It was a foggy day today and i dicided to try and get some interesting shots. As you would see from the log i was flying low with no problems. there was no need to go high as because of the fog. In one point at 4m 20sec i got to 35ft and tried to get it lower but it would not fly down and few seconds later it started a forced landing. i cenceled it and tried again to go down the forced landing again started again. in the end i just got the drone back to me and let it foced land to a hight i was ok with and continued with flying at low altitudes.
This happened every time i got some hight and tryed to get it down. I tryed to not push the stick all the way down but in that case the dron would just not go down.

Here is the log

https://www.phantomhelp.com/logviewer/QGXYM95KLRROLYPA6OE2/

I haven't looked at the log yet, but:  If you were flying in fog, might not water be collecting on the electronics in the drone, creating short circuits?  I don't think anything is sealed in these little drones.  Flying one in rain or fog seems to me like operating a PC or TV set out in the rain.  I've worked on electronics for 40 years.  I wouldn't dream of flying my Mini in fog, rain, mist, snow, or any wet weather unless I knew every contact, connector, circuit board, etc., was completely encapsulated or sealed in some way.

Also:  Water getting on the blades might affect them as well.  I recently did a bunch of testing because I had a similar problem where my Mini wouldn't fly at any height over about 1 foot above the floor in my office.  It turns out that some propeller damage was the likely culprit.   Water or ice forming on the props would have a similar effect.

And a question:  Has the drone resumed flying properly now that it has had a chance to dry out?

Sigmo Posted at 1-12 18:41
I haven't looked at the log yet, but:  If you were flying in fog, might not water be collecting on the electronics in the drone, creating short circuits?  I don't think anything is sealed in these little drones.  Flying one in rain or fog seems to me like operating a PC or TV set out in the rain.  I've worked on electronics for 40 years.  I wouldn't dream of flying my Mini in fog, rain, mist, snow, or any wet weather unless I knew every contact, connector, circuit board, etc., was completely encapsulated or sealed in some way.

it was flying fine when at 3-5 feet. no problems going up/down. and i flu for 20 minutes after that and again only problem was when i got at (maybe) 30ft. again left/right/forward/back/up all fine, just when i try to go down it starts forced landing. weird.

Sigmo Posted at 1-12 18:51
Also:  Water getting on the blades might affect them as well.  I recently did a bunch of testing because I had a similar problem where my Mini wouldn't fly at any height over about 1 foot above the floor in my office.  It turns out that some propeller damage was the likely culprit.   Water or ice forming on the props would have a similar effect.

And a question:  Has the drone resumed flying properly now that it has had a chance to dry out?

no fly problems when at 3-7ft . this was filmed at the end of the fly sesion https://www.instagram.com/p/B7PnW7bgs-o/ and the bug started again when i tried to go above the tree. not sure what the height is.

Sigmo Posted at 1-12 18:51
Also:  Water getting on the blades might affect them as well.  I recently did a bunch of testing because I had a similar problem where my Mini wouldn't fly at any height over about 1 foot above the floor in my office.  It turns out that some propeller damage was the likely culprit.   Water or ice forming on the props would have a similar effect.

And a question:  Has the drone resumed flying properly now that it has had a chance to dry out?

can't edit the post. there was some ice on the blades (little but there was some) but you can see in the video that there was no problems in flying

Thanks for the help

I think even a tiny amount of frost on the props would likely affect this tiny drone.  I'm at a bit over 5000 feet elevation here, and noticed the problems when flying with the prop guards in place, so the Mini struggles with not only the thin air here, but also the added weight of the prop guards, and that's part of what makes everything extremely critical for me, and why the damage to the prop blades probably create more of an issue for me than it might for someone flying at a lower elevation and without the prop guards in place.

Having said that, the blades' shape is extremely critical.  I can imagine frost or "icing" forming on the blades that could alter the shape ever so slightly, and still cause it to have problems getting enough lift at any elevation, and without the weight of the guards.

But, what you're describing is the drone initiating an auto landing, not a loss of lift.  So that makes me think of problems that might be related to the fog/moisture tricking something in the drone to keep trying to auto land.  Condensation shorting something out a bit by creating some conductive paths that shouldn't exist might explain this.  Or maybe the downward facing sensors were being tricked in some way.

It's amazing what all goes on in these little drones, and it makes troubleshooting things somewhat difficult because there is so much being processed.

The log does say "auto landing".  So I guess I wonder what are all of the things that are supposed to trigger an auto landing, and which of them might be triggered by moisture.

As I understand it, there is a small camera looking down to detect patterns and help the drone maintain its hovering position or move properly when it's close to the ground.  Supposedly, this works only below 30 meters (if I'm recalling correctly).  In addition, there is an infra-red emitter and an infra-red detector both looking down as well.  I've read that that's what the two larger round, dark "lenses" are on the bottom of the Mini.  I think this is used to judge distance above ground when close to the ground.

Is it possible that when flying upwards more into the fog, this downward-looking optical distance sensor was fooled by reflections off of the fog particles such that it thought it was right at ground level, so it initiated the auto landing?  That's just a wild speculation, but might explain what you experienced.

The data clearly shows that the fog or the light on the fog was confusing your downward looking sensors.
You held the left stick down and it slowed the descent.
The sensors were indicating that the drone was less than a metre above something.
You held the left stick down after VPS had stopped the descent and that forced the drone to land.

I think this is *exactly* what happened to you. Bottom sensors were seeing fog and thought it was land.

Labroides Posted at 1-12 22:22
The data clearly shows that the fog or the light on the fog was confusing your downward looking sensors.
You held the left stick down and it slowed the descent.
The sensors were indicating that the drone was less than a metre above something.

This is my first ever drone, so not sure what to expect. my first thought was the sensors were tricked but it was not that bad, i could see the drone with my eyes. I also had a weird flyaway attempt in my first and only night flight. the drone just wanted to go up as it thought it is really close to the ground. So mavic mini not that good in low visibility conditions.

Where do you see in the log what the sensors were "thinking" and what buttons/sticks were used?

Thanks to all of you.

bil.prag Posted at 1-13 05:33
This is my first ever drone, so not sure what to expect. my first thought was the sensors were tricked but it was not that bad, i could see the drone with my eyes. I also had a weird flyaway attempt in my first and only night flight. the drone just wanted to go up as it thought it is really close to the ground. So mavic mini not that good in low visibility conditions.

Where do you see in the log what the sensors were "thinking" and what buttons/sticks were used?

Where do you see in the log what the sensors were "thinking" and what buttons/sticks were used?
The joystick inputs are visible in the spreadsheet you get when you click on Download CSV.
You can find the VPS data if you click Download Verbose CSV.

Labroides Posted at 1-13 05:53
Where do you see in the log what the sensors were "thinking" and what buttons/sticks were used?
The joystick inputs are visible in the spreadsheet you get when you click on Download CSV.
You can find the VPS data if you click Download Verbose CSV.

thank you.

Hiya,

see my chart ; see that the VPS height is measuring the fog...

With VPS height measuring < 0.5 mtr AND 100% stick down = you commanded an autolanding.

cheers
JJB

just tried to test it again. few times worked fine, once started an forced landing. in the end it just went crazy and started dropping down (i liked it more when it activated the forced landing ) It was hovering while i was looking at the menu and it just started dropping, no reaction to the up stick movement, it bounced, and then i got him to land. the temperature was +3C and no wind at all, with fog maybe even less than yesterday

https://www.phantomhelp.com/LogViewer/KN8CGGGYFY22F50P0VPH/

so i should only fly mavic mini in bright day, no cold, maybe some wind? sorry for bothering but this is my first drone and i am learning.

   

Fog and water can or trick the VPS system into thinking it is closer to "land" that it actually is. I've seen a video of a guy flying his mini a few feet over a stream and it actually tried to follow the stream where the VPS was trying to lock onto what it thought was land. But the land was moving, and so did the mini. I've flown in fog once before and didn't have any real issues. But I wasn't hovering less than a meter above the ground holding down on the stick, at least not until I wanted it to land anyway. Environments like this can be tricky to learn how to fly in, but once you do, fog makes for a very interesting story to show to people. Best of luck and safe flying!!

JodyB Posted at 1-13 07:59
Fog and water can or trick the VPS system into thinking it is closer to "land" that it actually is. I've seen a video of a guy flying his mini a few feet over a stream and it actually tried to follow the stream where the VPS was trying to lock onto what it thought was land. But the land was moving, and so did the mini. I've flown in fog once before and didn't have any real issues. But I wasn't hovering less than a meter above the ground holding down on the stick, at least not until I wanted it to land anyway. Environments like this can be tricky to learn how to fly in, but once you do, fog makes for a very interesting story to show to people. Best of luck and safe flying!!

video is interesting that was the reason i wanted to try to fly. maybe i will try the fog when the temperature is not that close to 0.
now i can just wait until the weather gets better.
Learning as i go.
Thanks

bil.prag Posted at 1-13 11:13
video is interesting that was the reason i wanted to try to fly. maybe i will try the fog when the temperature is not that close to 0.
now i can just wait until the weather gets better.
Learning as i go.

I agree, videos with fog/snow/water are very interesting

Yes, I would like the feature in the flyapp to switch off the VPS sensors (possible in go 4 app I think ?) . Currently I always have to take tape with me if I want to fly 1/2 feet over water or through a concrete pipe. Or in fog, if there is a fog day here.  :-)

jonny007 Posted at 1-13 12:04
Yes, I would like the feature in the flyapp to switch off the VPS sensors (possible in go 4 app I think ?) . Currently I always have to take tape with me if I want to fly 1/2 feet over water or through a concrete pipe. Or in fog, if there is a fog day here.  :-)

that really works? i mean i would probably not do it but it is nice to know

bil.prag Posted at 1-13 13:24
that really works? i mean i would probably not do it but it is nice to know

Of course, but you just have to be more careful, especially indoors, when neither GPS nor VPS is active. Then the Mini behaves like a 20$ small toy drone without any stabilization ... also see whart happened at 4:58 in the video. But I think this is the only way to fly or hover 1 inch above the ground. ;-)

Definitely I'd like an option to switch off the VPS sensor.

I begin to think all these intelligent technologies are implemented like in Boeing's 737 max. Sometimes they do more harm than good.

Manual override MUST always be possible at any time.

Hi, thank you for reaching out. Can you please clarify if you still experience the issue that you had mentioned? Also, can you please try to fly the drone in a location wherein there is no fog to see if the problem persists. Please don't hesitate to reach us if you have other inquiries or concerns. Thank you for your support!