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I have lost my DJI Mavic Pro
3221 27 2017-5-23
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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Three days ago.. I was flying in the mountains here in switzerland.

After a distance of maybe 4300m flying in sport mode (!) I lost the connection to the drone (battery 68%), because a mountain was between the drone and the remote controller.
The mavic startet RTH with direct way home, and not reverse path of flyght. so on the way home it hit eventually the mountain. I haven't seen my drone again since then.

I noticed, that even within sport mode, the flight speed while RTH does not exceed around 30km/h. So why is obstacle avoidance not working with that speed?

I do not understand, why a hightech drone on a RTH flight home without connection to the remote controlle and with a flight speed of 30km/h does not obstacle avoidance and flies into the mountain... or.. why the drone does not reverse exactly the flight path while RTH?

Now the drone is gone and ther is no chance to climb the mountain to get my mavic.. I've tried that the day after. In this case I can't use my DJI Care Refresh... :-(

last flight of my dji mavic pro

last flight of my dji mavic pro
2017-5-23
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Lok Mavic
lvl.4
Flight distance : 1486660 ft
United Kingdom
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"I do not understand, why a hightech drone on a RTH flight home without connection to the remote controlle and with a flight speed of 30km/h does not obstacle avoidance and flies into the mountain... or.. why the drone does not reverse exactly the flight path while RTH?"

I do not know why RTH does not use obstacle avoidance but to be safe, I usually set the RTH at max altitude (120m) here in UK or 150m in unregulated countries. RTH will use the shortest distance between Home and the aircraft, for the reason to save the battery power.

It is pretty risky to use a drone without a LOS. If I have to use it near mountain/ I will try to launch it from a high place to avoid obstruction of LOS. Also, if RTH is initiated, it will climb 120m higher than Home point. But why cannot you use the DJI Care Refresh?
2017-5-23
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Drone Amateur
New

Germany
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Because you cannot repair something thats not there.
2017-5-23
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Bent Kangaroo
Second Officer
Flight distance : 362510 ft
Australia
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Lok Mavic Posted at 2017-5-23 23:50
But why cannot you use the DJI Care Refresh?

You need a dead body for forensics to replace your drone with Care Refresh system.
No Mavic, no replacement, simple.

Flying in sport mode does disable avoidance system. I thought everyone knew that.
Take that risk especially non LOS and the OP will tell why it is not good idea.
2017-5-24
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Nees
First Officer
Flight distance : 80991 ft
Belgium
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There is an option to activate obstacle avoidance when RTH is initiated, not sure if you activated it or not. I think it is off by default for RTH.

You should also have set RTH much higher , just te be sure. Also, RTH is ALWAYS in a straight path. It will not fly the path you flew. For example, what if you were doing 10 circles around you, why would RTH do 10 circles again before landing? The shortest path is the best.

Sadly, it is user error for not setting height already high enough. But I understand you are now kinda mad and would blame DJI. But with your next drone, you will think: why was I stupid for not setting it high enough.
2017-5-24
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Exib
Captain
Flight distance : 153760 ft
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United Kingdom
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Sorry about the loss of your Mavic hard pill to swallow, but DJI have always said to keep the drone in line of sight, as you stated in your post you were in sports mode the other side of a mountain

No point moaning about it you will just have to take this as a hard lesson learned, to make this even worse if you had read the manual before flying you would know that when in sports mode you have just disabled  obstacle avoidance  
2017-5-24
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Nees
First Officer
Flight distance : 80991 ft
Belgium
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What I do find odd, is that you have no interruption on your map about the location if the drone, if you lost connetion to the drone that triggered the RTH, then I would suspect a gap till connection is established again. Am I wrong?
2017-5-24
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UCBarkeeper
lvl.4
Flight distance : 616982 ft
Switzerland
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maybe a case of wind vs. rth.
if you had still 68% battery after 4300m in sport mode sounds like some tailwind.
very risky flight if you ask me, quite obvious that you could lose the connection / the aircraft.
2017-5-24
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Drone Amateur
New

Germany
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Nees Posted at 2017-5-24 00:13
What I do find odd, is that you have no interruption on your map about the location if the drone, if you lost connetion to the drone that triggered the RTH, then I would suspect a gap till connection is established again. Am I wrong?

I think the missing data gets filled in with data from the drone when the connection is established again, therefore there are no gaps to see in the map?
2017-5-24
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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Drone Amateur Posted at 2017-5-24 00:20
I think the missing data gets filled in with data from the drone when the connection is established again, therefore there are no gaps to see in the map?

Yes, I got connection again for one or two seconds. Thats the reason why we see the first part of RTH flight on the map. but then the connection was lost forever..
2017-5-24
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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Nees Posted at 2017-5-24 00:05
There is an option to activate obstacle avoidance when RTH is initiated, not sure if you activated it or not. I think it is off by default for RTH.

You should also have set RTH much higher , just te be sure. Also, RTH is ALWAYS in a straight path. It will not fly the path you flew. For example, what if you were doing 10 circles around you, why would RTH do 10 circles again before landing? The shortest path is the best.

Even if I set RTH height to 500m... in my case this would not help
2017-5-24
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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Exib Posted at 2017-5-24 00:07
Sorry about the loss of your Mavic hard pill to swallow, but DJI have always said to keep the drone in line of sight, as you stated in your post you were in sports mode the other side of a mountain

No point moaning about it you will just have to take this as a hard lesson learned, to make this even worse if you had read the manual before flying you would know that when in sports mode you have just disabled  obstacle avoidance

I agree with you. It is a hard lesson indeed. I knew that OA is disabled in sport mode. When I lost connection it was too late to change that.

But I think OA could be activated automatically on RTH even if sport mode is enabled and disable it when RTH is interrupted in sport mode.. this should be possible because the mavic flies not at full speed on RTH where OA should work.
2017-5-24
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UCBarkeeper
lvl.4
Flight distance : 616982 ft
Switzerland
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OA should have been on and probably was on. there are a lot of possibilities, why the mavic didn't return in the end.
but the lesson you should learn from this: always be prepared to lose your connection. so make sure that the behavior/settings of your drone if the connection is lost match the surroundings.
so if you have RTH on, make sure the altitude is set correctly. in your case, make sure you don't fly behind anything that is higher then the RTH altitude. Never ever trust the OA to bring back your drone. and read the manual and learn how the drone behaves in situations like that. and again, don't put mountains in between you and your mavic that are higher than your RTH altitude, because that is basically suicide for your mavic. Even if all sensors did good, i guess your battery would be dead if it had to climb over the mountain with OA.
2017-5-24
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DJI-Thor
Administrator
Flight distance : 13602 ft
Online

We are so sorry for the loss of your Mavic. Could you please sync your flight records then send an e-mail with your DJI account email and the date this occurred to support.nl@dji.com, we’ll look into it and create a case for you.
2017-5-24
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Nees
First Officer
Flight distance : 80991 ft
Belgium
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whisperlight Posted at 2017-5-24 00:30
Even if I set RTH height to 500m... in my case this would not help

Why wouldn't it help. It is 500m relative to where you took off. Not 500m sealevel.
2017-5-24
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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Nees Posted at 2017-5-24 01:48
Why wouldn't it help. It is 500m relative to where you took off. Not 500m sealevel.

Yes you are right. Sorry, this was a complete wrong statement from me. RTH height was set to 50m, drone flight height was 103m. I have reconstructed the flight in google earth and with in my opinion a higher RTH height would have helped. And that is the reason I think my mavic could have reached the takeoff point with OA enabled.

I took off on 1622m (sealevel) and the drone crashed at approximately 1725.
2017-5-24
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whisperlight
lvl.1
Flight distance : 201033 ft
Switzerland
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DJI-Thor Posted at 2017-5-24 01:06
We are so sorry for the loss of your Mavic. Could you please sync your flight records then send an e-mail with your DJI account email and the date this occurred to , we’ll look into it and create a case for you.

Thank you. I've sent you an email.
2017-5-24
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rydfree41
Second Officer
Flight distance : 153268 ft
United States
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Sport mode switches off OA .
If you have switched off OA you can set OA independently to be on if RTH is activated , but this is for flying regular mode only .
If you are in Sport mode and activate RTH it stays in Sport with OA off . ( Unless they changed this )

A RTH path will and should not backtrack the initial flight path since using RTH is to find the shortest route back to home due to high wind , battery level etc .
2017-5-24
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Griffith
First Officer
Flight distance : 98537 ft
United States
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Nees Posted at 2017-5-24 00:13
What I do find odd, is that you have no interruption on your map about the location if the drone, if you lost connetion to the drone that triggered the RTH, then I would suspect a gap till connection is established again. Am I wrong?

That may mean only that the RC was still receiving data from the AC, but the signal from the RC to AC was interrupted.  A possibility.
It would be nice to see the log from DJI GO.  Can you upload it to PhantomHelp.com?
2017-5-24
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Bond006
lvl.1
Flight distance : 9908 ft
United States
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you should had engaged in some research to determine the highest height of those mountains then adjust your RTH to  several metres above that height, then the RTH would had worked and not smash into the mountains.  Obstable avoidance + RTH does work BUT to the RTH you specified, if it is lower than the tallest structure in your area, your air craft will crash
2017-5-24
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fans116f1d82
lvl.1
Flight distance : 4094 ft
United States
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I need help i buy my mavic pro today y lose in rive what I can do please dji care
2017-7-14
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fans116f1d82
lvl.1
Flight distance : 4094 ft
United States
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DJI-Thor Posted at 2017-5-24 01:06
We are so sorry for the loss of your Mavic. Could you please sync your flight records then send an e-mail with your DJI account email and the date this occurred to , we’ll look into it and create a case for you.

I need you help
2017-7-14
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alex_markov
Captain
Flight distance : 38850850 ft
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Bulgaria
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I just checked mine and in advanced option OA on during RTH is by default switched ON, so more likely dron run out of juice than hit the slope . But this is good example what needs to be avoided during flights - putting obstacles in between i even hesitate to pass under highway bridge  when start above it as if Mavic loose connection and RTH kicks in  it will crash in to the bridge gaining height.
2017-7-14
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Bekaru Tree
Captain
Flight distance : 15513100 ft
South Africa
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hey whisperlight - that is a sad and unfortunately situation - so sorry for your loss, really. one of the risks, especially as a new flyer, is that many situations can occur that you do not think to anticipate before hand. I almost lost my drone in a similar situation. Fortunately my rth alt was set at 120 and the hill it had to climb over was about 110 m. The trees ontop the hill were 20-30m hight so i was very worried and shaking until i was sure it had cleared the hill and trees. I survived this day but only just and learned 3 lessons.
2017-7-14
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Bekaru Tree
Captain
Flight distance : 15513100 ft
South Africa
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first lesson i learned is to not fly behind a hill - this i did by mistake (in sport mode). the second lesson is to ensure safe rth alt (for where i am flying) - even if that means breaking the height limit by a bit and 3 - beginners need a fair amount of luck to survive and live to become more experianced pilots. would b great if they could do some type of gps ping ability with a small second battery that activates when primary battery goes dead or when a crash is detected.
2017-7-14
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Bekaru Tree
Captain
Flight distance : 15513100 ft
South Africa
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Maybe you can reach out to other drone pilots to help you find your drone based on your map locations - i live in africa so it is too far for me but if a local drone flyer reached out to me and was within reasonable trave distance i would definately give it a try to help them try to find their drone - i am always looking for reasons to fly and searching for a drone seems like a fun day out - good luck, do not give up - anything is possible - all you must do is to find it and yr chances will increase the more u try - with something to give back to dji u will be back flying again.
2017-7-14
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SRO
Second Officer
Flight distance : 2405174 ft
Switzerland
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UCBarkeeper Posted at 2017-5-24 00:18
maybe a case of wind vs. rth.
if you had still 68% battery after 4300m in sport mode sounds like some tailwind.
very risky flight if you ask me, quite obvious that you could lose the connection / the aircraft.

Yes, a very strong tailwind. I find it hard to believe: 4300m with only 32% energie loss, in sport-mode. The air is thin in the mountains. The mavic needs more energy. Finally the sport-mode was the mistake and never fly behind a Swiss mountain.
2017-7-14
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Bekaru Tree
Captain
Flight distance : 15513100 ft
South Africa
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One hour after i posted to you this morning i went flying and lost my drone - although i was lucky to find it again.
Have you gone to your FIND MY DRONE feature - How to?
Open the app - on the first screen before you enter your device (drone) - at the top of this page are 3 horizontal lines - click on this menu bars and options will open - in these options is FIND MY DRONE
Click on this - a map will open showing the location of yr drone - if u click onto the red aircraft image a new screen will open showing GPS co ordinates

I hope this gets you a step closer to your drone
2017-7-15
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