Hello,

Yesterday, I lost my Mavic Pro. After a few seconds, it becames completely uncontrollable. It flew alone in a direction, and there was nothing I could do with the RC. It did not respond to the RC at all.

I tried the RTH button, but it did not fly back to home point. At some point, I lost the connection as it flew alone.

I am extremely mad about it, and it must be caused by a serious bug.

I attached LOGS as a zip file here. Could you please have a look at the logs in order to try to understand what exactly happened ?

Thank you

Sorry for your loss, please refer to the link below to contact the Support, then provide the log to them, they will start a case and submit a data analysis for you. http://www.dji.com/support

Keep us informed....I try and fly everyday....it would crush me to loose one of my birds

Can you upload your flight log to link below it may well give you more info as to regards what happened.
Just click on link and follow instructions come back here and post link.

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

Here are the links to your flight logs:

Part 1
Part 2

It looks like you were regularly getting disconnected from the aircraft during the flight which is why the log is in two parts, but that wasn't what caused this. You flew downwind at a moderately high altitude when there was a fairly strong wind near ground level. Then, when RTH was initiated by one of the longer disconnections the Mavic just wasn't able to fight the wind enough to return. It looks like you canceled RTH and tried to fly it back manually but you weren't in Sport mode so it still didn't have enough power to fight the wind.

You continued to lose ground and eventually RTH was initiated again after another disconnection. You deliberately reduced its height from the RTH altitude (70m / 230 feet), and that caused the final disconnection because there wasn't an unobstructed path between the Mavic and its controller.

Its last recorded location was here, but it was still being pushed southeast by the wind at that point. It still had 29% battery at the time of the last disconnection so it would have continued flying until it reached the critically low battery level, at which point it would begin landing automatically. The line along which it was being pushed roughly corresponds to what's shown in the picture below, so I'd begin at its last known location (43.33561469, 6.65908007) and move southeast along that line to look for it. Based on the speed that the wind was pushing it I'd guess that it didn't go more than 150m southeast of that last known position, which would put it no farther away than here.

Given the hilly nature of the area and the presence of so many trees I'd say your best bet would be to get someone else who owns a drone to fly around that area to look for it. If that isn't an option, though, your best option is to look around there and start asking the people who live along that path if they happened to find it. Good luck.

I'm afraid droneflying is pretty close to the mark, wind was against you , when this happens telemetry is your friend. You should try search for it plenty of houses in that area someone may have heard it land or crash.
Good luck

It's always the drones fault. I didn't do anything wrong and I'm mad at DJI!

DroneFlying Posted at 2017-8-20 04:45
Here are the links to your flight logs:

Part 1

WOW, that's some serious in-depth analysis of the flight logs.
Nice work Sherlock. Seriously nice work.

DroneFlying Posted at 2017-8-20 04:45
Here are the links to your flight logs:

Part 1

hey drone flying - to my novice eye it looks like you have provided a very good and accurate analysis. well done and thank you (cause i am trying to figure these logs out and following yr lead helps me.

ghostrdr Posted at 2017-8-20 08:20
It's always the drones fault. I didn't do anything wrong and I'm mad at DJI!

It is not always the drones fault -  regular users and participants on this forum like 'droneflying' read the data and present their findings based on that data.
On the occasion that we have seen that data shows drone malfunction - then we all give dji a hard time.
But when the data does not show that it is drone error then we do not blame dji - we do not blame anyone - just provide data based analysis.

Where do you download the logs from please?

hey Ben - hope you find yr drone. drop yr contact details at properties in the area and i hope someone will get back to you. Drone could be in a tree so be sure to make a follow up visit to the area after some heavy winds. Droneflying analysis corresponds with my view - you got blown away by a headwind that was stronger than mavics RTH potential. :-(

Maveriksam Posted at 2017-8-20 09:05
WOW, that's some serious in-depth analysis of the flight logs.
Nice work Sherlock. Seriously nice work.

Seriously, this is such great analysis of a very unfortunate and expensive situation. Wouldnt it be helpful though if DJI provided more disclosure documentation and tutorials to avoid this and other similar pitfalls, along with the packaging rather than just letting the inexperienced experiment with an expensive toy?!?!?!

Thanks for the compliments, guys. I appreciate it.

Sparkless, there are two types of logs: the TXT files created on the mobile device by the Go app, and the DAT files stored on the Mavic itself. The DAT files contain far more information about the flight, but obviously they can only be examined in cases where the drone is retrieved and still at least somewhat functional. Instructions for retrieving the TXT files are here and for the DAT files are here.

Bekaru Tree Posted at 2017-8-20 10:52
It is not always the drones fault -  regular users and participants on this forum like 'droneflying' read the data and present their findings based on that data.
On the occasion that we have seen that data shows drone malfunction - then we all give dji a hard time.
But when the data does not show that it is drone error then we do not blame dji - we do not blame anyone - just provide data based analysis.

I could be wrong, but I think his post was scarcastic in nature - maybe not helpful, but still sarcastic.

Sparkless Dad Posted at 2017-8-20 11:03
Seriously, this is such great analysis of a very unfortunate and expensive situation. Wouldnt it be helpful though if DJI provided more disclosure documentation and tutorials to avoid this and other similar pitfalls, along with the packaging rather than just letting the inexperienced experiment with an expensive toy?!?!?!

hey sparkless - not having a go at you but actually regards this problem all the relevant documentation is in place. Dji states the RTH speed and also that we must fly in VLOS and also that pilots must not fly in winds exceeding 10m/s.
Had the pilot done this then he would not have lost his drone - but him, like me and many others have pushed the limits - some got lucky others got unlucky - i really feel for them as i have come close to losing my drone a few times.
Personally when new commers arrive i always warn them about the wind but ultimately the onus is on us as pilots who risk flying outside of these parameters specified by dji  to learn from experiance what the cause and effect of situations (outside those advised parameters) means to us as pilots.
They do not cover flying in winds higher than 10m/s because that is their safe limit based on their knowlage of the mavics potential and they do provide that information- when we fly in winds higher than that it takes skill, experiance and or luck to survive.

Nikon 1 Posted at 2017-8-20 11:43
I could be wrong, but I think his post was scarcastic in nature - maybe not helpful, but still sarcastic.

oops - thanks Nikon - i missed the possible sarcasm - but as u say it is not helpful except for the +1 point they got for it - not worth the hurt it causes to a guy who is already suffering the pains of losing his drone.

DroneFlying Posted at 2017-8-20 04:45
Here are the links to your flight logs:

Part 1

You did not suck this amazing in-depth analysis out of your thumbs, therefore you have used plenty of your precious time and software tools to help you.
Why must DJI drone owners always bother you to do this analysis for them?
Why are these tools not made available for every DJI drone owner?

Nikon 1 Posted at 2017-8-20 11:43
I could be wrong, but I think his post was scarcastic in nature - maybe not helpful, but still sarcastic.

Thank you. I'm not unsympathetic to the OP and any individual unit can be subject to manufacturing defects but to imply a general software defect when you've ignored warning signals like disconnects and high winds after you've lost the drone is immature. It may still prove to be a DJI error and hopefully after the expert diagnostics provided here, the drone can be recovered. I could easily find myself in the same situation and would appreciate all of the expert assistance available here. I know that I would wait until the process is complete before assigning blame to the manufacturer.

MARSAN Posted at 2017-8-20 13:20
You did not suck this amazing in-depth analysis out of your thumbs, therefore you have used plenty of your precious time and software tools to help you.
Why must DJI drone owners always bother you to do this analysis for them?
Why are these tools not made available for every DJI drone owner?

Why are these tools not made available for every DJI drone owner?

They are. I used PhantomHelp in this particular case and for DAT file analysis I use BudWalker's CsvView and DatCon utilities.

Anyway, I'm glad you brought this up because while I certainly appreciate the accolades I should point out that none of it would be possible without Mike's PhantomHelp site (in this case) or BudWalker's utilities (in various others), not to mention the information that I've acquired directly or indirectly from them.

ghostrdr Posted at 2017-8-20 13:25
Thank you. I'm not unsympathetic to the OP and any individual unit can be subject to manufacturing defects but to imply a general software defect when you've ignored warning signals like disconnects and high winds after you've lost the drone is immature. It may still prove to be a DJI error and hopefully after the expert diagnostics provided here, the drone can be recovered. I could easily find myself in the same situation and would appreciate all of the expert assistance available here. I know that I would wait until the process is complete before assigning blame to the manufacturer.

I would never fly my Mavic in high winds, Beaufort 4 is definitely my limit, because very often there will be gusts of wind in the Beaufort 5 to 6 range.
Those gusts of wind are deadly for the lightweight Mavic.

To get a good idea of what the Beaufort scale looks like on land, I found this Wikipedia article useful:
https://en.wikipedia.org/wiki/Beaufort_scale

ghostrdr Posted at 2017-8-20 13:25
Thank you. I'm not unsympathetic to the OP and any individual unit can be subject to manufacturing defects but to imply a general software defect when you've ignored warning signals like disconnects and high winds after you've lost the drone is immature. It may still prove to be a DJI error and hopefully after the expert diagnostics provided here, the drone can be recovered. I could easily find myself in the same situation and would appreciate all of the expert assistance available here. I know that I would wait until the process is complete before assigning blame to the manufacturer.

One thing I've noticed - many times sarcasm is lost on a bulletin board and even more so To citizens of other nations.

I completely agree with you that many people would like to blame DJI, either for software or hardware failures when it's just as likely to be a self-induced problem.  Thankfully, I've never experienced a fly-away or loss of control issue - and I hope my luck holds out - but if it happens, thankfully there are a number of highly experienced pilots here to help out.

My original comment on your post was not to dump on you though in re-reading it, I was a little harsh without meaning to be.

Good Flying!

DroneFlying Posted at 2017-8-20 13:26
Why are these tools not made available for every DJI drone owner?

They are. I used PhantomHelp in this particular case and for DAT file analysis I use BudWalker's CsvView and DatCon utilities.

But these software tools are not DJI tools, therefore are they still free of charge?
Is there a manual and/or a tutorial available to learn how to use these tools?

MARSAN Posted at 2017-8-20 13:41
But these software tools are not DJI tools, therefore are they still free of charge?
Is there a manual and/or a tutorial available to learn how to use these tools?

But these software tools are not DJI tools, therefore are they still free of charge?

Yes, all free.

Is there a manual and/or a tutorial available to learn how to use these tools?

Not exactly. BudWalker has provided some information on his web site and I've found him helpful when I had questions, but for the most part it's something I've learned by doing and by seeing how he uses the tools. I'd guess that Mike's probably willing to answer questions too, but I've never really had a reason to ask him anything.

DroneFlying Posted at 2017-8-20 13:50
But these software tools are not DJI tools, therefore are they still free of charge?

Yes, all free.

Well, there you go, these useful utilities are unfortunately not supported by DJI and drone pilots have to learn the use of those tools by themselves.

Would it be useful to start a thread explaining the use of these tools and those drone owners who are interested could contribute useful information to this thread?

telemetry and warnings are your annoying friend...  also have to consider before even flying, the weather, wind, if wind changing directions or not, interference may encounter.. and you have to reconsider all these factors every hundred feet..  i havent read the logss just the chat here... im not trying to grill anyone here..

i maybe newer, just getting started, but some common sense logic everyone should have.  think about ground level conditions, and then consider conditions higher up will be more severe...even if ground level is 1 mph breeze on your back at most and mostly calm, i flown out over a field with my spark i used to own, and found the field as turned into a valley increased wind speed slight may only been flying 50 feet AGL from where i took off.  but once over the field in the valley i was 350 feet up off that ground and learned how quickly 1 mph breeze can turn into 5 mph constant wind up there, either sinking air or rising air.. or something..i need to learn about.   5mph does not sound bad i flown in harder winds, but once i got out 1 mile no wind warnings or anything no adjustments being made on aircraft i guess.., i had to land it on the farm driveway and retrieve it..didn't have the battery to get back in the little spark..and yea, i started with 80% battery part of my issue so 1 mile out pushed my battery down into mid 40% range coming back fighting wind chewed my battery up only made it half way back up before critical battery hit..

the other issue is checking signal, once you hit a wall where signal is becoming garbage, turn around or start RTH and then get it some distance back to u then cancel it..  even with occusync, still talking about 2.4Ghz signal and its fairly easy to shield 2.4Ghz..  so with weakened signal, fligh higher....  get distance up in the air to increase the LoS for the RF and to also distance self from possible interferences maybe effectively jamming the occusync from below.. if that fails, enable sport mode, turn around and start RTH and only push the right stick up all the way (default for moving forward) that will keep ur RTH going but it allow you to push forward faster..  if all this fails, then only hope is to get come control of it and land it somewhere and then chase after it..

DroneFlying Posted at 2017-8-20 11:31
Thanks for the compliments, guys. I appreciate it.

Sparkless, there are two types of logs: the TXT files created on the mobile device by the Go app, and the DAT files stored on the Mavic itself. The DAT files contain far more information about the flight, but obviously they can only be examined in cases where the drone is retrieved and still at least somewhat functional. Instructions for retrieving the TXT files are here and for the DAT files are here.

Thanks for providing the links to find the txt and dat files ->  However the instructions say :
' For Android devices:
Connect your device to a computer via a USB cable and go to "DJI/dji.pilot/FlightRecord" (for DJI GO 3) or "DJI/dji.go.v4/FlightRecord" (for DJI GO 4). '

When I check my SD card - I don't have a Dji/dji.pilot/FlightRecord directory - I have /DJI/dji.go.v4/DJI_RECORD directory and that is all - in there are mp4 and info files .

Nothing else under DJI .
Please advise - thank you

Hello,

Thank you so much for these info, it really helps understand better.

Unfortunately, after long search, I didn't succeed in finding the lost mavic... that really sucks!

DJI support replied explaining the following:

"1. Aircraft flew well with GPS mode, and responded to Pilot's command well. The aircraft was under the interference of wind during the flight.
2. At flight time 01'37'', H=51m, D=280m. Aircraft tilted 14.1 degrees forward and tilted 8.3 degrees to the right, and had a moving speed of 5.8 m/s to the left rear without command inputting , which indicated that the aircraft was influenced by strong winds.
3. At flight time 02'42'', H=49m, D=573m, the aircraft entered Go-home mode when the pilot triggered one-tap return-to-home with remote, but aircraft can't return home and was blown farther and farther away.
4. At flight time 03'53'', H=68m, D=664m, the flight record ended.

In the another flight record, the aircraft was blown farther and farther away. At flight time 07'23'', H=34m, D=1820m, the flight record ended.

According to the analysis, the incident was not caused by any product malfunction factors. As such, we could not provide warranty service."
What I do not understand is that when I uploaded the logs on airdata, it mentionned that the wind was around 13mph, which is far beyond the level 5 wind DJI mention (19 to 24 mph). How could the Mavic be blown farther and farther away with this 13mph wind ?

Thank you.