guess it started a RTH and in that mode it was not able to get enough ground speed to come closer to home due to head-wind. That`s the only logical reason for a MM not to return to home. (or in RTH a bird strike / crash or …) Some MM suffer for less power when the batt level is below a 30% value. 43% in your flight last record.

cheers
JJB

@JJB I agree with that. The only exception being that Airdata reports practically no wind at all, even at altitude. The max wind detailed was 12mph. Much less at the point of disconnect and there were no wind warnings. Also, per the data, RTH was never initiated that I can see. So an “autoland” after disconnect is possible I would think.

Hi both, thanks very much for your response, appreciate it a lot. I’ve attached the other version of the flight logs if that provides any more insight?

What’s the likelihood of DGI offering a replacement? Aware that the Care Refresh package requires a physical aircraft to be sent back to them - something that I can’t do in this case… DJIFlightRecord_2020-07-09_[16-02-45].txt (1.9 MB)

That is the same file you uploaded previously to the log viewer. No help there…but you can try uploading the device .dat…for a bit more data…may not help in this case but worth a shot…

Mobile device DAT files (DJI GO 4 & DJI Fly)

These are retrieved by the same method as the TXT logs. Under both iOS and Android they are in a subfolder, MCDatFlightRecords , in the folder that contains the TXT logs.​

Oops, thanks - you can probably tell I’m relatively new to all this! I tried to upload the .dat file but it was too big (over 4MB) - but here’s a dropbox link, not sure if you can access that? https://www.dropbox.com/s/3vm7va7o4nnl7op/2020-07-09_16-01-27_FLY005.DAT?dl=0

Hi Tom,

I am not a specialist in reading DAT files, but the file starts with a compass needs calibration.
Compass calibration is not performed before this flight.

During the flight many compass faults, On and OFF, see charts (first and last set of data shown, middel part same errors).

So possible after the disconnect a RTH did start (normal sw action after 11 secs) and MM could not find home beacuse of compass faults. Using all batt power to the end, finally a critical batt landing somewhere…

cheers
JJB

Hi JJB, sorry for the late response. Thanks for looking into this. That’s interesting, should I have received any errors during the flight to let me know about these faults? If I had seen anything telling me there was a fault I would have brought it back immediately! Still awaiting a final response from DJI. Should the drone have let me take off without the compass being calibrated, or at the time of takeoff did it think the compass was OK but it was actually just going into fault-mode on and off?

not sure, i missed once a MM compass calibration (on the screen recorder i saw i missed the message), but i could go fly and in my flight nothing happend.

Seeing many dat files ; in all files the On Off compass fault is there but just few times in a 25 minute flight. Not like your flight, many of them.

DJI should explain this.

cheers
JJB

Good to know, thanks again. Will let you know DJIs response!

Cheers

Tom

Well well, DJI have confirmed that it is a warranty case after doing their data analysis, and should be sending a new drone to me soon - happy days! Thanks again for all your input everyone. Happy flying.

Good news for you (and for DJI as reliable company)

Happy many landings,

cheers
JJB

Hi all, me again!

So a similar thing ALMOST happened today - flying around the same spot (yes, I know, silly me), and it lost connection out of the blue again. Luckily this time it did RTH and the drone is fine. It has though, made me wonder if there’s something wrong with my RC? I’ve got the flight logs here, which I’ve also sent to DJI to see if they can shed any light… Makes me so nervous to fly it! Anyone got any ideas whether this is a common issue or maybe something wrong with my new drone/RC? DJIFlightRecord_2020-08-11_[17-09-28].txt (943.9 KB) 2020-08-11_17-08-43_FLY015.DAT (966.8 KB)

In the DAT and TXT nothing to be found, so cannot help you (mayby others can)

Hey mate, if your having similar problem in same area, then maybe consider there is some interference of some sort.
Any powerlines, comms towers or electrical sub station around that could be interfering with the signal ??