I was on site with a colleague whose Phantom 4 Lost GPS Signal and then almost similtaneously lost radio link with the controller.The drone was at the start of a Litchi Mission to fly a circuit whilst recording video, it lost contact when 1/2 way to the mission starting point.

We have reviewed the flight logs and searched the last reported location and the path to the starting point with no success.

There are no obvious problems in the CSV file
We have the flight DAT file as well & are curious if there is a way of reviewing it to get a better idea of the problem.
At this stage we are assuming it went into hover in ATTI mode and was carried off by the wind.

Hello there MinerDetails. I am sorry to read and to know what happened to your DJI Phantom 4. Since this unfortunate incident happened and you have lost the said DJI drone. I would recommend for you to contact our DJI Support Team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We have a team that will do there best to help you and give out the best resolution for the said issue. Again, I am sorry for your loss and thank you.

Losing GPS is not normal up in the air and losing signal around the same time is odd.

Post your Litchi CSV file and I'll have a look to see if it gives any clues.
It would also help if you can post a screenshot of the Litchi mission to where the drone would have been headed and what the terrain is like.

DJI Stephen Posted at 5-16 20:00
Hello there MinerDetails. I am sorry to read and to know what happened to your DJI Phantom 4. Since this unfortunate incident happened and you have lost the said DJI drone. I would recommend for you to contact our DJI Support Team at https://www.dji.com/support?site=brandsite&from=nav for further assistance. We have a team that will do there best to help you and give out the best resolution for the said issue. Again, I am sorry for your loss and thank you.

The DJI support team won't be much use as he lost the drone while using a 3rd party app and doesn't have any DJI flight data records.

Thank you for the replies, I was not hopeful of much from DJI the main interest was to find out what the drone might have done after the loss of signal, we lost sight of it when looking away from the drone to the screen to see what was going on.
Please find attached the Litchi CSV and the DJI .DAT file from the connected IPhone, and a screengrab of the mission. As far as we could determine the drone was at cruising speed towards the starting point of the mission with plenty of battery. There was a 15kph breeze from the West at the time - we have flown a PIX4d Vertical capture mission downwind from the area in the hope of seeing something in the images , with no joy.No joy with the DAT file - 3.7MB too big to zip and post.

And the CSV I hope,

There are no obvious problems in the CSV file.
The data file doesn't give much to go with, but helps to eliminate some possible causes  for loss of teh drone.
It ends with the drone in stable flight at 8 m/s, heading east and was just north of the workshop.
The battery was in good condition and freshly charged with all cells >4 volts.
Altitude was sufficient that loss of signal behind an obstacle can be ignored.
Pitch, roll and yaw data give no indication of any collision.

At this stage we are assuming it went into hover in ATTI mode and was carried off by the wind.
There's no reason that the Phantom should have lost GPS, but if it did the control signal would have been maintained.The Litchi data file doesn't show what the drone was programmed to do if signal was lost during the mission.
If  it was on the Litchi default setting, the drone should have continued  the mission which would take around the circuit to waypoint 13 and  whatever end of mission instruction was set.
If if you had it set to RTH on losing signal, you'd have had it come home.

The only logical conclusion is that signal was lost because of a total, sudden loss of power which prevented the Phantom completing the mission or returning home.
Given the height and speed of the drone, a rough estimate of where it may have crashed is approx 50 metres east of the last reported location.
This is short of the haul road around the head of the arrow.
If you didn't already, I'd concentrate a search for about 25 metres around that point.
Good luck

Yes to all of the above, I was hoping the .dat file might give more information on the failure, we couldn't see any problems in the .csv file, the controller did report GPS Signal Lost, and then the signal was lost.

MinerDetails Posted at 5-18 11:31
Yes to all of the above, I was hoping the .dat file might give more information on the failure, we couldn't see any problems in the .csv file, the controller did report GPS Signal Lost, and then the signal was lost.

the controller did report GPS Signal Lost, and then the signal was lost.
Unfortunately Litchi recorded data is not as good as DJI data and doesn't show all screen messages.
I would wonder about the GPS loss message.
It doesn't make any sense.

Where you were flying, there's no real reason you should be losing either GPS or control signal.
I could accept that the drone lost GPS or lost control signal, but losing both at the same time is a bit hard to believe.

I wonder if the GPS message was a false indication that came through on losing the drone when power was lost?

That was my best guess - a short or failure on the GPS board taking out the radio and then the motors - but as to where it landed ?? we walked the area thoroughly with no result.

MinerDetails Posted at 5-18 00:36
Thank you for the replies, I was not hopeful of much from DJI the main interest was to find out what the drone might have done after the loss of signal, we lost sight of it when looking away from the drone to the screen to see what was going on.
Please find attached the Litchi CSV and the DJI .DAT file from the connected IPhone, and a screengrab of the mission. As far as we could determine the drone was at cruising speed towards the starting point of the mission with plenty of battery. There was a 15kph breeze from the West at the time - we have flown a PIX4d Vertical capture mission downwind from the area in the hope of seeing something in the images , with no joy.No joy with the DAT file - 3.7MB too big to zip and post.

There is a small possibility the .DAT will provide more info. Can you use a public sharing site like Dropbox or GoogleDrive to share it?

BudWalker Posted at 5-19 05:29
There is a small possibility the .DAT will provide more info. Can you use a public sharing site like Dropbox or GoogleDrive to share it?

There is a DJI Filightlog recorded when using Litchi.
In your devices internal storage goto folder DJI > com.flylitchi.litchi > FlightRecord > DJIFlightRecord_ (date of flight, time of flight).txt
You will have to upload this log here or to PhantomHelp Log Viewer to decode.
This log has extra information not shown in Litchi Flight Log
Had a look at your log, Phantom flying towards 1st waypoint in good health when data ends. You've searched surrounding area and not found anything.
Possible Litchi glitch and drone just kept flying on in same direction ignoring mission. Sorry for your lose.

Pleomax Posted at 5-21 10:38
There is a DJI Filightlog recorded when using Litchi.
In your devices internal storage goto folder DJI > com.flylitchi.litchi > FlightRecord > DJIFlightRecord_ (date of flight, time of flight).txt
You will have to upload this log here or to PhantomHelp Log Viewer to decode.

There is a DJI Filightlog recorded when using Litchi.
Are you sure about that?
It would have made things much easier analysing Litchi flights for the last few years if it's true.
But there's no >com.flylitchi.litchi folder anywhere in either of the tablets I fly with.

Possible Litchi glitch and drone just kept flying on in same direction ignoring mission
And a mysterious loss of signal at the same time as the unexplained (and never seen before) Litchi glitch?
That requires too much coincidence for it to be considered.

Labroides Posted at 5-21 16:20
There is a DJI Filightlog recorded when using Litchi.
Are you sure about that?
It would have made things much easier analysing Litchi flights for the last few years if it's true.

100% sure,  use Litchi exclusively,  last flights 18/05/21. Watch video on where files are, I'm sure I'm not the only person who knows this. As for the Litchi glitch, just as plausible as your scenario and even more likely as drone not recovered.

Pleomax Posted at 5-22 04:38
100% sure,  use Litchi exclusively,  last flights 18/05/21. Watch video on where files are, I'm sure I'm not the only person who knows this. As for the Litchi glitch, just as plausible as your scenario and even more likely as drone not recovered.

As for the Litchi glitch, just as plausible as your scenario and even more likely as drone not recovered.
Your scenario needs:
1.  A litchi glitch (which would be a rare thing)
   and
2. An unlikely loss of signal at the same time.
The likelihood of both happening and at the same time is pretty slim.
The chances of a total loss of power would be something like 100 times more likely.

100% sure,  use Litchi exclusively,  last flights 18/05/21
Maybe it's a recent thing, I haven't had a need to use Litchi for about 18 months.
I'll have to try a test Litchi flight and see if it will now.
It would be a big improvement as the Litchi csv is horrible for analysing.

Labroides Posted at 5-22 06:34
As for the Litchi glitch, just as plausible as your scenario and even more likely as drone not recovered.
Your scenario needs:
1.  A litchi glitch (which would be a rare thing)

Upload a few logs for you to look at, earliest Dec 2018.

https://drive.google.com/drive/f ... VJjtM4y?usp=sharing

Labroides Posted at 5-22 06:34
As for the Litchi glitch, just as plausible as your scenario and even more likely as drone not recovered.
Your scenario needs:
1.  A litchi glitch (which would be a rare thing)

Did you have a look at logs I've uploaded and if so what's your conclusion?

Pleomax Posted at 5-24 07:01
Did you have a look at logs I've uploaded and if so what's your conclusion?

You have DJI-style flight records from Litchi