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What happened to my drone? Lost connection at 120 meters

Bogrisch

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Hi

This incident happened a few days ago and i cant really figure out what caused this.

I have just descended my drone from max altitude in sport mode down to 120+ meters. I hovered there for a short while and looked around with the drone and was just about to fly the remaining 600 meters home. Before i got the chance to go home i lost connection to the drone about 2-3 times for about 1 second each time and the last time i did not get connection established again. I waited for a while for it to return to home which I believe i had the rights settings as I use to have. It did not come and i tried to restart the app and controller but was not able to establish connection with the drone.

I used the find my drone feature and took off with my car there and found it on a trashcan (somebody put it there) and thought everything went well i soon found out that both front leg arms were broken, one prop and 1 landing gear leg and it had dirt on it and were broken so I am sure it landed on the field 20 meter from there where the app last had connection. The battery showed 2/4 LED-dots and was turned on when i arrived.

I am sure I did not turn off the recording but it stopped mid air. When i looked in black box the last thing that i can see was that the engines where running at around 120+ meters and i cant find any information past that point. Everything seemed normal to me.

I started the drone again at home without props and the first time i could not move gimbal. Then i turned it on again (the first time without memory card) and it worked. Everything seemed fine.

If it fell from 120 meters, can it even survive?

May this be a battery malfunction?
If not, why did the drone loose connection?
Why did it not fly home?

// Bogrisch
 

InvisibleName

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I’ll be the first - you need to post your flight data for anyone to even start to try & understand what happened
 
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gnirtS

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Upload the .txt file off the controller. Other software can go through that a bit easier.
 

cornz

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Hi

This incident happened a few days ago and i cant really figure out what caused this.

I have just descended my drone from max altitude in sport mode down to 120+ meters. I hovered there for a short while and looked around with the drone and was just about to fly the remaining 600 meters home. Before i got the chance to go home i lost connection to the drone about 2-3 times for about 1 second each time and the last time i did not get connection established again. I waited for a while for it to return to home which I believe i had the rights settings as I use to have. It did not come and i tried to restart the app and controller but was not able to establish connection with the drone.

I used the find my drone feature and took off with my car there and found it on a trashcan (somebody put it there) and thought everything went well i soon found out that both front leg arms were broken, one prop and 1 landing gear leg and it had dirt on it and were broken so I am sure it landed on the field 20 meter from there where the app last had connection. The battery showed 2/4 LED-dots and was turned on when i arrived.

I am sure I did not turn off the recording but it stopped mid air. When i looked in black box the last thing that i can see was that the engines where running at around 120+ meters and i cant find any information past that point. Everything seemed normal to me.

I started the drone again at home without props and the first time i could not move gimbal. Then i turned it on again (the first time without memory card) and it worked. Everything seemed fine.

If it fell from 120 meters, can it even survive?

May this be a battery malfunction?
If not, why did the drone loose connection?
Why did it not fly home?

// Bogrisch
Somewhere on the site (im new here too) is a link where you can upload your flight logs and some kind folks on here will pick it apart for you to try and see what happened.
 
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gnirtS

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On android its in the DJI Go folder there are sub folders for flight record with a .txt file for each flight. It's that we need.

On apple you probably have to sacrifice a virgin to the god of steve jobs and get written permission off tim cook and pay $400 to get access to it (in other words, its there but not as easy to get).
 

Bogrisch

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On android its in the DJI Go folder there are sub folders for flight record with a .txt file for each flight. It's that we need.

On apple you probably have to sacrifice a virgin to the god of steve jobs and get written permission off tim cook and pay $400 to get access to it (in other words, its there but not as easy to get).
Haha! Glad I did not have an Apple device.. Here is the link to Flight Record .txt file:

Dropbox - DJIFlightRecord_2018-08-01_[21-17-36][1].txt
 
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gnirtS

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Thats an odd one, as you say.
Im seeing a few level 1 wind warnings and one level 2 very high wind warning but nothing else.
The last line just says avoid blocking antenna then it stops instantly, within a 10th of a second.

If it wasnt for that one "avoid blocking the antenna" id wonder if a battery shook itself loose (it was windy). If the winds were very high (level 2 warning) chances are it might not make it home against the wind in the event of a lost signal though.

Were there any trees or buildings that might have got in direct line of sight between you and the drone? That can cause an immediate signal drop.

I'll look more a bit later,
 
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Bogrisch

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Thats an odd one, as you say.
Im seeing a few level 1 wind warnings and one level 2 very high wind warning but nothing else.
The last line just says avoid blocking antenna then it stops instantly, within a 10th of a second.

If it wasnt for that one "avoid blocking the antenna" id wonder if a battery shook itself loose (it was windy). If the winds were very high (level 2 warning) chances are it might not make it home against the wind in the event of a lost signal though.

Were there any trees or buildings that might have got in direct line of sight between you and the drone? That can cause an immediate signal drop.

I'll look more a bit later,
Ye I got some warnings about the wind when I was flying at max altitude but I never felt the wind for my self at ground level. It was only 600m to home point and the battery were around 40-50% if that is true. I thought about that with the battery maybe shook itself loose. But it was turned on when I got there but the motor was not running. Yes there were trees and houses in the way but the drone were still about 120+ meters above the ground so I believe it should not have a huge impact on the signal. Maybe it was because I put the controller on the ground and sitting down while descending (lack of patience). When I lost signal i stood up and tried to get signal back but failed. I were a bit stressed and tired because there was a beautiful sunset and I were going to work early in the morning so maybe did not connect the battery properly.. Thank you I appreciate that.
 

gnirtS

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Actually can you confirm the RC lost connection or just the app?
 

Bogrisch

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Actually can you confirm the RC lost connection or just the app?
The RC lost connection. I tried press the return to home button and it started to beep but had no connection. I am pretty sure the app was still ok.
 

gnirtS

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OK, what i have found with mine is occasionally the app will crap out OR i'll knock a cable and this "freezes" the RC - it is unresponsve, the data on it doesnt update. During this time the drone normally initiates a RTH and then the RC recovers after 10 seconds or so.
But that appears not to be the case here.

The drone was still turned on when you recovered it? The DAT file in that case should show its actual descent and the voltages.
 

Bogrisch

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It was turned on and the light at the back of the drone were flashing yellow fast. Did not manage to see any data from the .DAT file around the point were the connection were lost but I have only used the software once. Maybe the people who found it also turned it on? But I had the remote connected to my phone all the way to the crash site and it did not connect with the RC.
 

gnirtS

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The .DAT will see if its been powered up (it stored an event). If it was on all the way it rules out a loose battery.
 

Bogrisch

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The .DAT will see if its been powered up (it stored an event). If it was on all the way it rules out a loose battery.
I have tried to use Data Viewer in DJI Assistant 2 to see if I can figure that out. When the drone is approx 280 meters above sea, and battery percentage is at 43%, voltage 11,3 V and current 6,6 A. Then there is no more data after that. I cant find it anyway. I cant get the program to select to show data from when motors start and finish when they are turned off. And I do not know why.
 

Tanman5050

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Hello everyone I am new to this but I have heard online that people have been shooting at 2.7k 60 FPS but my drone only offers 2.7k at30 FPS I am using an iPhone with controller and need help thanks
 

Bogrisch

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Hello everyone I am new to this but I have heard online that people have been shooting at 2.7k 60 FPS but my drone only offers 2.7k at30 FPS I am using an iPhone with controller and need help thanks
Mavic Air: 2.7K: 2720×1530 24/25/30/48/50/60p
Mavic Pro: 2.7K: 2720x1530 24/25/30p
 

gnirtS

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I have tried to use Data Viewer in DJI Assistant 2 to see if I can figure that out. When the drone is approx 280 meters above sea, and battery percentage is at 43%, voltage 11,3 V and current 6,6 A. Then there is no more data after that. I cant find it anyway. I cant get the program to select to show data from when motors start and finish when they are turned off. And I do not know why.
That sounds like a power issue if the data just stops logging with no errors or events. Like a loose battery or similar.
 

Bogrisch

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I agree. I Probably did not connect the battery properly or something is wrong with the battery. Can't really think of any other explanation. I am grateful nothing bad happened to any person, animal or property.

Thank you gnirtS for your effort and time helping me out. I appreciate.

// Bogrisch
 

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