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Lost connection close to my house and it's still lost

Joined
Sep 23, 2018
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#1
My drone disconnected from my app so I restarted it and nothing. Then I restarted my controller and nothing. I walked to where the drone should have been and nothing. I'm pretty sure it's on a roof or in a yard. It was 200 ft up when I lost connection with 70%. With the log uploaded can anyone help me figure which doors to knock on? Attached is my flight log. I searched the open field with my controller on trying to reconnect.
 

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AeroJ

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#2
Ouch. Sorry for your loss.

The log just stops at 7:36:07 with 70% power, although you were drifting in Atti mode having lost GPS (presumably due to WiFi interference) at 7:02, which never returned.
Just before it loses GPS there is a YAW ERROR that persists for some 30 seconds, and you get WEAK SIGNAL and MAG FIELD INTERFERENCE warnings during that period, though GPS is already down, so they shouldn't make additional difference.

Why the log, and presumably power just stops when it does, at 244ft, I don't know. But assuming it dropped like a stone at those coordinates, then you will likely find it in pieces in the back yard of the second house on the left down Coral Ridge Drive, where the red arrow is below...

MP down.JPG



Good luck with the search and rescue mission... let us know how you go.
 

SpinItUp

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#5
Questions are
did you still have visuals on the craft
did you still operate RC with input from the sticks and such (which would affect the destination as to where it went/is)
This happened to me but I still had control of the craft as it was in VLOS
 
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#6
I did have connection with the controller for a minute or so but I made sure to not move it at all since I couldn't see it as i was walking towards the area i thought it was. By the time i got there i had no connection(my own fault, i tried restarting the controller).
 
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#8
At least you assumed that as correct... wouldn't it then RTH?
I was hoping it would RTH but nothing. ITT had 70% which was more than enough to get back and RTH was set at 30 meters plenty high enough to get over houses. If my RTH was set to my driveway, what's the area it would have landed if it did RTH? I assumed my driveway/ front yard but is it an area like 15ft?
 

SpinItUp

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#9
roof.jpg

I have no experience of restarting my controller and what happens in this situation.
The last contact shows you over the corner of the roof of that house.
This is where another drone or video would be useful
 

SpinItUp

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#11
I'd start with the roof of the house on the other road then roof2.jpg roof3.jpg

it looks like you may have input a slight move towards your home point which put it on top of the roof as depicted by the curve at the end of the plotting graphic curve.jpg

Or did it hit the gable end of the house?

Flight mode changed to P-GPS on the last shown connection, not in ATTI as depicted by the Green not Red line
ATTI between the arrows shown here then it gets GPS again just before your loss
Skitch (9).png

You had the Active track Optimized almost at the Home point but then lost your subject and all **** seems to break loose after that ...what were your trying to accomplish?
ATTI kicked in twice shown by the red bands towards the last shown P-GPS.
All the other red short bands show the other Errors (if I was getting that I would start to question 'Should I really be flying'?) errors_modes.jpg
Plus your rather close to an airfield as the Warnings are showing
 
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#12
I'd start with the roof of the house on the other road then View attachment 47642 View attachment 47643

it looks like you may have input a slight move towards your home point which put it on top of the roof as depicted by the curve at the end of the plotting graphic View attachment 47644

Or did it hit the gable end of the house?

Flight mode changed to P-GPS on the last shown connection, not in ATTI as depicted by the Green not Red line
ATTI between the arrows shown here then it gets GPS again just before your loss
View attachment 47646

You had the Active track Optimized almost at the Home point but then lost your subject and all **** seems to break loose after that ...what were your trying to accomplish?
ATTI kicked in twice shown by the red bands towards the last shown P-GPS.
All the other red short bands show the other Errors (if I was getting that I would start to question 'Should I really be flying'?) View attachment 47658
Plus your rather close to an airfield as the Warnings are showing
I was testing active track then switched to regular flight mode. As soon as I saw the error I went into my app setting to ensure RTH height was set at 30, when I clicked our I had no connection. Only my third day owning it, I was still learning and didn't think 2 blocks away I'd lose my $1000 drone. Unfortunately now I know all the shortfalls of the find my drone app/DJI help and what to do in a disconnect situation. I just hope someone finds it and I get it back.
 
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Tesadorn

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#15
Sorry for your loss... If you do continue in the hobby spend some time reading and practice flying up close visually... I downloaded and looked at the log and I can tell you... I would have landed that thing 4-5 times based on the errors I saw... Compass errors ALWAYS worry me... Also MAG Interference does as well... Looks like you could have gotten it back up until the bitter end..
Hope you find it and are able to repair... If not don't despair!@ Plenty of educations cost more!@ Rc hobbies almost always resort in spending lots of money! :) Also.... Why so many refrigerators? :)
 
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#16
Update: still no luck finding my drone and nobody has called saying they found it. There is good news however, DJI emailed me saying they reviewed the data and it looks like a warranty issue took it down. They are sending me a new drone(happy dance). I still hope to find the original at least to recover the video and see what the **** happened. This forum is awesome and you guys are like some detectives.
 
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SpinItUp

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#17
happy days
Never of thought, they would do that
Increase the reward, a 100bucks don't seem enough

This is why I set the App to cache the media on my device
 
Last edited:

sar104

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#18
The problem figuring out where it may have ended up is that it was switching between ATTI and P-GPS towards the end. In P-GPS the disconnect is going to cause it to attempt to RTH, although the compass errors were compromising its ability to navigate. In ATTI mode loss of signal triggers immediate autoland.

Since it did not RTH we can assume that either it did end up in ATTI mode or it blundered around in some combination of GPS mode and ATTI mode until the battery reached the autoland level, at which point it will have landed. In that scenario it could be virtually anywhere within a couple of miles. Not useful.

At the other extreme, if it went back into ATTI without trying to RTH, then it will have made a fairly well-defined descent from the last known point. Based on the aircraft speed in ATTI mode, the wind was approximately 17 m/s out of the SSE at 75 m altitude, and so in ATTI mode it would have descended at 3 m/s drifting NNW on the wind at around. From 75 m altitude the descent would have taken around 25 s, and so it could have traveled 425 m to the NNW, although likely less since the wind speed decreases with altitude (AirData suggests it was around 5 m/s at 30 m). In between is the possibility that it did make some progress back towards home but at some point dropped back to ATTI and again drifted NNW before landing.

There is some basis for guessing that it might, initially, have made RTH progress back towards the home point. Looking at the inertial data compared to the IMU data the agreement was fair until 391 seconds, at which point the yaw errors caused the inertial data to become worthless:

2018-09-23_[10-27-10]_02.png

But looking at the final stage of the recorded flight when the FC switched back to P-GPS, it does successfully halt the aircraft's drift, implying that the yaw error is not impeding navigation at that time.

2018-09-23_[10-27-10]_01.png

Those latter two scenarios are shown on the map below as the green shaded area, which goes out to the full 425 m distance.

screenshot211.jpg
 

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