Hey everyone,

I have looked everywhere for two days. Something strange happened....See video and information bellow.

In the video it looks like it crashed on top of this building..but it's not there I checked - https://goo.gl/maps/fanEioKUiLsSFKgk6

Dat file: https://www.dropbox.com/s/19gtna4pgo1pz00/FLY085-097-20210927144720.DAT?dl=0
While the sensors tell me it landed here:
https://www.google.com/maps/place/43%C2%B020'28.3%22N+17%C2%B048'55.1%22E/@43.341079,17.8146833,262m/data=!3m1!1e3!4m13!1m7!3m6!1s0x0:0x0!2zNDPCsDIwJzI4LjMiTiAxN8KwNDgnNTUuMSJF!3b1!8m2!3d43.341183!4d17.815308!3m4!1s0x0:0x0!8m2!3d43.341183!4d17.815308?utm_medium=s2email&shorturl=1

Here is my log ....

https://app.airdata.com/share/gYDVQi

Here is the video of the incident...I have flown the drone many times and have experience with it.

There is a small chance the .DAT log file will have recorded location data past the point where the .txt ends. Take a look at this posting  to see how to retrieve the .DAT log file
https://fpvdronepilots.com/threads/dat-available.4225/#post-35016
The name of the .DAT you are looking for is
FLYxxx-097-xxxxxxxxxxx.DAT

I'm not sure if you can attach it to a post. If not, you'll need to use a public sharing site like Dropbox or GoogleDrive

BudWalker Posted at 9-29 10:26
There is a small chance the .DAT log file will have recorded location data past the point where the .txt ends. Take a look at this posting  to see how to retrieve the .DAT log file
https://fpvdronepilots.com/threads/dat-available.4225/#post-35016
The name of the .DAT you are looking for is

Hey Bud,

I got the Dat file and checked it with the apps you sent me a link to and the location I came up with was this: https://www.google.com/maps/place/43%C2%B020'27.2%22N+17%C2%B048'55.4%22E/@43.3410005,17.8153571,186m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d43.340891!4d17.815384

Did you get the same? Here is the .DAT file

https://www.dropbox.com/s/19gtna4pgo1pz00/FLY085-097-20210927144720.DAT?dl=0

Hello there. I am sorry to read and to know what happened to your DJI FPV and thank you for reaching out. Since this unfortunate event happened I would recommend for you to contact our DJI Support Team at https://www.dji.com/support?site=brandsite&from=nav for further assistance with regards to this matter. We will do there best to help you and give out the best resolution for the said issue. Again, I am sorry and thank you.

It wasn't there because someone else found it and decided to.keep it.  Assuming you did not get to the crash site fast enough

fansf0572733 Posted at 9-30 07:54
It wasn't there because someone else found it and decided to.keep it.  Assuming you did not get to the crash site fast enough

Well, I had to find the location first...I doubt anyone took it, maybe some kids. In the video, it looks like it crashed, while the sensors are showing that it landed at a parking lot.

If you lose signal and the drone goes into normal mode, and it doesn't return home. What happens? Does it start to look for a place to land? is that what it normaly does?

djiuser_3shdsaQN6yFC Posted at 9-29 15:38
Hey Bud,

I got the Dat file and checked it with the apps you sent me a link to and the location I came up with was this: https://www.google.com/maps/place/43%C2%B020'27.2%22N+17%C2%B048'55.4%22E/@43.3410005,17.8153571,186m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d43.340891!4d17.815384

I got almost the same position that you did. The real question is what happened after the down link was lost. A switch to Manual mode was made at 64.667 secs. The .DAT indicates that a switch back was made just 0.2 secs later. But, the .txt indicates that FPV continued in M mode. Looking at the attitude data it appears that the FPV was flying in M mode. In fact, the FPV seemed to be ignoring the control stick inputs and proceeding pitch up 35° to 70° and roll CW 33° to 43°. THere was not enough throttle to keep the FPV from descending.

Assuming that the FPV kept this attitude and throttle setting the trajectory can be computed. The FPV was 43 meters AGL and descending at 9.2 m/s. If it weren't for the buildings impact would have occurred 4.76 secs later. The FPV was moving 27. m/s. Again, if it weren't for the buildings the FPV would have travelled another 132 meters.
The yellow line shows the possible impact sites.

BudWalker Posted at 9-30 13:51
I got almost the same position that you did. The real question is what happened after the down link was lost. A switch to Manual mode was made at 64.667 secs. The .DAT indicates that a switch back was made just 0.2 secs later. But, the .txt indicates that FPV continued in M mode. Looking at the attitude data it appears that the FPV was flying in M mode. In fact, the FPV seemed to be ignoring the control stick inputs and proceeding pitch up 35° to 70° and roll CW 33° to 43°. THere was not enough throttle to keep the FPV from descending.

Assuming that the FPV kept this attitude and throttle setting the trajectory can be computed. The FPV was 43 meters AGL and descending at 9.2 m/s. If it weren't for the buildings impact would have occurred 4.76 secs later. The FPV was moving 27. m/s. Again, if it weren't for the buildings the FPV would have travelled another 132 meters.

Thanks man for helping! Thanks alot.

There is no way the drone was in Manual as it switched to normal mode long before.

the FPV was 43 meters AGL and descending at 9.2 m/s. If it weren't for the buildings impact would have occurred 4.76 secs later.

If it was at 43meters and falling 9m pr sec I don't think it would have flown far, as the buildings are aprox 20-30meter in height. So i suspect its somewhere in the trajectory you suggested. I will have another look tomorrow.

By the way, did you watch the youtube video? In the video it looks like it got hit by something and crashed....but i doubt that it crashed because the sensors indicated that continued flying.

I hope I find the damn thing...if I do I would love to buy you a beer and give you a donation

All the best,
Miran

djiuser_3shdsaQN6yFC Posted at 9-30 15:16
Thanks man for helping! Thanks alot.

There is no way the drone was in Manual as it switched to normal mode long before.

You're right it switched out of Manual at 40 secs. But, there was a momentary mode switch at about 64 secs that coincided with the start of the incident. It's labelled as FPV mode but I suspect that it might actually be Sport mode. I'll do a test with my FPV.

But, regardless, when that momentary mode switch occurred the motors started being commanded much higher with no input from the control sticks. The lateral velocity dropped but then increased reaching 27 m/s. The descent rate increased to 9.2 m/s and was still increasing when the .DAT stopped recording.



I don't see any data that indicates that it landed in the parking lot.

A mid air collision would have shown up in the accelerometer and/gyro data - no indication was seen.

I looked briefly at the video. I couldn't really see what was happening. Maybe the abrupt attitude change occurred when the motors were abruptly commanded higher.

I did a test with my FPV. Sport Mode gets labelled as FPV mode in the log files. GPS_ATTI means Normal mode. When the pilot switches to Manual the FPV first changes to PreManual and then Manual once the trottle is set correctly.

Anyway, in this case the FPV appeared to be stuck pitch up 35° to 70° and roll CW 33° to 43°. At those pitch angles not enough vertical thrust can be obtained to keep it from descending. That's probably why the motors were commanded to 100%.


I think DJI engineering would want to see the .DAT log file. Seems clear that this is a hardware issue, or possibly a firmware issue.