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Accident analysis - lost Mini 3 Pro
921 11 2024-2-23
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iwanou
lvl.2
Flight distance : 782549 ft
Poland
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I would like to ask for an analysis of the accident and your opinion on this rth,sensors and whole situation

A few days ago, while flying near the lake, my drone had an accident while landing. During RTH, I looked at my friend's screen for a moment because we were flying two drones. it was literally 10 seconds and I heard my drone hit a tree and fall into the water. It was above our heads and in the place where I started. It was so unlucky that the drone landed in a place where there is no ground, right behind the reeds. I couldn't do it without the equipment and I passed winter swimming. Perhaps a fellow diver will catch it and that's why I'm waiting to report it to the DJ. Unfortunately, I do not have DJI Care protection, the drone itself has not yet been paid off, so my annual hobby is at great risk. I realize that I made a few mistakes because I could have landed more safely on my own without RTH and a moment of inattention.

Air Data
https://app.airdata.com/flight/fe2bfce9f2e185469a1cbdfa2f2308b0/GENERAL

Phantomhelp

https://www.phantomhelp.com/logviewer/13DA3IFN100R27ZDNXO5/
It seems to me that the homepoint was updated incorrectly, I drew on the map where I think it should be located. I started from this place, which does not change the fact that the sensors from below did not work properly.

Thank you












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2024-2-23
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Sean-bumble-bee
Core User of DJI
Flight distance : 15997 ft
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United Kingdom
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Sorry about the drone but it does look as if you launched quite close to the tree line.
That's not the best place to take off when the RTH height is 230ft and there is likely to be a vertical descent involved in an RTH landing.
That said, many of my flights have been launched from such places but I never take my eyes off the drone during the landing phase, in fact, in such places I rarely let the drone autoland.

The drone's VPS sensors seem to have started to detect the tree at 12:51.1 and seems to have started to reduce the descent rate but as far as I know the drone is not programmed to stop a landing unless is rejects the landing site and I doubt bare tree branches offer a big enough target for the sensors to consider the site unsafe.
I do not know what criteria the drone uses to determine what is safe and what is unsafe.

Unfortunately I think this goes down as pilot error ....... for taking your eyes off the drone during the landing phase.

How deep is the water?
If the drone leterally landed just beyond the reeds is it not wadeable?
Don't try it on your own, go with your friend and a rope long enough to reach the crash site and pull you out just incase there is a drop off.
It might not be pleasant but a change of clothes and a towel would probably overcome that.

How many mini 3 pro do you have? Your 'panel' appears to show two.

I am curious about why the drone switched to P-GPS ( Bypass ) during the descent.


height, vps height, Z speed.png
2024-2-23
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iwanou
lvl.2
Flight distance : 782549 ft
Poland
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Sean-bumble-bee Posted at 2-23 07:44
Sorry about the drone but it does look as if you launched quite close to the tree line.
That's not the best place to take off when the RTH height is 230ft and there is likely to be a vertical descent involved in an RTH landing.
That said, many of my flights have been launched from such places but I never take my eyes off the drone during the landing phase, in fact, in such places I rarely let the drone autoland.

You're right, I realize it was my costly mistake. Unfortunately, the depth is about 2 meters, I was wondering if a neodymium magnet would be able to attract it because it would be difficult to dive there on my own.
Although a familiar diver will probably do it, but only in a few days..

Unfortunately, this is my only drone, the previous one was only added for testing.
2024-2-23
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Sean-bumble-bee
Core User of DJI
Flight distance : 15997 ft
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United Kingdom
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iwanou Posted at 2-23 07:56
You're right, I realize it was my costly mistake. Unfortunately, the depth is about 2 meters, I was wondering if a neodymium magnet would be able to attract it because it would be difficult to dive there on my own.
Although a familiar diver will probably do it, but only in a few days..

"Unfortunately, the depth is about 2 meters, " ah ...... bad luck.
2024-2-23
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JJB*
Core User of DJI
Flight distance : 13925262 ft
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Netherlands
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Hi,

Had a look at your flightlog too.
Same conclusion as Sean.

See my chart of your data.

Descend speed is automatically reduced from 5 m/s to almost zero at 0.5 meter in a RTH landing or normal landing.
Speed was already reducing before the combination of down vision and IR height bottom sensor was seeing/measuring any obstacle/height.
So no time for landing protection to stop the landing and mark the area as unsafe.

Just bad luck to be so close to the trees for a RTH.

BTW  same for take-off on any spot near water, if a drone looses connection close to HP but above water (and no reconnection for some reason) it will land in water...
If it detects an unsafe area that it will hover, go for a swim, if it does not detects an unsafe area drone goes for a swim.


cheers
JJB   [ Charts by FRAP ; the 'best' software for data and visual flightlog analysis (www.jjbfrap.eu) ]
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2024-2-23
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Lieutenant
Second Officer
Australia
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Is the water clear enough to see the drone ?
You could buy one of these grabber tools locally and attach it to a long stick.

2024-2-23
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DJI Wanda
Administrator
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Hello there, we're sorry for any inconvenience caused you. May I confirm if your drone is still unable to be salvaged? If so, you can report flyaway via this link: https://repair.dji.com/us/repair/flyaway and our relevant departments will follow up on the case for you. If there is a doubt about the accident, data analysis can also be applied as long as the drone is under warranty. Thank you.
2024-2-23
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DJI Paladin
Administrator
Flight distance : 318 ft

Online

Hi there. Thank you for reaching out and we're deeply sorry for the incident that happened to your unit. If the unit is within the original warranty period, you may contact our team at https://www.dji.com/support to start a flyaway ticket. Kindly please sync your flight records on the app and wait for their instructions. Please don't hesitate to reach us if you have further inquiries.
2024-2-23
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Ian in London
Core User of DJI
Flight distance : 9082933 ft
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United Kingdom
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Ah, really sorry for you!  Flying over water is always so brutally unforgiving; if the props hit anything, down it goes into the water.  
Consider getting a refurbished Mini 3 for €385  (Mini 3 has no obstacle avoidance) and you can pair it with your RC remote if that's what you have.  
The DJI store has a few options for you and they're cheaper than buying brand new, but still come with full warranty.   Best of luck, Ian
https://store.dji.com/pl/product ... m=pages-refurbished
2024-2-24
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iwanou
lvl.2
Flight distance : 782549 ft
Poland
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Ian in London Posted at 2-24 07:41
Ah, really sorry for you!  Flying over water is always so brutally unforgiving; if the props hit anything, down it goes into the water.  
Consider getting a refurbished Mini 3 for €385  (Mini 3 has no obstacle avoidance) and you can pair it with your RC remote if that's what you have.  
The DJI store has a few options for you and they're cheaper than buying brand new, but still come with full warranty.   Best of luck, Ian

I managed to fish out the drone, cleaned it, removed the batteries and put the drone in the rice. It is covered by the original warranty.
I would like to ask you for further steps, where exactly to report the event for analysis

Thank you for all your previous replies.
2024-3-9
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Sean-bumble-bee
Core User of DJI
Flight distance : 15997 ft
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United Kingdom
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iwanou Posted at 3-9 09:25
I managed to fish out the drone, cleaned it, removed the batteries and put the drone in the rice. It is covered by the original warranty.
I would like to ask you for further steps, where exactly to report the event for analysis

Congratulations on recovering the drone.
2024-3-9
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Gabriel Tallon
lvl.4
Flight distance : 2636457 ft
United States
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Good job retrieving it!
2024-5-11
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