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Mavic Air 2 Crash, shot backwards, uncontrollable

Jason89

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Hello, was flying my Mavic Air 2 around the beach today. It was working fine for a while. I went to do a quick shot and before it completed it stopped, it said altitude limit was reached. I went to fly it back down to try again and noticed it was getting hard to control. I was holding forward on the control stick and it would not go forward, it was just staying put. I let go of the forward control and the drone instantly shot backward at full speed before crashing into a hill. I attempted flight at home and same thing, it lifted then instantly shot backwards. I replaced all propellers and wiped off all sensors. It now will lift and go to the side as soon it starts up, it says propellor installation error now. I checked and they are all installed correctly, I put brand new ones on each. Any help would be appreciated. Only had the drone a couple months and have flown it probably 15 times. Worked flawlessly every time before today.

Here is the flight log where it crashed, I noticed toward the end the altitude is reading in the negative for some reason. It was probably 10-12 feet when it shot backward and crashed. DJI Flight Log Viewer - PhantomHelp.com

I attached the txt files for the log linked above and a couple flights I tried after getting home with the problems above.
 

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  • DJIFlightRecord_2020-06-30_[18-08-29].txt
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I let go of the forward control and the drone instantly shot backward at full speed before crashing into a hill.
Your flight data shows the drone flying fast backwards at the end of the flight, but it also shows you being in Sport Mode and pulling the right stick back from 6:05 including full back from 6:08.6 to the end of data at 6:12.2.
The data suggests that the drone was just following your joystick input.
 
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Your flight data shows the drone flying fast backwards at the end of the flight, but it also shows you being in Sport Mode and pulling the right stick back from 6:05 including full back from 6:08.6 to the end of data at 6:12.2.
The data suggests that the drone was just following your joystick input.
Could this be an uncommanded signal from the RC (E.g. faulty stick)? How could the OP check for this?
 
The aircraft behaved as commanded, and the rapid backwards flight at the end was due to a switch to sport mode and full back elevator:

combo1.png

That looks pretty conclusive, but the second log from your subsequent test suggests that there may be problems with the elevator stick output:

sticks2.png

That's almost certainly not normal, and is consistent with spurious rear elevator input.

Firstly, I would check the stick calibration. And are you using or wearing anything magnetic near the controller?
 
The aircraft behaved as commanded, and the rapid backwards flight at the end was due to a switch to sport mode and full back elevator:

View attachment 106496

That looks pretty conclusive, but the second log from your subsequent test suggests that there may be problems with the elevator stick output:

View attachment 106498

That's almost certainly not normal, and is consistent with spurious rear elevator input.

Firstly, I would check the stick calibration. And are you using or wearing anything magnetic near the controller?

I did RC callibration this morning and it seemed fine at first, but after moving the right stick around a bit it started registering a 100% leftward input even when the stick was in neutral position. Pressing it all the way right would decrease the left dirction by 15-20÷, but as soon as I let it go back to neutral it would continue reading 100% left. This probably explains what happened during flight. Wonder why this would happen though. I was not wearing anything magnetic when it occured.
 
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I did RC callibration this morning and it seemed fine at first, but after moving the right stick around a bit it started registering a 100% leftward input even when the stick was in neutral position. Pressing it all the way right would decrease the left dirction by 15-20÷, but as soon as I let it go back to neutral it would continue reading 100% left. This probably explains what happened during flight. Wonder why this would happen though.

If you didn't have any magnetic objects interfering then that's a faulty stick module.
 
If you didn't have any magnetic objects interfering then that's a faulty stick module.

Thanks for the help, guess I'll be emailing DJI, good thing I got DJI Care I guess. I just wonder what would cause this on such a new unit, I've only had it a couple months and I've never dropped it, always goes right back in case ect.
 
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If you didn't have any magnetic objects interfering then that's a faulty stick module.
Once he noticed the drone was not responding properly to commands, would the RTH function have done it's job?

I'm assuming yes, because of the lack of stick inputs, but there's always that quirky line of code somewhere.
 
Once he noticed the drone was not responding properly to commands, would the RTH function have done it's job?

I'm assuming yes, because of the lack of stick inputs, but there's always that quirky line of code somewhere.

Switching off the RC would probably have worked, but while the RC was connected the spurious elevator input was going to be a problem in any mode.
 
Switching off the RC would probably have worked, but while the RC was connected the spurious elevator input was going to be a problem in any mode.
I have yet to see (stupidly I'll admit) what happens when I have a phone or RC disconnect. ?‍♂️


I'm going to test that soon though
 
I have yet to see (stupidly I'll admit) what happens when I have a phone or RC disconnect. ?‍♂️


I'm going to test that soon though

A phone disconnect doesn't cause any specific behavior. An RC disconnect (from the aircraft) triggers failsafe behavior.
 
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Thanks for the help, guess I'll be emailing DJI, good thing I got DJI Care I guess. I just wonder what would cause this on such a new unit, I've only had it a couple months and I've never dropped it, always goes right back in case ect.

What benefit would DJI Care offer, if this issue is covered under warranty?
 
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I have yet to see (stupidly I'll admit) what happens when I have a phone or RC disconnect. ?‍♂️


I'm going to test that soon though

I've had my Mini and Air 2 lose connection and as designed they both began RTH until I regained signal, cancelled RTH and resumed flying manually. Odd that I've never had a disconnect with either of my Mavic Pro or Platinum in similar distances and conditions (always have line of sight between RC and aircraft).
 
What benefit would DJI Care offer, if this issue is covered under warranty?
Good point, the RC should be warrantied for 12 months and you would think any damage to aircraft that resulted from the crash due to faulty RC input would be covered also. So I guess I didn't need it for this scenario, although I thought I remembered reading with DJI Care you get express service or something? Maybe I am remembering that wrong.
 
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