Lost DJI mavic mini
577 11 2020-9-8
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djiuser_n7hgJzBxpa1w
lvl.1
Flight distance : 123353 ft
Canada
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Hello Guys,

I lost my Mavic mini in Frontenac Provincial Park in Ontario.
What's surprised me was, the drone was flying at a distance of 200 m and started drifting away. It wasn't responding to forward and backward function. But I had the control of Gimbal and left- right movement. I tried doing everything from 200m it slowly drifted apart till 900m and lost connection. I tried to locate it using 'find my drone' but had to give up searching after few hours. It was a bit windy but I had flown in worst conditions.
I had purchased care refresh but I know it won't help me if I don't have the product. Can someone suggest me what to do. I was getting into aerial photography. But I don't think I can afford a drone again for a while.

Ps:
I have attached the last picture taken by the drone.
Screenshot_20200908-074053__01.jpg
2020-9-8
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Labroides
Core User of DJI
Flight distance : 9991457 ft
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Australia
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Can someone suggest me what to do.
You'll need to post your flight data and someone might be able to analyse it and work out what's happened.

Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report you can post a link for the report here.
Or just post the .txt file.
2020-9-8
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djiuser_n7hgJzBxpa1w
lvl.1
Flight distance : 123353 ft
Canada
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Hey thanks for the response

https://www.phantomhelp.com/LogViewer/IOD9FHLVDZ6ZE75MZWUE

Here's the flight log
2020-9-8
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Labroides
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djiuser_n7hgJzBxpa1w Posted at 9-8 04:26
Hey thanks for the response

https://www.phantomhelp.com/LogViewer/IOD9FHLVDZ6ZE75MZWUE

There's evidence of the wind in your data.
At 5:45 the drone was 81 metres up and trying to hover but it was leaning 20 degrees to one side being set off at 1.9 metres/sec.
At around 6:30 you turned the drone toward home aand shortly after, sent it up to 108 metres, where it was being blown backwards at up to 3 m/s while hovering and also pitching forward at up to 30 degrees which indicates it was flying at full speed just trying to hold position.
At 7:25 (93 metres up) you started trying to fly back but the Mini was losing ground at up to 4 m/s in gusts and just managing to hold position when the wind eased.
You tried SPort Mode later but still couldn't make headway and at 9:37.3, gave up and went to RTH.
You tried SPort and RTH a few more times but the drone kept going backwards.
Signal was lost at 12:30.3 with the drone 800 metres away and still going backwards at 4 metres/sec and 68 metres up.
Autolanding was initiated just before signal was lost.

I'll do some calculating to get a rough idea of how much further it might have blown before finding the ground and some comments.
2020-9-8
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djiuser_n7hgJzBxpa1w
lvl.1
Flight distance : 123353 ft
Canada
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Thank you so much for the insight. I was trying to understand the flight data, I'm quite new at this.
2020-9-8
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Labroides
Core User of DJI
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What's surprised me was, the drone was flying at a distance of 200 m and started drifting away. It wasn't responding to forward and backward function. But I had the control of Gimbal and left- right movement.
The data shows that you had full control but the wind at that height was too strong for the drone to make headway against the wind.
It was like rowing upstream at 4 metres/sec but having a current flowing at 6 m/s.
The result is that the boat goes downstream with you getting tired rowing as fast as you can, and your drone kept being blown backwards while flying forwards at full speed.

I tried doing everything from 200m it slowly drifted apart till 900m and lost connection.
There were a few things you could/should have tried (but didn't).
The first was to be aware of the wind direction and speed and avoid flying off downwind which meant you were going to have a fight to come home against a stiff headwind.
The second was that you weren't monitoring your speed to see how the wind was affecting the drone.
The third was that you weren't aware that up higher, the wind is stronger.
Leaving the drone up that high was the fatal mistake.
If you had brought it down to 20-25 metres early on, you could have brought it back easily.

It was a bit windy but I had flown in worse conditions.

I suspect that assessment isn't accurate.

At loss of signal it was 68 metres higher than the launch point and 800 metres north and still being blown backwards at 2-5 m/s (but this will have reduced as the drone came lower).
At signal loss, the drone was 51 metres above the ground, but only 220 metres from a deep lake with a 30 metre high bank.
Autodescent will have taken the drone down at 1.8 m/s.
Descent of 51 metres would have taken 28 seconds, in which time the drone might have blown a further 56-84 metres (rough estimate).
I'd guess that the drone probably found the ground before it reached the lake.

Signal was lost at 44.53729  -76.52104.
If you wanted to search I'd walk to that point and continue for another 50 metres and start searching in the dotter line area on the illustration.



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2020-9-8
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djiuser_n7hgJzBxpa1w
lvl.1
Flight distance : 123353 ft
Canada
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Hello, Thank you for the detailed comment. So, I should have been careful with the wind I guess.
2020-9-8
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djiuser_n7hgJzBxpa1w
lvl.1
Flight distance : 123353 ft
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I'll see if I'm able go back again and search in the marked area. Thank you so much for your quick analysis and response.
2020-9-8
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fans00087ec3
lvl.2
Flight distance : 118402 ft
United States
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djiuser_n7hgJzBxpa1w Posted at 9-8 06:19
I'll see if I'm able go back again and search in the marked area. Thank you so much for your quick analysis and response.

I really hope you find it, please let us know if you find it.
2020-9-8
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mark117h
Second Officer
Flight distance : 241306 ft
United Kingdom
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djiuser_n7hgJzBxpa1w Posted at 9-8 06:19
I'll see if I'm able go back again and search in the marked area. Thank you so much for your quick analysis and response.

Hi djiuser_n7hgJzBxpa1w
As others have said, i really do hope you have luck in finding your drone, some of the guys on this very forum are really good at interpreting the data and being able to give a rough estimate of where the drone could have possibly come down / landed.

What i would also like to add is that if you are able to make it out to go find the drone, have a good look around the area but also pay attention to the tree tops/canopy's as it could be wedged/stuck up a tree.

Anyways mate hope you have luck finding your Mavic Mini.
2020-9-8
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JJB*
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djiuser_n7hgJzBxpa1w Posted at 9-8 06:19
I'll see if I'm able go back again and search in the marked area. Thank you so much for your quick analysis and response.

Hiya,

Had a look at your flight too.

You know already what happend, but do you know that at 4m16seconds your HomePoint was updated, that time flying 662 feet away from your starting point?
So with less wind and a disconnect your MM would fly to that point and not to the starting point of your flight. (or did you moved yourself to another point and updated HP?)
New HP = yellow diamond marker.
In your DAT file for this flight wind data is stored, if you like post a link to that file on here.
DAT file on the mobile device (MCDATflightrecord map), filename = FLY055.DAT.

Did you noticed the compass error at start?  error =  "Compass error. Ensure there are no metal or magnetic objects near the aircraft and calibrate it before use"
(nothing to do in this flight with loosing the mm, just for your info)
When i check the pitch down angles for your drone in sport mode, not more than 14 degrees down, normally with 100% forward stick in sport mode should be about 25-28.
I am not sure about too much wind for your MM, at some points in your flight it held (almost) position. see the chart #3 ;   sport mode 15 degrees down and 1.3 ms back drift, so with fully forward it should win from the wind there. Max tilt is 30 degrees in sport mode, see MM specs.

So curious about the DAT, and i would ask DJI for help, imo its a MM wich did not deliver all the power (wich it should deliver) in this flight.

BTW as proof see the last chart, my onw MM against the wind.  Wind speed 14 m/s, in N mode craft pitched down to 26 degrees and holding position.
So if your MM only reached 15 degrees down....

cheers
JJB






analysis1.png
analysis2.png
analysis3.png
MyMaxWindTest1.png
2020-9-8
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DJI Stephen
DJI team
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Hello there. I am sorry to read and to know what happened to your DJI Mavic Mimi. Since this unfortunate incident happened and you have lost the said 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 for your understanding.
2020-9-8
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