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Lost my Mavic in a very tough area, please help me find it. (RC blackbox files)

Marche777

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Aug 3, 2019
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Age
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Yesterday i lost my Mavic Pro...
I'm really sad because i think it was my fault, but anyway, now i just have to find it.
I have the last recorded position from the DJI GO app but it was still at 200+meters high and it was at the very edge of a precipice and then the app crash and i don't have any other info. Last coordinates ( 440408513,11.319304 )

The rc was still going while the Mavic landed/crash and i saw that the last altitude was about -75meters (i took off from the hills so the drone now must be +/- from my take off altitude) and so i think it goes down the cliff and the last recorded position is not true.
The area is very tough with lots of very high cliffs and precipices so the research is also very dangerous.
Online i discorver the possibility to extract other data from the remote and i save the blackboxfile hoping this will help me find it, but i don't know how to open them.
I attached them for you here --> ( cp_assert.log and 26 more files )
This afternoon i will go there starting to find it.
Any help is really appreciated!
Thank you and sorry for my unperfect English, i'm Italian.

@sar104 @msinger @BudWalker
 
Welcome to the forum, sorry your first post is a help me find my drone. Seems you have done your homework and have 4 of the top data analysts on board to help. I will just sit back and watch them work their magic. Again welcome and I hope you find it.
 
Your English is very good.
Here are some instructions to find the files that are needed.
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.
Thank you guys, i don't know how to express my gratitude to you all.
I just passed my whole day with 3 of my friends in one the most impervious place of my life trying to find it without any sure landing spot, it's a very very deep forest with huge cliffs and no paths, i'm litteraly destroyed. Now that i saw the place I CAN SAY FOR SURE THAT WITHOUT A VERY PRECISE LANDING SPOT IT IS IMPOSSIBLE TO FIND.
And @Meta4, i already tried to use that website to upload the fatal file but it says internal server error and because of the dji app crash while the drone was still at 300m i think it is useless to upload any fly log.
I also check the precise location of the last recorder point in the app, coordinates (440408513,11.319304) at 300m high, and it's the very edge of a 200 meters cliff. But we didn't find it.
And yes, it's my first post also because my i only had the mavic for two days...
This is very very frustrating...
 

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@Marche777, don't underestimate the knowledge in this group. Many drones have been found with their help, even lost in heavily covered terrain. I have seen sar104 walk people on this forum within feet of a drone falling powerless from the sky. Don't give up, spend your time finding a way to post the info needed and they will guide you with their knowledge of Google earth and wind speed. All is not lost, good luck.
 
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i already tried to use that website to upload the fatal file but it says internal server error and because of the dji app crash while the drone was still at 300m i think it is useless to upload any fly log.
It's not possible to tell what happened or where the drone might be without data.
Can you post the .txt file(s) for us to look at?
 
It's not possible to tell what happened or where the drone might be without data.
Can you post the .txt file(s) for us to look at?
Hi Meta4, sure, i'm 100% at your disposal. Where can i find these .txt files? I already attached a download link with all the files i've found inside the rc.
Do you need some files from the mobile? Just tell me what you need, i'm not very practiced. Sorry
 
Hi Meta4, sure, i'm 100% at your disposal. Where can i find these .txt files? I already attached a download link with all the files i've found inside the rc.
Do you need some files from the mobile? Just tell me what you need, i'm not very practiced. Sorry
The file(s) will be in your phone or tablet.
The link in post #2 gives instructions to find them.
 
@Marche777, don't underestimate the knowledge in this group. Many drones have been found with their help, even lost in heavily covered terrain. I have seen sar104 walk people on this forum within feet of a drone falling powerless from the sky. Don't give up, spend your time finding a way to post the info needed and they will guide you with their knowledge of Google earth and wind speed. All is not lost, good luck.
I really need your help and knowledge.
New clues are foundamental to start the reseaches again. I'm waiting for someone able to help me reading the telemetry.
Hope it's not all lost.
 
Ok i found them. Is it what you need?
 

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It's not completely clear what happened at the end of that flight. The aircraft went into autolanding at 817 seconds when the battery level dropped below the SMART_BATTERY_landBattery level:

Battery.png

The puzzle is why the connection dropped, because the aircraft still had good line of sight to the home point, and there were no lost data packets leading up to that. There were a number of battery errors however, of a kind I haven't seen before:

821.900 : 44529 [L-BATTERY]cap2_flg == 1 smart_capacity_level2_status == FALSE!

I'm not sure what that means, but it may not be good, and the sudden disconnect may have been due to an unexpected shutdown.

Anyway, there are really two possibilities:
  1. It continued with autolanding, in which case it will have ended up pretty much directly below the last recorded point - the yellow pin in the image below. That should be pretty accurate - probably within 10 meters.
  2. It shutdown and fell to the ground. In that case it will have been blown laterally by the wind, which was around 14 m/s (30 mph) out of the west at its last recorded height. The descent estimate in that case has potential errors due to unknowns in the wind speed as a function of height, but assuming a linear decrease to ground level, gives a crash point indicated by the green pin. I'd not be confident of that trajectory to better than around 30 meters.
screenshot213.jpg
 
Anyway, there are really two possibilities:
  1. It continued with autolanding, in which case it will have ended up pretty much directly below the last recorded point - the yellow pin in the image below. That should be pretty accurate - probably within 10 meters.
  2. It shutdown and fell to the ground. In that case it will have been blown laterally by the wind, which was around 14 m/s (30 mph) out of the west at its last recorded height. The descent estimate in that case has potential errors due to unknowns in the wind speed as a function of height, but assuming a linear decrease to ground level, gives a crash point indicated by the green pin. I'd not be confident of that trajectory to better than around 30 meters.
Beat me to it, that looks good
But what do you make of the VPS data at 11:47, 11:55 and 12:23?
The drone was much higher than any terrain at the time (which was a big part of the problem as the wind at that level was too strong for RTH at that distance).
 
Beat me to it, that looks good
But what do you make of the VPS data at 11:47, 11:55 and 12:23?
The drone was much higher than any terrain at the time (which was a big part of the problem as the wind at that level was too strong for RTH at that distance).

I'm sure that those are spurious - they correspond to significant negative pitch and roll.

vps.png
 
Now our new Italian Brother, rest up and search exactly within that 90 feet radius from the pin. Focus in the center first and I hope you're successful, I look forward to more pics of your beautiful part of the world.

Thank you two for your time spent helping others, I feel this young man's pain after only having the craft for two days.
 
Hi guys,
Sorry, yesterday after the last message i go to bed, here it was 3:00AM, hoping in a better awakening...
First of all thank you @sar104 for the great analysis you have done for me but did you consider that when the app disconed the rc was still connected and, ultil the end, i was able to read the fly telemetry on the remote lcd screen?
For me, it could be a crucial point of the analysis of where the drone could be for three main reason.

1) if the drone had shut down, wouldn't the controller signal also fall out?
2) The last altitude read was like -75 meters below the take off point so, if this this data can be taken as true and certain, the drone now must be at an altitude of 230/240 meters. So we can certainly exclude that it is above the ravine, where the last position was recorded, because this point is higher than the home point.
3) While i tried multiples times to reconnect the mobile, but there was no way to get it work again, the controller signal remains till i shut it down and other than the -75m altitude it also showed that the propellers were still going.

That said don't you think that the "blackbox" data inside the rc are the ones to study?
What should i do? I may try to contact DJI...
The pain is real
 
Hi guys,
Sorry, yesterday after the last message i go to bed, here it was 3:00AM, hoping in a better awakening...
First of all thank you @sar104 for the great analysis you have done for me but did you consider that when the app disconed the rc was still connected and, ultil the end, i was able to read the fly telemetry on the remote lcd screen?
For me, it could be a crucial point of the analysis of where the drone could be for three main reason.

1) if the drone had shut down, wouldn't the controller signal also fall out?
2) The last altitude read was like -75 meters below the take off point so, if this this data can be taken as true and certain, the drone now must be at an altitude of 230/240 meters. So we can certainly exclude that it is above the ravine, where the last position was recorded, because this point is higher than the home point.
3) While i tried multiples times to reconnect the mobile, but there was no way to get it work again, the controller signal remains till i shut it down and other than the -75m altitude it also showed that the propellers were still going.

That said don't you think that the "blackbox" data inside the rc are the ones to study?
What should i do? I may try to contact DJI...
The pain is real

OK - so the sudden end to the logged data was because the app crashed or disconnected? If that is the case, and if you continued to fly the aircraft laterally (right stick) using the remote, then unfortunately there will be no stored data on its subsequent flight. The RC does not contain any useful publicly readable files, although DJI might be able to help.
 
FYI, if the Remote was still connected and you say it was, you were still in control of the drone. The Mavic as you've mentioned shows position of the drone to the remote, you should have flown the drone back to you.

If it was in a auto landing due to low battery, you should have walked to its location ( if possible ) before the crafts battery went completely dead.

I am sorry but you should have understood the operation of your drone more before taking flight. Any stick inputs as sar104 has mentioned are not recorded it the Flight Logs that he is able to analyze. Even while auto landing the operator stills had some limited control of the drone while landing.

Sorry
 
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