Why did my Mini 4 Pro crash?

mobilehomer · Dec 16, 2023

If you watch the playback on Airdata, the instant the blocked motor warning pops up, the drone is at the tree.

slup · Dec 16, 2023

mobilehomer said:
... the instant the blocked motor warning pops up, the drone is at the tree.

It's not conclusive if looking into the data & exactly where the major attitude changes happens & where the messages about Blocked motor & Not enough force comes in...

In below chart I've placed the chart marker as close to 1256,9sec I could... it's there the blocked motor comes. It's also from there the major attitude changes starts. From there on we also have a Not enough force message lasting until the log ends.

If looking at where the drone is when all happens on the 2D sat map (all 3 windows below is synced) it look like the drone already have passed those suspicious trees. If we then also look at the 3D generated picture (further below) of the flight path in Google Earth it's likely that a 2D picture can trick us to believe that the trees was closer than they were in reality.

It's a mystery what the drone collided with if nothing obvious exists where all starts... the OP is the only one that can draw more precise conclusions here I believe. He have so far not described where those mentioned light poles where located...

(click on the pic below to make it larger, then click again to make it even larger... there the small text from the message stream window should be readable )

mobilehomer · Dec 16, 2023

slup said:
It's not conclusive if looking into the data & exactly where the major attitude changes happens & where the messages about Blocked motor & Not enough force comes in...

In below chart I've placed the chart marker as close to 1256,9sec I could... it's there the blocked motor comes. It's also from there the major attitude changes starts. From there on we also have a Not enough force message lasting until the log ends.

If looking at where the drone is when all happens on the 2D sat map (all 3 windows below is synced) it look like the drone already have passed those suspicious trees. If we then also look at the 3D generated picture (further below) of the flight path in Google Earth it's likely that a 2D picture can trick us to believe that the trees was closer than they were in reality.

It's a mystery what the drone collided with if nothing obvious exists where all starts... the OP is the only one that can draw more precise conclusions here I believe. He have so far not described where those mentioned light poles where located...

(click on the pic below to make it larger, then click again to make it even larger... there the small text from the message stream window should be readable )
View attachment 171081

View attachment 171082

The capture from Airdata -

slup · Dec 16, 2023

mobilehomer said:
The capture from Airdata -
View attachment 171086

Yeah, that's the same spot I show through CsvView... at 1256.9sec into the flight. And it's not conclusive that the tree had anything to do with the incident, not impossible (a very long branch low down hanging over that foot path?) but the drone seems to be clearing the tree (especially if you look at the GE 3D view. Would be good if the OP could shed some light around those light poles he mentions.

SWTSU · Dec 16, 2023

Yorkshire_Pud said:
It is sensible to have at least one back up drone ........ that's my excuse and I'm sticking to it

Yup, started with an Air 2S, then got a FPV, and to back up the back up, I got an Avata… just in case.

aeciolemos · Dec 17, 2023

Yorkshire_Pud said:
It is sensible to have at least one back up drone ........ that's my excuse and I'm sticking to it.

I think you are absolutely right. I need to keep a spare!

aeciolemos · Dec 17, 2023

Felix le Chat said:
In the video you tagged, the drone crashed itself by doing exactly what you experienced: it shifted from the relatively safe route it had been instructed to favour and 'decided' to head straight into a bush to the right. As already stated, O/A is okay for the big stuff. Even then I'd never trust it fully.

I went back and watched it again. You are right, it did just that. I guess it is a software issue that DJI needs to address, where the drone decides to do something it was told not to do. GOing forward O/A will be for big objects. I will go back to how I flew before, staying away from trees, twigs, branches and such. I want to run a few more tests with what I can trust it to do with O/A - however for my other acrobatics, I have purchased an Avata, which seems to be better at both handling tight spaces AND recovering from crashes. Some people say it is almost indestructable under normal circumstances.

aeciolemos · Dec 17, 2023

Kenji_Tulsa said:
I just bought a Mini 4 Pro haven't flown it yet. Thanks for sharing some really valuable data for a newbie like me.

Hi @Kenji_Tulsa you are welcome. It is good to learn from other's mistakes!

I have been flying DJI drones since the Mavic Mini and I had never had a drone with Obstacle Avoidance, so I always trusted my manual piloting abilities, which is obviously better than the drone's ability to stay safe! I guess the bottom line is, take it with a grain of salt and don't trust that the drone is "smart". As another member mentioned, the marketing videos make it seem amazing when the truth is, it is still too dumb to stay out of harms way! Maybe the Mini 5 or 6 or 7....

aeciolemos · Dec 17, 2023

mswlogo said:
Since it was in follow me mode (not fast) and no mention of wind and not recording. Was that battery drain rate normal?

It seems it was, yes. There was no wind that day, it was at about 4m from the ground and it landed on the grass, so all in all, it was flying in perfect conditions. I am still kicking myself for not hitting record! It would have been epic!

The logs don't show that it crashed due to the battery dieing.

aeciolemos · Dec 17, 2023

smbishop said:
Ian in London's last 3 videos go over OA. He has settled on 'by-pass' and "nifty - on". These are the settings I am currently using as well.

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As soon as my drone is back, I will try that. I won't risk crashing it again, but I will try to fine-tune and use it more carefully. Thanks! I'm heading over to watch those!

aeciolemos · Dec 17, 2023

bobbydoug said:
Ice on your rotors? Just a guess based on temp and humidity.

I don't think so. It was about 10oC and I was flying low. I mean, I was wearing a snow jacket, but I am usually colder than people around me. Two guys were jogging in t-shirts LOL I guess I am just that old man that is always cold.

aeciolemos · Dec 17, 2023

Dmcvey said:
Gravity

Definitely the cause. If not for Gravity, it would have just hovered

aeciolemos · Dec 17, 2023

mswlogo said:
Although I think it was too warm for ice. It doesn’t look like it flew off in random directions.

Be nice to know if it was one motor or multiple motors.

I think DJI will tell me that once it is analyzed. I did upload all the logs to them as well. I think it just decided to fly behind me for some reason when I clearly told it to follow from the back/left at about 7-8o clock position. There were trees and I do think it crashed into the dry, leafless twigs on the branches. That is the most logical explanation.

mswlogo · Dec 17, 2023

aeciolemos said:
I think DJI will tell me that once it is analyzed. I did upload all the logs to them as well. I think it just decided to fly behind me for some reason when I clearly told it to follow from the back/left at about 7-8o clock position. There were trees and I do think it crashed into the dry, leafless twigs on the branches. That is the most logical explanation.

Maybe it was trying to be artistic.

aeciolemos · Dec 17, 2023

HoozierDroneDaddy said:
You mentioned light poles, and trees, but you did not mention if there were any fine wires to the poles or other small wires in the area that you may not have seen. A common crash is drone hitting wires whether they be phone, electric, or otherwise. I have prechecked areas prior to flights and sometimes there are very thin wires that you cannot see unless your right up under them. A suggestion would be to go back and look to see if there are any you might have missed where you found your drone. If so, you may have your answer.

No wires at all. All the wires in that particular part of the park are underground. I do always stay well away from wires, of any kind. I often fly over the train lines but keep well away from the over power wires, for example.

I have been there several times, I love walking in that park. Here is another active track done that day. You can see that aside from the train tracks that are surrounded by wires and fencing, etc., which I kept well away from, there are barely any other wires around the park. I was playing around with Spotlight and then Active Tracking, but at about 30m high and then lower, at about 3m. It avoided the light posts very well.

aeciolemos · Dec 17, 2023

slup said:
Yeah, that's the same spot I show through CsvView... at 1256.9sec into the flight. And it's not conclusive that the tree had anything to do with the incident, not impossible (a very long branch low down hanging over that foot path?) but the drone seems to be clearing the tree (especially if you look at the GE 3D view. Would be good if the OP could shed some light around those light poles he mentions.

Tell me how to share that and I will

I am not sure into what it crashed. I would think if it were a twig, it would just stop and drop or something, but there was quite some damage, so I think it might have colided with a light pole.

Meta4 · Dec 17, 2023

aeciolemos said:
I am not sure into what it crashed. I would think if it were a twig, it would just stop and drop or something, but there was quite some damage, so I think it might have colided with a light pole.

The fall from 15 feet is sufficient to explain the damage.

aeciolemos · Dec 17, 2023

slup said:
It's not conclusive if looking into the data & exactly where the major attitude changes happens & where the messages about Blocked motor & Not enough force comes in...

In below chart I've placed the chart marker as close to 1256,9sec I could... it's there the blocked motor comes. It's also from there the major attitude changes starts. From there on we also have a Not enough force message lasting until the log ends.

If looking at where the drone is when all happens on the 2D sat map (all 3 windows below is synced) it look like the drone already have passed those suspicious trees. If we then also look at the 3D generated picture (further below) of the flight path in Google Earth it's likely that a 2D picture can trick us to believe that the trees was closer than they were in reality.

It's a mystery what the drone collided with if nothing obvious exists where all starts... the OP is the only one that can draw more precise conclusions here I believe. He have so far not described where those mentioned light poles where located...

(click on the pic below to make it larger, then click again to make it even larger... there the small text from the message stream window should be readable )
View attachment 171081

View attachment 171082

Sorry @slup I had not seen your message and analysis. That is brilliant how you plotted that. As you can see, I set the drone way to my back left so that it would be nowhere near the trees. The only part where the trees overhang the path is right in the begining, and I flew past those just in case.

The light poles are in that area to the left of the path (well, to the right in your picture above, opposite side of the trees). They are in a straight line, I would say some 10m apart. They are white, which should contrast well with the black/dark background of the trees. I will be in the area again some time this week and I'll take some pictures.

I honestly don't know what it crashed in to. I just heard the noise of it falling to the floor and looked back.

aeciolemos · Dec 17, 2023

mobilehomer said:
If you watch the playback on Airdata, the instant the blocked motor warning pops up, the drone is at the tree.

It is surely possible. Again, I "told" the drone to follow me to my back left, so it should not have been anywhere near those trees. If it did hit a tree, I have no idea why it was there. Also, it fell to the left of the path, opposite side to the trees when I found it. It was not under the trees.