RTH crash

[Kajtek]

There are limitations to what the IR sensors can do and what conditions they can work with.
I'm tired of typing the same thing over and over to someone who just doesn't want to understand.

Many times I have written that I know what limitations are. It must be that English is my second language that I was not clear enough and you did not understand me.

During an autolanding process, several scenarios can lead to a drone crashing accident, resulting in undesirable outcomes. The three main scenarios for failure are as follows:

1.Malfunction: A technical issue or failure in the drone's hardware or software can disrupt the autolanding process, leading to an uncontrolled descent or collision.

2.Operator error interfering with the automation process, operating the drone outside of the limitation of the system, drone not inspected before flying like damaged drone, dirty sensors, etc.

3.Failure of the automation system: This could happen if there is a limitation in the autolanding system that was not expected or described before, or if the environmental factors were not described in the manual and caused the crash.
It is essential for the manual or documentation accompanying the drone to provide clear descriptions of the conditions under which the automatic process may fail. This information will help users operate the drone safely and avoid potential accidents. The manual should outline any limitations, operational boundaries, and environmental factors that may affect the drone's autolanding capability.

The manual devotes 5 pages to RTH and limitations. Page 15-20 https://dl.djicdn.com/downloads/DJI_Mini_3_Pro/UM/DJI_Mini_3_Pro_User_Manual_EN.pdf

Whether the system failed or not depends on whether the drone's behavior aligned with the manufacturer's communicated limitations.

I hope that this will clear misunderstanding.

 

[Meta4]

Many times I have written that I know what limitations are. It must be that English is my second language that I was not clear enough and you did not understand me.

The only malfunction was the operator not understanding the limitations and not believing that there was no malfunction.
But as I've said several times, you could have landed exactly where you wanted the drone to land, much smarter than the dumb autoland.

That's it from me.
I've put in too much effort and you don't want to hear anything that goes against what you want to believe.

 

[lostit]

RTH is for when the drone has lost comms and/or you've lost visual, I wouldn't land with it unless in a clear open field.

 

[Droning on and on...]

@Kajtek, you seem to be insisting on 100% complete characterization of system behavior under all possible circumstances. That's not possible.

There are myriad circumstances in the real world that DJI never tested, and the system will operate in error, and may crash, all while functioning absolutely normally.

You've discovered two things: 1) A bush that was an instance of those corner cases that can defeat the landing protection system. 2) You don't believe it for some reason, despite the evidence.

That's it. There's nothing more to this.

 

[baddog]

I just received the Mavic Mini 3 Pro and I'm using the RC Pro Remote that I also use with my Mavic 3. The first flight went mostly smoothly, except for one issue. When I initiated the Return to Home (RTH) function, the drone wanted to land 3 meters away from the starting point, which wasn't as precise as I'm accustomed to with my Mavic 3. As it started descending and deviated from the starting point, I clicked cancel and manually landed it.

During the second flight, the RTH function once again wanted to land the drone 3 meters away from the starting point. This time, when I tried to cancel it, it didn't work. It seemed like the drone actually accelerated its descent (though that might have been my impression) and crashed into a bush that protected it. If there had been concrete or hard ground instead of the bush, the drone would have been damaged.

The automatic landing should have slowed down and landed the drone gently. At least, that's what my Mavic 3 does.

Additionally, I've noticed that there's no discernible difference between cine mode and normal mode. Both modes seem to have similar speeds.
Attached the log file. I cannot find explanation what happened. Anybody can analyze the last seconds?
How do I contact DJI. I found only options to send the product. Is there an option to send them files just for analysis?

The Mini 3 Pro has different RTH procedures based on its distance from the home point.

 

[Kajtek]

@Kajtek, you seem to be insisting on 100% complete characterization of system behavior under all possible circumstances. That's not possible.

There are myriad circumstances in the real world that DJI never tested, and the system will operate in error, and may crash, all while functioning absolutely normally.

You've discovered two things: 1) A bush that was an instance of those corner cases that can defeat the landing protection system. 2) You don't believe it for some reason, despite the evidence.

That's it. There's nothing more to this.

Thank you for pointing out that there is no perfect automatic system, I know it and I mentioned it before. My goal was to identify the limitations of the system that caused the crash, and you are right, I did discover rare circumstances that defeated the system. This is exactly what I wanted to know, and I found out.
I have no idea why you think that I didn't believe in it, unless it was my English that was not clear. The system was defeated, as you say, which means it failed in that specific instance.

 

[Kajtek]

The only malfunction was the operator not understanding the limitations and not believing that there was no malfunction.
But as I've said several times, you could have landed exactly where you wanted the drone to land, much smarter than the dumb autoland.

That's it from me.
I've put in too much effort and you don't want to hear anything that goes against what you want to believe.

Thank you for your input. Just a small correction, however. I did not insist that it was a malfunction, as you seem to imply. I was trying to find out why the system did not perform to expectation. Rare circumstances that fooled the algorithm do not constitute a mechanical malfunction.

 

[Kajtek]

RTH is for when the drone has lost comms and/or you've lost visual, I wouldn't land with it unless in a clear open field.

RTH is for more than that. You approach is safe.