My Zoom flew away

[Wyldwings]

After more than 250 miles flown over 8 months, yesterday my Mavic Zoom simply flew away. I had a fully charged battery, more than 50% on the controller, and perfect flying conditions. I took off, flew about 900 feet away over fairly level terrain and suddenly got a weak signal notice . . . and that was that. I could hear the drone continue flying for a moment and then it was silent. The controller screen simply said "Connecting . . ." After a few moments I hit the RTH button but the controller continued to read "Connecting . . . "I used the gps map from my iPad Mini and went right to the location where the drone was supposed to be, but quickly realized that was simply the location of the last communication between the drone and the controller. I searched everywhere but there is a lot of underbrush, etc. so my efforts were unsuccessful. This is really depressing. I've never had any problems with my drone previously and have thoroughly enjoyed flying it in all types of terrain. I can't think of anything I could or should have done differently but if anyone has any ideas, I'd like to know before I purchase another one.

 

[sar104]

These aircraft don't simply fly away, and so there is no way to answer your question without at least seeing the flight log file.

 

[Wyldwings]

These aircraft don't simply fly away, and so there is no way to answer your question without at least seeing the flight log file.

When I get home tonight I'm going to try and get that done. Thanks.

 

[MAvic_South_Oz]

When I get home tonight I'm going to try and get that done. Thanks.

Do that, these analysis are pretty helpful, and more than a few pilots have used the estimated location given to find their lost drone !!
Follow instructions here . . .

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

. . . or on Airdata (check sar104 post sig line for the link).
Good luck with it.

 

[Saigondroner]

When I get home tonight I'm going to try and get that done. Thanks.

By all means do; Sar104 is a a ‘mahatma’ when deciphering logs, and pinpointing the real problem. :-D

 

[miorazeem]

Firstly, i felt sad with your lost drone. Cant say much but for me..to avoid any mishaps like this, i'll double confirm my home point is updated everytime i start my flight..

 

[Wyldwings]

Is this what I'm looking for??? Sorry, I'm such a rookie on this part.

 

[sar104]

Is this what I'm looking for??? Sorry, I'm such a rookie on this part.

No - those are the wrong files from the wrong directory. Did you read the instructions in the post linked above (and below):

Mobile device DJI TXT logs​

​

The log naming convention, based on the date and time of the start of the flight, is: DJIFlightRecord_YYYY_MM_DD_[hr-min-sec].txt.​

​

Detailed instructions are available on @msinger's excellent PhantomHelp website and also on AirData, but the basic details are as follows:​

​

With iOS devices running DJI GO 4 you need to access the app files via computer, either using iTunes or with a file system browser such as iExplorer. The TXT logs are in Apps » DJI GO 4 » FlightRecords. The same method can be used to access DJI Fly files in DJI Fly » FlightRecords, but with DJI Fly they are also accessible using the iOS Files app by selecting Browse » On My iPhone » DJI Fly » FlightRecords.​

​

With Android devices the file system should mount when plugged into a Windows machine, or via various software options on a Mac. With DJI GO 4 the TXT logs are in DJI » dji.go.v4 » FlightRecord. With DJI Fly they are in DJI » dji.go.v5 » FlightRecord.​

​

If you want help analyzing the data then you can either retrieve the logs and post them here directly, or upload them to PhantomHelp or AirData and post the link back here.​

​

AirData also has automatic log upload (sync) options directly from most of the common control apps.​

 

[Wyldwings]

How about now?

 

[Wyldwings]

Hey, I'm getting the hang of this. So I uploaded the file on PhantomHelp and it shows the last entry as the last message I got -- Weak signal. But I was standing only 900 feet away on fairly level terrain in plain site of the drone.

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[MAvic_South_Oz]

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

That's not the right TXT file (?), it shows you got home ok, all be it with multiple issues / warnings.

Ah, just saw your last post.

 

[sar104]

That's the file. The evidence is circumstantial but very suggestive. Looking at elevator input, pitch and forwards velocity shows the following at the end of the flight - the aircraft is flying forwards at 19.5 m/s under full forward elevator in sport mode, pitched forwards at 30°. Right at the end, you released the elevator suddenly. The data are not recorded due to telemetry latency, but that will have pitched the aircraft back rapidly to full available backwards pitch (~35°). The maneuver almost certainly dislodged the battery and killed aircraft power, losing motors and telemetry.



There is uncertainty on how much braking that maneuver managed before power failure, but likely not much. Based on the last recorded velocity we can estimate the descent trajectory using an aerodynamic drag model for the Mavic 2, giving the following:



Plotting the descent track on Google Earth:



The far yellow pin represents the descent if the aircraft didn't significantly brake before losing power - i.e. the furthest it should have travelled. I'd start there and look back towards the last recorded point.

 

[MAvic_South_Oz]

Something to go on there . . . good luck with the search, from 158' there may be scattered wreckage.
Unless you have Care Refresh and do find some of the aircraft ?

 

[BigAl07]

Great work @sar104 .

 

[GregE]

That's so impressive!! I have much to learn

 

[Mavic Mike 2]

Have to say very impressed with this thread sorry about your loss ... but good work on the findings and evidence of what went wrong , deffo glad joined mp.com learnt loads in just one month ?

 

[Sammyh]

Top work there @sar104 very impressive and GL with finding your drone @Wyldwings
?

 

[JORGE SM]

It seems that the problem that the batteries are released, we are alerting those who read these misfortunes.

I have already made the decision to check that the battery fits perfectly, to put a velcro strip to tie the battery.

Have luck with the recovery of the ZOOM. I lost a mavic pro in a river and it is fatal. Now I am with an M 2 ZOOM and I take care of it so much that I don't even take it out¡

 

[chriscuk]

Is it common for batteries to be ejected on sometihng like the zoom? I'd have thought the locking mech that requires button presses to release would have made an accidental ejection rather tricky. With the old phantoms I've had a battery slide out but would have thought it was harder to eject them considering they check t osee if the battery is clicked in properly. I got a warning the other flight reminding me the battery wasn't clicked in properly. The drone would have taken off but it did tell me it wasn't secure and sure enough I pressed it and it clicked in.

 

[scoble08]

That's the file. The evidence is circumstantial but very suggestive. Looking at elevator input, pitch and forwards velocity shows the following at the end of the flight - the aircraft is flying forwards at 19.5 m/s under full forward elevator in sport mode, pitched forwards at 30°. Right at the end, you released the elevator suddenly. The data are not recorded due to telemetry latency, but that will have pitched the aircraft back rapidly to full available backwards pitch (~35°). The maneuver almost certainly dislodged the battery and killed aircraft power, losing motors and telemetry.

View attachment 92392

There is uncertainty on how much braking that maneuver managed before power failure, but likely not much. Based on the last recorded velocity we can estimate the descent trajectory using an aerodynamic drag model for the Mavic 2, giving the following:

View attachment 92393

Plotting the descent track on Google Earth:

View attachment 92394

The far yellow pin represents the descent if the aircraft didn't significantly brake before losing power - i.e. the furthest it should have travelled. I'd start there and look back towards the last recorded point.

Fantastic @sar104