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What's the best thing to do after you realize you shouldn't have flown up into that fog?

I'm curious: If it says landing when it's high up, does that mean it will go down 1 meter and crash? Or does it have some detection based on motor output force or something else, not only sensors?
detectors :-) It will not fall out of the sky.
 
Rules are clear in his situation. But the info on how to handle the landing issues are good reading. I live in an area where it can be nearly clear one minute and 20 minutes later, Tule (ground) fog appears. Flying in fog to a safe landing can then become an issue.
 
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[...] if you take the drone up above the fog ,the downwards sensors can be fooled and think that the fog is actually the ground and then the drone will decide not to descend
My Mini will always descend when commanded to do so until it gets within about half a meter off the ground. At that point the infrared downward sensors prevent it from going any lower. If, while flying slowly low above the ground, it encounters an obstacle that comes closer than half a meter under the drone, the Mini will automatically rise up to avoid that obstacle.

So yes, when descending into the top of a cloud or fog, the sensor possibly might detect that as a solid surface and refuse to descend any lower. Holding the throttle down will trigger "Landing" and the drone will descend through the cloud or fog layer.

the aircraft is seeing the FOG as a solid surface and it very well could (as many others have found out the hard way) think it has landed and CUT POWER! Not a good idea.
It will NOT cut power. Whenever "Landing" is triggered, the drone will continue to descend from whatever its current height until it reaches solid ground. Power is cut only after it has registered a landing, in that it senses no further decrease in altitude in response to the descent power setting.

If it says landing when it's high up, does that mean it will go down 1 meter and crash?
No. When it says landing, it will continue to automatically descend from whatever initial height until landed.

Auto-landing can be interrupted at any point by giving it full up throttle, or by pressing Cancel in the app, or pressing the Cancel button on the controller. [Obviously, critical low-battery auto-landing is different, eh.]

I recently experienced a similar incident while flying close to a waterfall. The downward sensor on my Mini detected the spray coming off the waterfall and misinterpreted that condition as being less than 0.5m off the ground. Because I was holding the throttle down to descend at the time, that triggered auto-landing and the Mini commenced landing into the river. Eek!

Fortunately it happened at sufficient initial height that I had enough time to recognize what was happening and cancelled the landing. What really confused me was that I definitely did not have the throttle fully depressed at the time. I thought auto-landing was only ever triggered with the throttle held fully down. Not true.

There's a lot more info about that incident in this thread with videos and data plots,
LOSS of CONTROL OVER WATER **EXPLAINED**

But in particular, read this single post by @slup,
mavicpilots.com/threads/loss-of-control-over-water-explained.117029/page-3#post-1322010
He explains:
Applying full [down] throttle for a descent isn't needed in order to start the landing ... a couple preconditions needs to be met first though.

1. The VPS height should be 0,5m or lower
2. The throttle should in total be applied for descent longer than 3sec.
3. The throttle should sometime during the 3sec be positioned over [under] a certain threshold which seems to be in the ballpark of a throttle value of -8300 to -8500.
That was a real eye-opener. I tested and confirmed that with my Mini.

So, as it relates to this thread, if you are descending through heavy fog which the VPS sensors misinterpret as being within 0.5m of the ground, and you've being holding the throttle down for more than 3 seconds, and at some point the throttle is depressed to more than 85% down, THAT will trigger auto-landing!

If you want it to continue descending to auto-land where it's at, then no problem. Just let it do its thing and it will continue to descend until touching down on a solid surface. But if you really do not want it to land all by itself, press cancel immediately to stop the descent.
 
My Mini will always descend when commanded to do so until it gets within about half a meter off the ground. At that point the infrared downward sensors prevent it from going any lower. If, while flying slowly low above the ground, it encounters an obstacle that comes closer than half a meter under the drone, the Mini will automatically rise up to avoid that obstacle.

So yes, when descending into the top of a cloud or fog, the sensor possibly might detect that as a solid surface and refuse to descend any lower. Holding the throttle down will trigger "Landing" and the drone will descend through the cloud or fog layer.


It will NOT cut power. Whenever "Landing" is triggered, the drone will continue to descend from whatever its current height until it reaches solid ground. Power is cut only after it has registered a landing, in that it senses no further decrease in altitude in response to the descent power setting.


No. When it says landing, it will continue to automatically descend from whatever initial height until landed.

Auto-landing can be interrupted at any point by giving it full up throttle, or by pressing Cancel in the app, or pressing the Cancel button on the controller. [Obviously, critical low-battery auto-landing is different, eh.]

I recently experienced a similar incident while flying close to a waterfall. The downward sensor on my Mini detected the spray coming off the waterfall and misinterpreted that condition as being less than 0.5m off the ground. Because I was holding the throttle down to descend at the time, that triggered auto-landing and the Mini commenced landing into the river. Eek!

Fortunately it happened at sufficient initial height that I had enough time to recognize what was happening and cancelled the landing. What really confused me was that I definitely did not have the throttle fully depressed at the time. I thought auto-landing was only ever triggered with the throttle held fully down. Not true.

There's a lot more info about that incident in this thread with videos and data plots,
LOSS of CONTROL OVER WATER **EXPLAINED**

But in particular, read this single post by @slup,
mavicpilots.com/threads/loss-of-control-over-water-explained.117029/page-3#post-1322010
He explains:

That was a real eye-opener. I tested and confirmed that with my Mini.

So, as it relates to this thread, if you are descending through heavy fog which the VPS sensors misinterpret as being within 0.5m of the ground, and you've being holding the throttle down for more than 3 seconds, and at some point the throttle is depressed to more than 85% down, THAT will trigger auto-landing!

If you want it to continue descending to auto-land where it's at, then no problem. Just let it do its thing and it will continue to descend until touching down on a solid surface. But if you really do not want it to land all by itself, press cancel immediately to stop the descent.

It's been noted several times (on this forum and others) where DJI aircraft have indeed "registered" the aircraft has landed and powerdown in the scenario mentioned above.
 
Definitely no VLOS, however I'm very familiar with the property and knew there were no trees or wires or towers, and I was over land with no people or obstacles under it. I am kinda going on the maybe unsafe assumption, that if you're flying over your own property in clear airspace and you know there are no people or obstacles, and you're within a few hundred feet, it's okay to relax normal VLOS guidelines. I would love to hear from anyone if you think this could be unsafe as I'm always open to learning.
I think the key concept is that while you own your property, in the US you do not own the airspace over your property. The rules for the airspace are the rules for the airspace, regardless of who owns the property below.
 
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It's been noted several times (on this forum and others) where DJI aircraft have ind
Would you have links to any of the threads?
Taking what you say as correct, it is my experience that a drone will not shut down if there is movement, extending that .....if some horizontal movement were added to the descent into fog......?
 
It's been noted several times (on this forum and others) where DJI aircraft have indeed "registered" the aircraft has landed and powerdown in the scenario mentioned above.
I'll admit I may be wrong. That happens far too embarrassingly often, when I'm convinced I'm right but someone with factual examples proves me wrong. For example, I was totally convinced that auto-landing would only be triggered when the throttle is held full down, when in fact that's not true at all.

@slup explained what actually happens in such a way that I could then do my own experiments to confirm what he said is true.

All too often people state things as fact in these forums, with no actual proof to back it up. Those things are then repeated often enough by others until it becomes accepted truth.

I don't understand by what mechanism a drone could be fooled into thinking it had "landed" on a cloud and then powered down by itself. If you could post some links to previous examples, that would be appreciated.
 
My M2Z states “landing” when in RTH mode as soon as it starts descending from my RTH altitude(90 meters) and is directly over the takeoff spot. Am I misunderstanding something here?
 
My M2Z states “landing” when in RTH mode as soon as it starts descending from my RTH altitude(90 meters) and is directly over the takeoff spot. Am I misunderstanding something here?
You can select "landing" from any height you please, and the drone will continue slowly descending until touching down on something solid.

But this question was different. If the downward height sensor of the VPS system detects it is within 0.5m (~2ft) of touching down onto anything, i.e. in fog or descending into the top of a cloud, will the drone then only descend another 2ft and automatically shut off its motors thinking it has landed, or will it continue to safely descend in auto-landing mode until touching down on solid ground?

There are a couple of scenarios in question here. If the drone is happily flying through a fog layer or above a cloud, the VPS system might detect that as a solid obstacle within 2ft of its underside and block the drone from descending any further. But one should be able to over-ride that feature by holding the throttle closed to initiate an auto-landing down through the cloud.

Another scenario might be that an auto-landing has already been selected and the drone then descends toward a fog layer or cloud. If Landing Protection is enabled the VPS system might, for whatever reason, decide the cloud top is an "unsuitable landing location" and prevent the drone from descending any further, leaving it hovering there. But you would get a warning message to that effect asking for your confirmation that you wish it to continue "landing" anyway.

But what if that scenario happens subsequent to a loss of control signal? You'd never see the "Unsuitable Landing Location" warning message, nor be able to confirm that you wish to continue the landing. The drone might stay there hovering until a critical low battery forces it to land. So then the question is, does it think it only needs to descend 2ft to land in the cloud top, and thus waits for only enough critical battery left to descend 2ft? In that case, yes, the motors might shut off when the battery is depleted and it will fall through the cloud, no?

In any normal case, it doesn't just measure an additional 2ft drop in altitude and then shut off the motors in mid-air. It will continue descending until it senses no further drop in altitude corresponding with the motors turning at less-than-hover speed.

In the example I linked to in Post#24 above, the VPS sensor of my Mini detected spray from the waterfall, and the flight log at that time showed a VPS-height reading of only 2ft. I was holding the throttle more than 85% down at the time, backing and descending toward my landing location. With the throttle held down and a VPS-height showing only 2ft, that triggered an Auto-Landing.

I took me all of four seconds to figure out what the beeping warning noise from my controller meant, during which time the Mini had already descended 15ft in landing mode toward the river. Luckily I managed to cancel auto-landing and resume control with plenty of height to spare, about 40ft still above the water.

The point is, the Mini's VPS system detected the mist as "something" within 2ft of its underside. Because I was holding the throttle down at the time, it automatically triggered "landing". The Mini did not descend only another 2ft and automatically shut off its motors thinking it had landed. It did descend a full 15ft in the time it took me to cancel the landing. If I had done nothing to cancel it, the Mini would have continued descending another 40ft and landed in the water.
 
I think the key concept is that while you own your property, in the US you do not own the airspace over your property. The rules for the airspace are the rules for the airspace, regardless of who owns the property below.
Thanks for that info. I was right up at about tree top level - maybe slightly higher but not by much. Do I not control the airspace from the tops of my own trees down?
 
Thanks for that info. I was right up at about tree top level - maybe slightly higher but not by much. Do I not control the airspace from the tops of my own trees down?
My understanding is no. You control the airspace within your house, but as soon as you go outside, the FAA controls it all. I'm not a lawyer, but I've heard there is some ambiguity in case law around this.

Note that this is the reason we can fly our drones in most places. People/local governments can regulate where we stand when we fly our drones, but only the FAA can regulate what airspace we fly them in.

There are privacy regulations in many places that prevent us from abusing this freedom to, for example, take photos through people's windows, or for that matter film them swimming in their back yard pool.
 
I know better now, but I've got questions.

It was a foggy morning when I thought I'd shoot a 320-foot dronie off the back deck on a foggy morning. No problems filming the actual dronie, and it even was flying back on its own just fine. But when it got close to the starting point, I took over manual control and tried to land. That's when I discovered the Air 2 saying, "Landing" when it was 30 feet up. It didn't look like that much fog, and it was only 30 feet up, but it couldn't tell where the ground was.

Having never encountered this situation before, my immediate thought was, "it's going to think it's on the ground at 30 feet up and then cut power and crash." So I cancelled the landing, tried again, and the same thing, and I cancelled again. Eventually I figured out that if I just kept it trying to land, it wouldn't cut power, so I moved to a safe place and landed from 30 feet up. So I've got questions now:
  1. Is there a way to get the Air 2 to descend normally when the bottom sensors get fooled by fog?
  2. Can I switch the bottom sensors off mid-flight, then maybe switch them on again?
  3. Will a return to home in the fog work?
  4. Is there any way to fly safely in fog?
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I had virtually the same experience. Morning fog, local wetlands, great pix.

But when I went to RTH the drone repositioned correctly over the landing spot, but it would not come down. Battery was at 10%. :-| The controller kept beeping and (not sure if I remember this correctly) I got a message to the effect that there was an obstacle below.

In retrospect I suppose either the fog was so dense it was being perceived as 'hard' or (more likely) the sensors were too wet. I was lucky that a light breeze cleared the air of the LZ and the drone finally landed. When I picked it up it was wet all over. Only THEN read the DJI recommendations to not fly in the fog!

I never thought about changing modes to disable the sensors but that would likely have resolved my issue. Personally, I've deprioritized fog flights for the time being. My nerves couldn't take it again. ;-P
 
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I know better now, but I've got questions.

It was a foggy morning when I thought I'd shoot a 320-foot dronie off the back deck on a foggy morning. No problems filming the actual dronie, and it even was flying back on its own just fine. But when it got close to the starting point, I took over manual control and tried to land. That's when I discovered the Air 2 saying, "Landing" when it was 30 feet up. It didn't
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Its kind of a cool shot so I suggest not flying all the way into the fog. You get your shot and you get your drone back, hassle free
 
Thanks for that info. I was right up at about tree top level - maybe slightly higher but not by much. Do I not control the airspace from the tops of my own trees down?

Currently, the FAA and only the FAA controls Airspace unless you're inside a structure. The moment you go outside you are flying in the National Airspace System (NAS) which is ONLY controlled by the FAA.
 
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