P3P crash root cause speed error?

[porrascarlos80]

team, It was a nice place to fly no wind observed .

Suddenly It went into Atti mode and crashed. shouldn't it be kept hovering and moving forward to his desired way??

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Could a problem with one of the propellers be called speed error?

 

[RodPad]

Welcome to the Forum!

Sorry for the crash, I been there and to many times. Don't listen to me.

From memory, as a soon as I spotted speed error, I was looking for a compass message, yep its there.

Basically the compass and GPS have conflicts, so the Phantom goes in to ATTI.
ATTI, is going to let it drift with the wind, it will not hover.

I guess it doesn't trust the compass or the GPS. So on that thought, why don't they use the GPS only?
Let you make the decide what to do, you can always switch to ATTI if you want.

Anyways...

I'm sure you will get much better answers soon.

@sar104, @Fly Dawg, @Meta4.
Any you guys working this Holiday?


Rod

 

[RodPad]

Hum, "Could a problem with one of the propellers be called speed error? "

Elevation comes from the Barometer, the speed error, compass error and then elevation starts falling fast. What's you thought on the Props?


Rod

Added: with my limited knowledge, Prop, Motor or a Bird strike?
That's all I got.....

 

[porrascarlos80]

Something more to add , on 09 01 2019 the drone when flying over a lake , suddenly said, ATTI mode and flew away. I elevated it more and selected , return to home and landed it manually because came back over trees. Same props.

I was using carbon fiber props, one of them when mounted made the motor sound like very little grinding , motor alone wont emit that insignificant noise. But drone was flying fine on first video.

Drone flew fine for first video , I will upload it and suddenly one more ATTI mode alert, people creamed observing my DJI P3P going in freefall. No trees around at 55M altitude.

Drone was found with camera upside and battery apart. I will take pictures and post details, unfortunately the falling was not recorded .

 

[Meta4]

team, It was a nice place to fly no wind observed .

Suddenly It went into Atti mode and crashed. shouldn't it be kept hovering and moving forward to his desired way??

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Could a problem with one of the propellers be called speed error?

Before the error messages show up, the drone was flying forward in a northerly direction.
The joysticks were released at 3:56.2 and the drone slowed down
At 3:57.2 we see the drone starts to rotate, the drone pitches and rolls.
At the same time the drone rapidly loses height and tumbles toward the ground.
At 3:57.9 the Speed Error messages start to show.
These are a symptom of the failure rather than pointing to the cause.
The flight controller reacting to the information it's receiving from the sensors as the drone tumbles.
It lost GPS when the drone rolled/tumbled and that was the reason it went into atti mode.
The compass error is because the drone is spinning.

Were all props intact and attached?

 

[porrascarlos80]

great analysis, yes, props were in place.

So how to identify what caused this to avoid repairing it and suffering the same damage or worse:
"At 3:57.2 we see the drone starts to rotate, the drone pitches and rolls.
At the same time the drone rapidly loses height and tumbles toward the ground. "

 

[Meta4]

great analysis, yes, props were in place.

So how to identify what caused this to avoid repairing it and suffering the same damage or worse:
"At 3:57.2 we see the drone starts to rotate, the drone pitches and rolls.
At the same time the drone rapidly loses height and tumbles toward the ground. "

@sar104 might be able to dig a little deeper to see if there's any indication of what caused the problem.

 

[porrascarlos80]

one more speed error observed on day 08 31 2019 when I triggered RTH :

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[Fly Dawg]

one more speed error observed on day 08 31 2019 when I triggered RTH :

The speed error is unrelated to the incident. Those occured during the tumble. That is related to the IMU positioning and Velocity Calculations. It certainly looks like a lost prop as you released the elevator.

 

[Capt KO]

Don’t know how much damage you have, but I suspect a motor failure. If you can remember which motor made the noise with the prop attached, remove props off of all motors, with one finger spin the motors as fast as you can. I think you’ll find one motor is louder than the others or not working at all. Just an opinion, but It’s worth a quick look. Been there. If not, keep looking. Best of luck.

 

[cheddarman]

I was using carbon fiber props, one of them when mounted made the motor sound like very little grinding , motor alone wont emit that insignificant noise. But drone was flying fine on first video.

Just reading this would make me suspect a prop/motor/ESC failure and FlyDawg confirms this with his amazing analysis of the data logs. If I heard anything out of normal I would not fly until I had thoroughly checked out everything.

 

[porrascarlos80]

Actually I did a test fly prior to this event to ensure if the aircraft fails then will be near to me , less distance to walk to pick parts but passed, then flew away , I wanted to shoot a nice tree over the next mountain and then .... p3p hit ground. I will post pictures and video of previous fly by tomorrow.

 

[cheddarman]

The speed error is unrelated to the incident. Those occured during the tumble. That is related to the IMU positioning and Velocity Calculations. It certainly looks like a lost prop as you released the elevator.
View attachment 114201

Hey Fly Dawg, you know what I'm going to ask, how do you come to that conclusion from the above plots? Everything seems to be going everywhere, I don't se anything suddenly stopping.

 

[Fly Dawg]

how do you come to that conclusion from the above plots?

Gold Plot- Elevator: Goes to Zero Input gradually.
Red Plot- Aircraft Pitch : Pitches up as you would see in a fast stop, but much more severe.
Aqua Plot- Aircraft Roll : Sudden severe roll to the left.
Afterwards the tumble begins.
Is that what you were asking?

 

[Deleted member 120647]

If of use......
If you look in the dat file for the flight, you will need to down load it from the drone and then run it througha program like DatCon, I believe the actual motor speeds, as recorded by the drone, are columns 111 to 114 of the .csv output of "DatCon" when that .csv is opened as a spread sheet.
For me these particular columns have no titles unless I type one.

 

[Fly Dawg]

For me these particular columns have no titles unless I type one.

Then there is something wrong with your interface. The motor data is there in labelled columns. Assuming you configured it correctly. You can view the files graphically directly in CSV View. Unless you are looking specifically for a spreadsheet version, which does work as well.

 

[Deleted member 120647]

I have tried both spread sheet programs I have (open office and MS works) and, for me, there are no titles beyond column 108/DD in the output .csv of DatCon.
It may well be that my software is antiquated but with this exception MS works is all I need. At some point I may open the csv with notepad or similar and work out where the first line ends and see.....

 

[Fly Dawg]

t may well be that my software is antiquated but with this exception MS works is all I need. At some point I may open the csv with notepad or similar and work out where the first line ends and see.....

If you want graphical representations use this: CSV View

 

[Deleted member 120647]

"If you want graphical representations use this: CSV View " Ta.

 

[Fly Dawg]

If you want graphical representations use this: CSV View " Ta.

Ok, that made no sense whatsoever. Your Point?