Understanding Emergency/Forced Landing

[Dr.Sparky]

After sustaining damage from a forced landing due to battery depletion I want to understand exactly what the Mini 3 Pro is programmed to do.
It appears that a message to return to home is generated at around 15% battery and if that is ignored, the drone initiates landing in a matter of minutes .
It is really troubling that the drone may be above trees, over water, or as in my case a pitched roof.
Any idea of the parameters? DJIFLY doesn't allow you to set them. Also, can you steer the drone while it is emergency landing to attempt to avoid obstacles on the way down?

 

[Meta4]

After sustaining damage from a forced landing due to battery depletion

Didn't your drone lose power and fall from the sky?
In a forced landing, the drone lands while there is enough power to do that, so that it doesn't run out of power and fall to the ground.

I want to understand exactly what the Mini 3 Pro is programmed to do.

Your drone is monitoring distance from home and battery level and will suggest returning home when the battery level is getting close to the minimum to RTH from whatever distance out the drone is.

If you continue flying until the battery gets to around 10%, it will commence autolanding because that is usually better than flying until there is no battery left and falling.

It is really troubling that the drone may be above trees, over water, or as in my case a pitched roof.

That's why you monitor your battery level and don't leave the drone in such locations with a low battery.
Fly as if you were in the drone and make sure that you get back on the ground with a comfortable reserve.
That is very helpful if you run into unanticipated issues getting home.

Also, can you steer the drone while it is emergency landing to attempt to avoid obstacles on the way down?

Yes ... but your speed will be limited and you won't have enough power to fly as far as you might like.

 

[mavic3usa]

In order to find out exactly what your drone will do, may I suggest taking it to a big wide open field and putting it thru the paces and observe how it responds. That way you'll know exactly what to expect when you decide to take the risk of continuing to fly your drone on a low battery regardless the alerts thinking it's like a car and you can take it zero and then the car will just pull over wherever it is no damage. j/k

 

[Dr.Sparky]

Thanks so much for the info. I am definitely not trying to push the envelope. In fact, I am overly cautious and gun shy.
I was just surprised how rapidly the drone discharged. I clearly was unprepared but will heed any subsequent warnings.

 

[Meta4]

I was just surprised how rapidly the drone discharged. I clearly was unprepared but will heed any subsequent warnings.

It's unfortunate that the flight data was not available to show you what happened in your incident.
With batteries that have been lying around discharging for some tine. it's common for the battery level to falsely show 50% at launch, but crash to near zero within 30-40 seconds from launching.
That can cause a fall-from-the-sky incident if the drone isn't brought down immediately.

 

[MS Coast]

Thanks so much for the info. I am definitely not trying to push the envelope. In fact, I am overly cautious and gun shy.
I was just surprised how rapidly the drone discharged. I clearly was unprepared but will heed any subsequent warnings.

It's good practice to land with 20% or more capacity remaining in the battery. You'll avoid situations like the one you described and you won't be damaging your batteries. Their storage capacity declines if you frequently run the charge down too low.

 

[slup]

...message to return to home
...the drone initiates landing

Any idea of the parameters?

The low battery auto landing & the proposed RTH doesn't have fixed percentage parameters...

As already said, the landing is dependent on the height & the RTH is dependent on the distance to the HP.

All this can be found in the log from a flight with your drone. Below is taken out from my own Mavic Air 1 when I tried to get a complete picture of the different percentage levels for landing & RTH... your Mini 3 Pro is regulated in a similar way but perhaps with different values.

Here the low battery auto landing percentage the whole way up to 500m above the HP... note that my Air will start to auto land already at 27% when up on 500m... & it will never be lower than 10%.

(Click on the chart to make it larger)


And here regarding the proposed RTH battery percentage relative the distance to the HP... note that it seems to weigh in how much battery have been used in the past (the green graph doesn't have even steps in time. Here you also should know that the DJI software have no way of knowing if you will face a more battery consuming head wind on the way back... so this RTH can come to late if needing to fight a serious head wind on the way back, you can't just fly out until this RTH prompt & think the drone always will be able to return home before a low battery auto landing is initiated.

(Click on the chart to make it larger)

 

[Phantomrain.org]

After sustaining damage from a forced landing due to battery depletion I want to understand exactly what the Mini 3 Pro is programmed to do.
It appears that a message to return to home is generated at around 15% battery and if that is ignored, the drone initiates landing in a matter of minutes .
It is really troubling that the drone may be above trees, over water, or as in my case a pitched roof.
Any idea of the parameters? DJIFLY doesn't allow you to set them. Also, can you steer the drone while it is emergency landing to attempt to avoid obstacles on the way down?

One of the skills that you can learn is to Fight the Forced Landing by keeping your left stick up the entire time your moving forward with low battery , .

This takes practice but it will allow you to have a little more time in the sky, taking your drone to Zero Percent .

This is the way we fly everytime we go up into a Storm , to squeeze out every percent the Battery has .

Phantomrain.org
Gear to fly in the Rain. Land on the Water, and Capture the Holy Grayle.

 

[MavicAir2Marc]

Always start out with a fully charged battery, that will keep you from getting the surprise forced landings.