Help analyzing crash / flight data

[toddobannon]

Problem? Soft crash in snow

Was unit in a crash? slow controlled "crash".

What have you tried so far?: nothing

What device are you using? iphone x

What firmware are you running ( aircraft, remote controller)? newest

What Go app version are you using? newest version

Any modification? its all a stock unit

Did you change anything or install any apps? no

Do you have a video or pictures of the problem? Attached pictures of the landing

I took off from blacktop and elevated about 6 feet. I then moved over the snow covered field and started to go up and forward a little bit. This was when it went weird. It started to veer off to the left and didn't seem to respond. I put both joysticks down to bring the unit down before it took off. It did crash/land backwards which supports my recollection of the downward right control.

I honestly don't know if I did anything wrong. I am assuming the snow had something to do with it. I have never had this issue before. I've flown quite a bit and this just seemed to be too uncontrolled. Again, wondering if the snow had anything to do with the sensors?

Hoping someone will be able to read the log and see what happened. If it was op error, just need to understand that to watch out for that again.

TYIA

 

[Meta4]

This was when it went weird. It started to veer off to the left and didn't seem to respond.

Here's what your flight data looks like.
DJI Flight Log Viewer - PhantomHelp.com
You gave it some pretty extreme joystick input.
I can't see any movements that don't match your joystick inputs or anywhere where it looks weird.

 

[GregD]

I hope there was no damage.
I agree with @Meta4. Everything looked good.
I am confused as to why you pulled the right stick when you were trying to land. Pulling both right and left sticks down is not the way to land or shutoff the motors in an emergency (take a look at the User Manual page 50).

I also do not think snow on the ground was a factor. Take a look at some of the videos on youtube where DJI drones are flown in extreme weather. Checkout 51Dones, he is in North Dakota and flies in the winter.

Good luck in your future flights.

 

[toddobannon]

No damage. It was a very soft landing. Thank you both for your input and I appreciate Meta4 pulling the data.

You notice how the heading of the MA is headed south and it was moving to the north. That was the weird part that I failed to mention. I don’t think the joystick controls are showing any sort of movement other than backwards and down. I don’t know why the unit was facing south. I guess since the right joystick down, It makes sense that it was going backwards. But I still don’t understand how it turned to the south.

 

[Meta4]

I don’t think the joystick controls are showing any sort of movement other than backwards and down.

As well as pulling the sticks backward, there was sideways input.
From 0:19.6 to 24.8 there was rudder input that rotated the drone and from 0:18.7 to 0:25.8 the right stick was pulled off to the side causing sideways movement.

 

[toddobannon]

Thank you. I appreciate the help. I think this is solved. Much thanks.

 

[sar104]

I don't think it was responding properly. If you compare elevator/pitch and aileron/roll they do not correspond at all well:





Rudder and throttle response looked fine. What were the weather conditions?

 

[toddobannon]

It was a little windy. 7-10 mph from the west. Gusts around that time to ~15. But at that time of take off it wasn’t bad. I’ve flown in worse and been compelled to RTH before I even got high wind warnings. This wasn’t bad.

 

[sar104]

No damage. It was a very soft landing. Thank you both for your input and I appreciate Meta4 pulling the data.

You notice how the heading of the MA is headed south and it was moving to the north. That was the weird part that I failed to mention. I don’t think the joystick controls are showing any sort of movement other than backwards and down. I don’t know why the unit was facing south. I guess since the right joystick down, It makes sense that it was going backwards. But I still don’t understand how it turned to the south.

You launched facing east. The aircraft ended up turning to the south because you applied right rudder:



The aircraft was then moving backwards due to the positive pitch that you can see in the first graph in post #7.

It looks to me, from the sparse data, that there was a significant gust wind from out of the SW, and the aircraft was initially pitching back and rolling right to combat it while heading east. After you turned the aircraft to the south and manually applied backwards pitch with the elevator it then headed north. I'm not sure why the pitch did not increase beyond around 15° when you applied full backwards elevator, but that's the only obvious oddity with the flight data given the conditions.

 

[GregD]

Oh man, I tried to put too much on the chart in CSvView and got confused. Thanks @sar104 for your analysis and explanations.

 

[BudWalker]

Oh man, I tried to put too much on the chart in CSvView and got confused. Thanks @sar104 for your analysis and explanations.

You can always use multiple SigPlayers (charts). They are time synchronized. I.e moving the value tracker in one SigPlayer will cause the value tracker to move in all the other SigPlayers.

 

[GregD]

You can always use multiple SigPlayers (charts). They are time synchronized. I.e moving the value tracker in one SigPlayer will cause the value tracker to move in all the other SigPlayers.

Thanks. I will give that a try and see how it goes. I hope all is well with you. I do have a question about the axis ranges in CSVView. Can they be edited? For instance, if the right axis places zero at the top of the scale can the range be changed to bring the wave down in the chart?

 

[BudWalker]

Thanks. I will give that a try and see how it goes. I hope all is well with you. I do have a question about the axis ranges in CSVView. Can they be edited? For instance, if the right axis places zero at the top of the scale can the range be changed to bring the wave down in the chart?

No, it's pretty much automatic. For things like you need a real plot package. Like Igor Pro that @sar104 uses.

 

[GregD]

No, it's pretty much automatic. For things like you need a real plot package. Like Igor Pro that @sar104 uses.

Thanks, I didn't think you could adjust them, just thought I would ask. Actually, I am learning Igor Pro and @sar104 has been very helpful.