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crash in Antarctica Mavic mini
700 22 2-15 03:07
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charlesantarcti
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hi guys, i would need some of your help about few crash..
i'm in the middle of Antarctica with some extrem weather conditions, for the moment it's still summer and we do get -60 quite often.
our base are high in altitude 3220m but it's an equivalent of 4000m high due to low pressure.
we got 3 Mavic mini, and all of them crash after few minutes or few second of flight.
the issue is, we are losing the gas control and the drone keep climbing...
the first flight i did manage to land the drone after 6min of struggle trying to get control of it, it did climb to 150m on it's own.
second flight, same issue but the engine did stop working at 100m high then crash...
third flight was the worth... outside was -60, did take off and after just 30sec i loss control, then the drone start to climb itself until my last signal with the remote the drone did climb to 600m, then crash.... lucky the snow were fresh so not much damage.
any of you got a clue of what happening? i still got control of everything else, but can't get the drone back down.
my next solution is to attach some fishing rope to the drone to be able to bring it back home

thanks


2-15 03:07
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JJB*
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Hi Charles,

Wow, 3 mini`s crashed.

Best to get help is to upload the flightlogs, using > https://www.phantomhelp.com/LogViewer/Upload/
Or just put a cloud-link to the flightlogs on here.

-60 = Minus 60 centigrade ??  (well out of specs fro the mini to operate)

cheers
JJB
2-15 03:48
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Labroides
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we got 3 Mavic mini, and all of them crash after few minutes or few second of flight.
First up .. the Mini is the slowest, most underpowered drone DJI made.
It's the worst choice to fly in a windy location.

But it seems your problems (so far) are different.
Two items from the Operating Specs are significant:

Operating Temperature Range:      0° to 40°C (32° to 104°F)
Maximum Takeoff Altitude:  3000 m

The fall-from-the-sky issue is likely to be the battery being unable to deliver the required voltage due to the temperature.
The recorded flight data would confirm whether that is the case.

The uncontrolled climbing might be due to a problem with the downward facing sensors.
Again, the data would be required to tell.
2-15 04:43
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m80116
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I think you're main problem is operating the drone in a too thin air than it is designed for. Probably the FC is acting up on values that it doesn't deem reliable.
2-15 13:10
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Geebax
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m80116 Posted at 2-15 13:10
I think you're main problem is operating the drone in a too thin air than it is designed for. Probably the FC is acting up on values that it doesn't deem reliable.

It would not have anything to do with thin air, the flight controller has no way of determining density altitude. The mini is a poor choice for operating in the chosen environment. I would be interested in knowing how many GPS satellites the aircraft can see. The most likely cause is poor battery performance in those temperatures. Minus 60 is way outside the specs and pretty brutal.
2-15 14:11
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The Saint
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wow, major trip to Antarctica (with some of the worse weather conditions on the planet), prob once in a lifetime event, and all you can manage to bring is a handful of mavic minis?  they don't even work well on a relative calm summer day in the rural countryside in the middle of america where i live what makes you think it's going to work down there?  /s /s /s /s
2-15 14:30
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m80116
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Geebax Posted at 2-15 14:11
It would not have anything to do with thin air, the flight controller has no way of determining density altitude. The mini is a poor choice for operating in the chosen environment. I would be interested in knowing how many GPS satellites the aircraft can see. The most likely cause is poor battery performance in those temperatures. Minus 60 is way outside the specs and pretty brutal.

It has a way that's called called the pressure sensor. It is a very good and clear indirect indication of air density as pressure and air density drops with height on this planet and around it.

Come back in 900 milion years and things might have changed.
2-15 15:23
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Labroides
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m80116 Posted at 2-15 15:23
It has a way that's called called the pressure sensor. It is a very good and clear indirect indication of air density as pressure and air density drops with height on this planet and around it.

Come back in 900 milion years and things might have changed.

Come back in 900 milion years and things might have changed.
Do you think that you might understand the problems of lithium batteries pumping electrons at -60° by then?

As the Minis managed to climb, your suggestion isn't the cause of the issue.
The problem was not being able to stay up there.


2-15 18:16
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DJI Stephen
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Hello there charlesantarcti. I am sorry to read and to know what happened to your DJI Mavic Mini and thank you for reaching out. Since there was a crash that happened before. It would be best to contact our DJI support team at https://www.dji.com/support for further assistance. We have a team that will do there best to assess the said drone and give out the best resolution for this issue. Again, I am sorry for this trouble and thank you for your understanding.
2-15 19:11
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The Saint
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sounds like  all drones are banned down there unless perhaps you have special permission or government access, research, etc.  so i guess you fly what you have; understandable, maybe a sub-250 can somehow fly under the radar.

i really dislike the thought of these total bans in certain areas, at least they can allow restricted or severely limited access; maybe even with monitoring. when you completely ban something, you can be sure the ban will be ignored by the criminals and you end up with a worse situation then if you tried to control everything.  i checked, several nice yt videos from down there.
2-16 11:30
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Zbip57
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Page 36 of the Mini User Manual says this about operating in Polar Regions:

Polar Regions

Polar Regions


That just means GPS reception might be weak within the polar regions, but that really shouldn't affect controllability.  Worst case, if it has no GPS lock and is operated higher than the Vision System's range of ~10m height, the Mini just won't be able to hold position in a hover when the sticks are centred.  It would drift with the wind, but you should still be able to otherwise drive it around controllably in ATTI mode.

I'd be more worried about compass errors when operating that close to the magnetic pole.

But that still doesn't explain why it would climb uncontrollably.  I think Labroides is on the right track suspecting an issue with the downward facing sensors.  The Mini has a single downward facing camera lens used to detect surface features which it then uses to hold horizontal postion whenever sticks are centred.  It also has two infrared sensors that measure the Mini's height above ground.

The height sensors will detect if the Mini is too close to the ground (~0.5m) and will automatically increase the height of the Mini.  You can test this by placing your hand under the Mini as it is hovering.

If those sensors are obstructed with snow or frost, perhaps that is what is causing the Mini to uncontrollably keep increasing its height?

2-16 18:25
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Geebax
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The Saint Posted at 2-16 11:30
sounds like  all drones are banned down there unless perhaps you have special permission or government access, research, etc.  so i guess you fly what you have; understandable, maybe a sub-250 can somehow fly under the radar.

i really dislike the thought of these total bans in certain areas, at least they can allow restricted or severely limited access; maybe even with monitoring. when you completely ban something, you can be sure the ban will be ignored by the criminals and you end up with a worse situation then if you tried to control everything.  i checked, several nice yt videos from down there.

Where do you get the idea that drones are banned in Antarctica? Seven different countries have territories in Antarctica, so they would all have to agree on a ban.
2-16 18:40
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Cetacean
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Aloha charles,

     Zbip might be on to something as well as confirming what Geebax, Labroides and some others mentioned.  The vision sensor may have a problem because of very low contrast due to all the snow.  The climbing for more altitude might be to find more objects to use for contrast in combination with GPS issues in the polar regions.  It would be better to fly over bare rocks so the vision sensor can use the rocks for contrast.  Your worst conditions for flying is the fresh snow you noted.  The best conditions for a soft crash landing is the same fresh snow.  No wonder you are having problems!

     As for the cold and base altitude, you are flying way outside the specs as noted.  To help with the cold, you can try to fly under the warmest conditions available and prewarm the batteries.  The drones DJI sells for cold weather flying include preheating battery products and recommendations to preheat batteries for flight.  I have no idea how that might work with those very small Mavic Mini batteries under those very cold conditions.  But when the Mavic Mini starts flying it does generate heat and I get a lot of overheating warnings - but the Mini and its batteries have to start out well heated in your conditions.

     Try to do some experiments like spacing some of your equipment around a larger footprint and take off in the middle.  Try to stay low like at the original hover used in the auto-takeoff option.  Then very slowly increase altitude to 10 meters and land again if possible.  If the Mavic Mini starts climbing out of control, fly over to a patch of soft fresh snowfall and do the CSC maneuver (manually turning off the motors).  Hopefully, the soft snow will soften the crash as you noted before.

     Be sure to enable the CSC option in the Control Settings (three vertical dots in the upper right corner of the display).  We normally do not enable this option, but in your case, it might be helpful.

     Look at the camera lens and the sensor lenses to see if they have a clear view.  If the cold is causing some sort of occlusion, you might be having even more issues than anticipated.

     I hope this helps!  Take care and be safe!

Aloha and Drone On!
2-17 02:22
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The Saint
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Geebax Posted at 2-16 18:40
Where do you get the idea that drones are banned in Antarctica? Seven different countries have territories in Antarctica, so they would all have to agree on a ban.

just a simple google finding articles like this:  https://www.maritime-executive.c ... itors-in-antarctica

i'm sure it is more complicated than i'll ever understand but it appears to be a recent issue and likely there is some sort of group or consortium to handle the different governments down there to keep things consistent. plus i had heard you can't get down there on your own so whoever you contract with might count for something as well.  obviously there are exceptions....
2-17 06:59
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Geebax
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The Saint Posted at 2-17 06:59
just a simple google finding articles like this:  https://www.maritime-executive.com/article/iaato-restricts-commercial-drone-use-by-visitors-in-antarctica

i'm sure it is more complicated than i'll ever understand but it appears to be a recent issue and likely there is some sort of group or consortium to handle the different governments down there to keep things consistent. plus i had heard you can't get down there on your own so whoever you contract with might count for something as well.  obviously there are exceptions....

That is a tourism operation group, they would not have any ability to enforce a ban of any sort.
2-17 13:08
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The Saint
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Geebax Posted at 2-17 13:08
That is a tourism operation group, they would not have any ability to enforce a ban of any sort.

i saw that.  sure if you can find a way to get down there without going thru them, you can probably fly your drone, pet the penguins, bring back rocks....

all i know is if you are under the organization umbrella, you'll prob have to follow their rules.  not sure how they enforce things outside of contractual details but perhaps the o.p. can elaborate.  clearly this isn't restricted airspace or tfr's there but it appears the groups have come together to control all the tourists regarding drones.  unless you can take your own boat or plane into antarctic, this appears to be some sort of defacto enforcement.

https://iaato.org/iaato-announce ... ne-use-by-visitors/
https://en.wikipedia.org/wiki/In ... tica_Tour_Operators
2-17 16:12
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Labroides
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The Saint Posted at 2-17 16:12
i saw that.  sure if you can find a way to get down there without going thru them, you can probably fly your drone, pet the penguins, bring back rocks....

all i know is if you are under the organization umbrella, you'll prob have to follow their rules.  not sure how they enforce things outside of contractual details but perhaps the o.p. can elaborate.  clearly this isn't restricted airspace or tfr's there but it appears the groups have come together to control all the tourists regarding drones.  unless you can take your own boat or plane into antarctic, this appears to be some sort of defacto enforcement.

The OP obviously isn't a tourist.
There are plenty of people at antarctic bases and they aren't there as tourists.
2-17 16:32
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The Saint
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Labroides Posted at 2-17 16:32
The OP obviously isn't a tourist.
There are plenty of people at antarctic bases and they aren't there as tourists.

sure i get that, per comment i made earlier.  just hard to believe an expedition or government entity of some sort are flying mavic minis that obviously can't handle it.  but i guess you might bring your own drone for fun....

"There are around 66 scientific bases in Antarctica, of which about 37 are occupied year round, the remainder are open during the summer and closed down for winter. There are about 4,000 people through the summer months and about 1,000 overwinter each year."
2-17 16:44
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m80116
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Cetacean Posted at 2-17 02:22
Aloha charles,

     Zbip might be on to something as well as confirming what Geebax, Labroides and some others mentioned.  The vision sensor may have a problem because of very low contrast due to all the snow.  The climbing for more altitude might be to find more objects to use for contrast in combination with GPS issues in the polar regions.  It would be better to fly over bare rocks so the vision sensor can use the rocks for contrast.  Your worst conditions for flying is the fresh snow you noted.  The best conditions for a soft crash landing is the same fresh snow.  No wonder you are having problems!

Without GPS nor downward vision sensors the drone still operates normally. If it climbs by itself it's almost certainly pressure related as it's the main factor for height calculation as explained by DJI in the past.
2-19 11:18
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Astro Bob
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Wondering if the downward facing sensors are confused by the snow and since the compass won't work it may resort to RTH which is obviously an impossible task.....but depending on what the RTH height was t would attempt to climb to that height and than get blown away. Temperature being so cold it would have a very short amount of fly time also.
I think about all you could do is turn off the RTH and if possible like on the MINI II, tell it to descend instead. Perhaps placing some back tape over the downward IR sensors would eliminate that confusing issue and just rely on pure unassisted manual flight mode.
But I think this would be asking a LOT out of that little drone to fly in those conditions and so handicapped.
2-19 18:20
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m80116
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The downward sensors are used for precise movement and positioning, afaik never for height estimates. If you miss the input form that dataset your drone can become more floaty as it is missing reference points on the ground... nothing dramatic.
2-19 21:51
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DroneJunkieQc
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Way too cold for most DJI drones, let alone the Mini which is rated at 0 Degrees Celsius or 32 Fahrenheit.
2-25 10:27
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AtPlaces
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Idk but -60 seems pretty harsh for even the most durable drones
2-26 07:25
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