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Mini fly away (& recovery)
928 18 2022-12-16
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tioee
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Ireland
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I had a loss of control of my mini 3 pro last weekend.Flying over a whitewater river it was parked about 5-10m above the river at a rapid and all of a sudded it took off downriver at speed.
Straight away I guessed it was tracking the foam/or wave pattern in the water, I increased the altitude & I got control back and was able to land it without any more incidents.
I've since had in out twice (over land) and its behaving normal.
I am now sure that the downward vision sensors may have been confused & tracked the pattern of water and moved with it.
I have read the Dji support page, "how to fly safely over water" there is an instruction given on how to turn off the downward vision sensors to avoid this situation.
https://store.dji.com/guides/how-to-fly-safely-over-water/
I'm using the Dji RC with a screen, the above guide is obviously old going by the graphics, but in the current version of the "fly app" on my controller I can't find any way to turn these sensors off.
Is that it, the ability to fly safely over water has been made more dangerous?





2022-12-16
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Sean-bumble-bee
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I think the App shown in your link is Go4, the fly app is much dumbed down in comparison to Go4.
As far as I know there is no way to switch the bottom sensors off in the Fly App. You can mask them with tape BUT BE WARNED, if you do that you will probably lose "landing protection", if so it is probable that you would be able to manual command the drone to descend at full speed into the ground. At a guess automated landings would not be much better.
It's like stepping from a Mavic to a Phantom 3


However, if you had a full compliment of GPS satellites during this incident could you PLEASE post the flight log for this flight? There are instructions for retrieving the logs on the following page
https://mavicpilots.com/threads/ ... -controller.127069/

2022-12-16
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tioee
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Ireland
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Sean-bumble-bee Posted at 12-16 12:12
I think the App shown in your link is Go4, the fly app is much dumbed down in comparison to Go4.
As far as I know there is no way to switch the bottom sensors off in the Fly App. You can mask them with tape BUT BE WARNED, if you do that you will probably lose "landing protection", if so it is probable that you would be able to manual command the drone to descend at full speed into the ground. At a guess automated landings would not be much better.
It's like stepping from a Mavic to a Phantom 3

Thanks for the help. I think you are right about it not being a clever idea to tape over the sensors, there seems to be a few bad stories on these forums about the consequences of doing that.

To get the logs off the software on the rc (with the screen for the mini 3 pro) was a bit different than in that link, I found this and it worked https://mavicpilots.com/threads/ ... 27069/#post-1438281

I'll post the logs below, thanks again.
2022-12-16
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tioee
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Ireland
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https://www.phantomhelp.com/logviewer/274X693X5RO25YNOQOCG/
2022-12-16
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tioee
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Ireland
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Looking at those logs I can see that it happened at about 6.40 sec, there seemed to be good sat coverage, however the VPS seems to have intermittent throughout. You can see the path it took following the the waves / foam on that channel of water. Thats a photo of what it looked like.
2022-12-16
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Bigplumbs
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Flying any drone too low over water is not a good idea. Just fly higher and use the Zoom function
2022-12-16
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Sean-bumble-bee
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Thanks for the log.
I am a bit puzzled, where did the drone land?
Did you lose connection at any point?
The log ends with the drone at a height, according to the barometer, of 9.2ft relative to the home point, but 3ft above something ( a bush or tree hanging over the river perhaps) according to VPS,  and 321ft away from the home point.
Just curious, I don't think it is important but is there another flight log after this one?
2022-12-16
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tioee
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Thanks for looking in it in enough detail to spot that!

I better explain it so it makes sense, I put the drone Ito the air from the deck of an open canoe from the home point, I flew it down to the small rapid took a few shots and then put the it up above the tree tops in a hover so I could leave it there while I paddled down. I put the controller into a dry bag in my boat paddled down passing under the drone (this might explain the distance to the controller changing when the drone is logged as being stationary). I would have passed under it and past it and then pulled in to the side of the river where the track ends. I flew it about a little more there and then as soon as it shot downstream by itself I kept at high above the level where this behaviour happened and flew it back to me where I was kneeling in a canoe. I was pulled-in, kind of in between two trees and I hand caught it flipping it upside down at about that 3ft height above the water which might explain the 3ft reference.
I don't know what the 9ft could be, unless its -9ft, which would be about the height loss from where I took off upstream to where I was below the drop?
2022-12-16
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tioee
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Bigplumbs Posted at 12-16 14:47
Flying any drone too low over water is not a good idea. Just fly higher and use the Zoom function

Thanks, but I'm well used to doing it just not with Dji drones, I do understand the risks though so thanks.
2022-12-16
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gnirtS
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Mini 3 badly needs an option to disable VPS and OA sensors as previous drones have.
They can get confused, can cause errors and at worst, can cause crashes or a failure to return home.

(The Mini also doesnt have a zoom function.  Its no more than a low quality crop.).
2022-12-16
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tioee
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Thats me in the bigger red boat where I landed (hand caught it).
2022-12-16
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tioee
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Ireland
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Sean-bumble-bee Posted at 12-16 15:03
Thanks for the log.
I am a bit puzzled, where did the drone land?
Did you lose connection at any point?

Oh, I never noticed that it lost connection, I don't think that it did, if it did while I was flying it I would have noticed, it may have without me knowing while the controller was in the bag as I was paddling but almost certainly it didn't when I was flying it.
I also checked the next logs, they are from a different area comply, these logs would seem about right to me, that's where I started from, and where and when I landed it after it scooted away.
2022-12-16
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Sean-bumble-bee
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The barometer height and reported distance are all relative to the home point/ launch point so when you are mobile you need to keep that in mind. Had you RTHed the drone it would have returned to the launch point and maybe gone for a swim.
You can reset the home point but remember it isn't a moving home point, it is a static home point or series of static home points and as far as I remember the height will always be relative to the takeoff point.
Regarding the reported barometer height, I'd guess the drone had a bit of barometer drift then, it's not unheard of but it might be an idea to do a check flight and land at the launch point just to see what the normal drift is. Catching below the rapids but 3ft above the water level could, I suppose, be slightly above deck height above the rapids. But negative heights are reported as negative heights.
2022-12-16
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Sean-bumble-bee
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tioee Posted at 12-16 16:10
Oh, I never noticed that it lost connection, I don't think that it did, if it did while I was flying it I would have noticed, it may have without me knowing while the controller was in the bag as I was paddling but almost certainly it didn't when I was flying it.
I also checked the next logs, they are from a different area comply, these logs would seem about right to me, that's where I started from, and where and when I landed it after it scooted away.

Given what you said in post 13 I no longer think there was a disconnection, the track agrees with your description.
But you should be aware that it seems the mini 3 has a ridiculously small, 3 sec, trigger period for the failsafe action.
https://forum.dji.com/forum.php?mod=viewthread&tid=273298
Your drone has the default action set, go home, so it would have RTH'ed and maybe gone swimming if there had been a disconnection.
You'd best read up on failsafe behaviour for any future expeditions on water.
I was going to say that your RTH height was a bit high but given you are on the water and might not have immediate access to the controller or the take off point, it might be wise to keep the RTH height high (on calm days)  to give you a chance to do something useful if you ever suffer a water borne disconnection.
But I would say you max height is far too high, last time I took note I thought Eire had a 400ft AGL ceiling.
2022-12-16
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JJB*
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Hi,

Lucky you to still have your Mini3pro!

Flying low over streaming water will confuse the bottom sensors.
Result is that drone will follow the stream....this without RC input.
Often followed by GPS mismatch, moving speed increase and often remote pilot looses craft control.

Your link to "how to fly over water ect" is old Go4 video, wich DJI is always posting to users using FlyApp drones. (silly of them ofcourse...)

Bottom sensor cannot be switched off !
For many years users have been asking for disabling the sensors, DJI will not do that.

Leaves only one option for flying over water; do not fly too low and for sure not too low over streaming water.
I fly a lot over water, but doing this only when drone is in sight, so i can react quickly (UP stick) if drone behaves 'out of control'.

see this > https://forum.dji.com/forum.php?mod=viewthread&tid=279616  post 39

cheers
JJB
2022-12-17
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Sean-bumble-bee
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JJB* Posted at 12-17 02:28
Hi,

Lucky you to still have your Mini3pro!

Thanks JJB I was looking for that thread but couldn't find it. It's bookmarked now.
2022-12-17
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tioee
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Sean-bumble-bee Posted at 12-16 16:38
Given what you said in post 13 I no longer think there was a disconnection, the track agrees with your description.
But you should be aware that it seems the mini 3 has a ridiculously small, 3 sec, trigger period for the failsafe action.
https://forum.dji.com/forum.php?mod=viewthread&tid=273298

Thanks for that, I've not fully read the manual yet, I was aware that the RTH points were static (from seeing the homepoint updated message flash up on the screen. Here where I had the drone in very close range and safe above the trees & a RTH height of 100m I thought it was safe enough...I assumed that while it would RTH that it would RTH and descend but not attempt to land until confirmed to do so, or when it would get a critical low battery giving me plenty of time only a minute or two between bagging the controller and getting it back out, however I'm guessing if it would land or not after the RTH, something I need to clarify soon.
I do indeed have the AGL ceiling set way above the Irish IAA's limit, however I sometimes fly in places where having a lower limit set wouldn't be appropriate, eg flying along side large cliffs where 20-50m horizontally to my right the ground level is still high above me, I would also occasionally fly offshore beyond the 12 mile limit where the limit is not applicable.
In any case it seems that there is no way to disable the bottom sensors so there is no real safe way to fly over moving water in conditions like I was in. Thanks again I'll read the on RTH system a bit more. (I've been used to the Yuneec system over the last few years, it constantly updates the home point tracking the controller and will RTH to about 8-10m of the last known position of the controller)
2022-12-17
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tioee
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JJB* Posted at 12-17 02:28
Hi,

Lucky you to still have your Mini3pro!

Thanks, that's it, I'm just glad now that I didn't have it below the trees at the same time that it misread the river and there was empty air for it to move into. Until someone build a periscope to add to the sensors to read the empty or another way to trick them I'll be very slow to bring this drone on the river again. Its only the moving water that I will want to film so I may look at getting another brand for that (my old Yuneec machines worked just fine for this)
2022-12-17
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Sean-bumble-bee
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Although the drone may reject a landing site it would be unwise to assume that it will, especially when the landing site is water, it only needs to NOT REJECT the landing site over water once to cost you the drone. At least one drone flier here or on mavicpilots has lost their drone because they had changed the failsafe setting to "land" and the drone disconnected over the sea and did 'land'.
Be aware that calm windless conditions down low do not necessarily mean windless conditions up high, indeed wind speed tends to increase with height. That said I think for water borne adventures on seemingly windless days a high RTH give you a safety margin time wise.
With regards to max ceiling, it takes only seconds to set it to something appropriate at the start of a flight, I reset the RTH height for every 'new' location and, if I could get those accursed sliders to set the value I wanted, it would take no longer than setting the max height ceiling.
It's your neck but I strongly suggest you set the max height to within IAA legal limits. The only time I have set max height higher than 400ft was when I wanted the drone to climb a hill.
One word of warning though, if you reset a limit slider, check that you have not accidentally changed another one. One of those up a hill flight cost me an RTH to well over 800ft, it might have in excess of 900ft, after coming down the hill I had flown over the sea and lost connection, I must have accidentally dragged the RTH ceiling slider when setting the max ceiing. If there had been wind up there the drone would have been lost. Incidentally RTH height can not be set higher than max height and reducing max height to below RTH height will reduce the set RTH height.
2022-12-17
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