Spark just fell off the sky

[Adrian]

Hello Guys, I got a spark not to long ago, flow it about 10 times or so. Here is what happened today which has me severely concerned:

I was flying in my backyard in sport mode, then during a turn the drone just fell off, but the power was never interrupted, one or motors stopped midair. Now I been flying for years and have several drones: Inspire, Solo, Flamewhell etc.. so I can assure you this was not operator error.

Now I am super concerned and worried about flying it again, when this happened there was a strange warning in the screen, I couldn't take a screenshot, but it is something about IMUAcceleration or something like that.
I retrieved the drone no problem as it was in my backyard and I was only about couple feet above the ground when this happened, but this could have been much worse.

Anyone else experienced this?
I connected the drone to DJI Assistant and downloaded the blackbox files, and I see a few files:
fatal.log
Kernel.log
kernel1.log and a few others, I tried opening the fatal.log, but I think it is in chinese or something like.


Any suggestions how to read the fatal.log file? I also replayed the flightdata and I did not trigger the shutdown command for the motors in case you are wondering

Thanks,

 

[Dronason]

...
Any suggestions how to read the fatal.log file? I also replayed the flightdata and I did not trigger the shutdown command for the motors in case you are wondering
Thanks,

No idea about these log, they look like binary or encrypted.
You can upload the flight log from your app here DJI Flight Log Viewer and post the link to it. It gives an overview of the flight.
The best is usually to retrieve the .DAT flight record of the Spark as explained HERE. Then you can u'pload them to something like dropbox and post a link here.
Then it can be checked more in details.

 

[LotusFan]

I have a theory about this dropping out of the sky thing:

The drone motors will turn off if you grab the drone and invert, or even turn it only 90 degrees on its side. If you are going fast, and let off the stick, the drone does its level best to stop immediately, which is not at all smooth. What if that motion, combined with the right amount of wind, gets the drone to 90 degrees off horizon? It would shut down the motors, that's what.

So I plan to just keep it smooth on the controls.

 

[Adrian]

I have a theory about this dropping out of the sky thing:

The drone motors will turn off if you grab the drone and invert, or even turn it only 90 degrees on its side. If you are going fast, and let off the stick, the drone does its level best to stop immediately, which is not at all smooth. What if that motion, combined with the right amount of wind, gets the drone to 90 degrees off horizon? It would shut down the motors, that's what.

So I plan to just keep it smooth on the controls.

That would explain things, because it was definitively doing a sharp turn.
I flew today and tried to replicate the issue, but was not able to. I am sure that Fatal.log will say the cause of the crash.

Thanks

 

[Dronason]

If you retrieved DAT file as in my post #2, you will see (or somebody will do it for you) the position of spark and motors status over the time. Crash.log sounds like a firmware crash log.

 

[Dronason]

There is limited space in the Spark to record DAT file, so older is deleted to make space for a new one.
Here is an example of what can be extracted from DAT file using CsvView tool.

Then less guessing, you can build theory on facts.

 

[Adrian]

I was able to get the log files please find it here: Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-13_13-24-39.DAT

But I have been unable to analyze it as it doesn't open with the tools mentioned here.

 

[Adrian]

Here is file from the ipad: I tried to make sense out of things with no luck.

Thanks for any help

 

[Dronason]

I was able to get the log files please find it here: Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-13_13-24-39.DAT

But I have been unable to analyze it as it doesn't open with the tools mentioned here.

Yes, it seems too small in size for real flight and there is nothing usable if it is opened with CsvView.
Idiot question, but are you sure it is the right one, you need really to select if by date/time. Each time the Spark is turned on, one file is created.

 

[Dronason]

Here is file from the ipad: I tried to make sense out of things with no luck.

Thanks for any help

Unfortunately, from the app point of view, all was good until it stopped. Battery was still at 49%, there was a GPS warning before, but nothing dramatic and it had recovered.
On the Spark point of view in the DAT would have helped to understand what happened.

 

[BudWalker]

I was able to get the log files please find it here: Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-13_13-24-39.DAT

But I have been unable to analyze it as it doesn't open with the tools mentioned here.

This isn't the correct .DAT file. There isn't a motorStart and the battery was on only 8 seconds

CsvView could do a better job at giving the user a hint. I'll be making some changes in this regard.

 

[Dronason]

This isn't the correct .DAT file. There isn't a motorStart and the battery was on only 8 seconds

CsvView could do a better job at giving the user a hint. I'll be making some changes in this regard.

Thanks in advance.

 

[Adrian]

Thank you for the responses, here is the other file for that day, this one is 56mb so I think this is the one.

Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-15_09-59-19.DAT

Thanks Again,

 

[Dronason]

Thank you for the responses, here is the other file for that day, this one is 56mb so I think this is the one.

Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-15_09-59-19.DAT

Thanks Again,

Thanks for sharing, but unfortunately, none of the 6 entries in it are related to a flight.


The reserved memory for DAT files in the Spark is limited to 6-8 flights. Any turn-on of the Spark create a DAT file even if the motors are not turned on.
It is why it is important to get such DAT file ASAP in case of issue during a flight.

 

[BudWalker]

Thanks for sharing, but unfortunately, none of the 6 entries in it are related to a flight.
View attachment 936

The reserved memory for DAT files in the Spark is limited to 6-8 flights. Any turn-on of the Spark create a DAT file even if the motors are not turned on.
It is why it is important to get such DAT file ASAP in case of issue during a flight.

Are you sure it's 6-8 flights? With all the other DJI drones the limit is 2.5 GB. That's a lot of flights. Maybe @Adrian could just extract all the flights. Anyway, I'm going to leave this in your capable hands as I'm leaving for the eclipse in Oregon. I and about 1,000,00 other people. Could be an experience somewhere between Burning Man and Woodstock.

 

[BudWalker]

I forgot to mention there is a beta version available at
CsvView Downloads
Should fix that problem seen by @Adrian 's first .DAT. If it goes OK, I'll turn it into an actual release if I make it back in one piece.

 

[Dronason]

I forgot to mention there is a beta version available at
CsvView Downloads
Should fix that problem seen by @Adrian 's first .DAT. If it goes OK, I'll turn it into an actual release if I make it back in one piece.

It gives me these warnings with the first flight data, seems ok to me:

 

[BudWalker]

It gives me these warnings with the first flight data, seems ok to me:
View attachment 937

That's "normal" because the flight is so short there isn't any data for those signals. The problem that (hopefully) got fixed was the "Can't populate .csv".

 

[Dronason]

Are you sure it's 6-8 flights? With all the other DJI drones the limit is 2.5 GB. That's a lot of flights. Maybe @Adrian could just extract all the flights. Anyway, I'm going to leave this in your capable hands as I'm leaving for the eclipse in Oregon. I and about 1,000,00 other people. Could be an experience somewhere between Burning Man and Woodstock.

That will be great trip. Come back to ground safely

In my Spark I have never seen a lot, but I was too pessimistic. Just rechecked and currently there is 14, so more than 8 oops in my Spark for a total of 1182MB. The oldest one is 2 days old but there are a lot of just turn on/off with short length. So I think it is quickly gone.

@Adrian, did you exported all flights or there was some more on the next page ? The total size you had make me thinking there should be some more.

 

[Adrian]

Hello, thanks for the help everyone I exported all the flights for Aug 11. THere is another small file in my dropbox here is the link: Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-08-15_10-01-00.DAT

Hopefully this helps,

_Adrian