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Mini4 Pro Landing Failure

kinetix

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While RTH with a low battery, I cancelled RTH at <100' so that I could land manually. The drone stopped a few feet off the ground and would not land. I was landing on a paved parking lot but the controller said something like "unsuitable landing area". The battery was running down and the drone would not respond to inputs to move in any direction. I pushed what I thought was the land button and the drone lifted and began flying toward a nearby building. I couldn't get it to stop or turn and it hit the side of the building and crashed. Thankfully I have DJI Care. But I am concerned about the way the drone behaved when it wouldn't land, why it turned and flew toward the building, and why the collision avoidance didn't kick in. Lots of questions.
 
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You should post the flight log, just in case the crash was NOT your fault and was due to something that should be covered by warranty.
What controller did you use?
If relevant what phone did you use?
What computer type do you have, Mac, Windows, Linux etc.?
 
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As
@Yorkshire_Pud
I think he meant down load your flight data?

These Members are good on this. and we all learn. 👌

I would look at this thread.

If you got questions, you will get some help.

Rod ..
 
Thanks for the responses.

What controller did you use? The RC2
If relevant what phone did you use?
What computer type do you have, Mac, Windows, Linux etc Windows

How can I download the flight data?
 
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I guess that that was from looking at the card from the drone, would that be correct?
To get the logs from the controller you may need to either browse the controller's file system with an built in file browser, look for "DJIFlightRecord" and move them or copy them to the memory card in the controller or connect the controller to you computer via USB and run a search for DJIFlightRecord on the phone using windows.
This might be of some use
or post 7 in
or
 
"unsuitable landing area"
Did you touch the "unsuitable landing area" warning ?
I have the recollection that when I see that warning or similar I have to touch the warning and confirm, in a subsequent window, that I want the drone to land.

Ahh edit, just managed to test this, I was mistaken. On touching the warning, the warning is cancelled but the drones ( 2 x Mini 2) continued to hover and I had to command descent by holding the throttle closed.

Of course, when I want to test this, now, the drone is finding the landing area suitable even when it is not and I am not getting the warning lol.
 
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All these flights modes, really I just get lost?

What Is fun is watching that type of playback, and when us Humans go in that Panic mode. :rolleyes:
Been there many times, I know there will be more. It would be very cool is to see the operators face at the same time. :)

As many others know I have twisted humor, I try to proud the person to share the log. Thumbswayup

Everybody can Learn !!

Rod ..
 
You manually brought the drone down to two feet above the ground and released the left stick.
The drone had been directly above the homepoint, but as you descended it drone drifted to about 35 ft from the homepoint.
You left it hovering and pulled left stick down three times for about a second, then left it hovering for 20 seconds.

At 19:05.0 there was a warning of Low Battery, drone would return to home and the Flight Mode changed to RTH.
Shortly after this, you pulled the left stick down again and then the drone started to rotate to point towards the homepoint.
As it started to fly towards the homepoint, you fought against RTH to lower and turn the drone.
The drone returned to the homepoint and had a slow speed collision at 19:21.5.
The drone stopped a few feet off the ground and would not land. I was landing on a paved parking lot but the controller said something like "unsuitable landing area".

The battery was running down and the drone would not respond to inputs to move in any direction. I pushed what I thought was the land button and the drone lifted and began flying toward a nearby building. I couldn't get it to stop or turn and it hit the side of the building and crashed.
You got the impression that the drone wouldn't respond to your joystick inputs because the drone was trying to RTH.
You didn't cancel the RTH and tried to fight against it.
At the time of the collision, GPS indicates the drone was two feet from the recorded homepoint.
It's not safe having the homepoint close to obstacles

But I am concerned about the way the drone behaved when it wouldn't land,
I can't see an unsuitable landing spot message in the data, but if there was one, the correct action would be to move to a different spot and try landing there but you kept the drone at the same spot.
why it turned and flew toward the building
It went to Low Battery RTH and was following the RTH programming.

 
Meta4,

Thanks for the analysis.

Regarding "as you descended it drone drifted to about 35 ft from the homepoint". I don't recall it drifting
more than a foot or two through the entire descent and it was very close to the HP when it stopped responding. I panicked when it wouldn't land. It went into the low battery warning again and I tapped what I thought was the land button on the left, maybe it was the return to home. I was still within a couple of feet of the home point when it turned and rose up abruptly flying away from the home point and into the bldg that was 10'-15' away. Trying to think of how I could have reacted differently and prevented the crash.

Doug
 
Trying to think of how I could have reacted differently and prevented the crash.
If you had cancelled the RTH, you would have had full control.
But trying to control the drone when RTH is controlling it isn't going to work.
 
But trying to control the drone when RTH is controlling it isn't going to work.
Are you sure about that?
The manual does not cover every scenario but it does say.
"Auto landing cannot be canceled, but the remote controller can be used to control the horizontal movement and the descent speed of the aircraft during landing. If there is sufficient power, the throttle stick can be used to make the aircraft ascend at a speed of 1 m/s.
During auto landing, move the aircraft horizontally to find an appropriate place to land as soon as possible. The aircraft will fall if the user keeps pushing the throttle stick upward until the power is depleted."

With either the Mavic Mini or a Mini 2 I had the home point on one side of the house and during an RTH auto landing, when the drone was about 3 or 4 ft above the landing point, I forced the drone to climb, fly over the roof of the house and land on the other side of the house.
Though I doubt that I did this at low battery levels.
I was somewhat surprised that once I released the throttle and elevator etc. it just descended where it was, I sort of half expected it to 'RTH again'.
 
Are you sure about that?
Yes
The manual does not cover every scenario but it does say.
"Auto landing cannot be canceled, but the remote controller can be used to control the horizontal movement and the descent speed of the aircraft during landing. If there is sufficient power, the throttle stick can be used to make the aircraft ascend at a speed of 1 m/s.
During auto landing, move the aircraft horizontally to find an appropriate place to land as soon as possible. The aircraft will fall if the user keeps pushing the throttle stick upward until the power is depleted."
My comment was about fighting against RTH.
Your response is about autolanding.
Those are two different things.
 
"Auto landing cannot be cancelled, but [...]
There is a difference between Auto-Landing versus Forced-Landing.

Auto-landing, whether selected by menu choice or RTH, can be interrupted at any time by raising the throttle stick, or tapping the cancel button. Forced-Landing, whether due to low battery or geofencing, cannot be cancelled but it can be delayed by raising the throttle stick.

During RTH the Mini follows a straight path toward Home. Wiggling the control sticks cannot make the Mini deviate from that straight path toward Home, but RTH can be cancelled at any time by tapping the cancel button.

I tapped what I thought was the land button on the left, maybe it was the return to home.
That would immediately cancel RTH and cancel an Auto-landing, putting you back in control.

"Auto landing cannot be cancelled, but the remote controller can be used to control the horizontal movement and the descent speed of the aircraft during landing. If there is sufficient power, the throttle stick can be used to make the aircraft ascend at a speed of 1 m/s.
During auto landing, move the aircraft horizontally to find an appropriate place to land as soon as possible. The aircraft will fall if the user keeps pushing the throttle stick upward until the power is depleted."
During the descent phase of RTH once the Mini has started descending straight down to auto-land, or even descending during a Forced-Landing, you can control its horizontal movement to a more suitable location and slow its descent or even make it climb. But whenever you release the sticks it will continue its descent to land in that new location. Of course if it's a critically low battery condition, there is a finite limit to how long you can coax it to stay airborne while you're holding the throttle stick up.

With either the Mavic Mini or a Mini 2 I had the home point on one side of the house and during an RTH auto landing, when the drone was about 3 or 4 ft above the landing point, I forced the drone to climb, fly over the roof of the house and land on the other side of the house.
Though I doubt that I did this at low battery levels.
I was somewhat surprised that once I released the throttle and elevator etc. it just descended where it was, I sort of half expected it to 'RTH again'.
Yup, if you don't touch the sticks, it will RTH and land normally at the Home Position. But, during the RTH descent to landing, (assuming you have enough battery left), you can redirect the Mini to a different landing location and, after you release the sticks it will continue its Auto-landing at that new location.
 
For what it's worth, I recently had an 'unsuitable landing area' situation with the Mini 4 Pro, right above the landing pad where I took off from beginning the flight. It was getting dark so I contributed it to failing light conditions. Switching to sport mode gave me full control to manually land.
 
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