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Mavic 2 pro crash, help needed

Civics69

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Hi Guys, I hope someone on here can help me out. While flying this morning, my drone appeared to start acting a bit strange.
At approx 8.10 in the flight log, the drone started doing things without my input. This resulted in the drone crashing into a very soft bush on the top of a cliff, luckily sustaining no damage.
I take full responsibility for the actual crash as it was my input that put it there, not intentionally, i was just trying to regain control.
I have never experienced anything like this with the drone and flew at the location many times.
When I retrieved the drone, everything seemed fine, no battery hanging out or damage to the props etc. I then tool it to an open field to check it out and it flew perfect with no more issues. Launched, hovered, responded to control inputs perfectly, landed etc.

Hope someone can help as i am at a total loss.
 

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sar104

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Things went badly wrong at around 494 seconds when the aircraft was yawed CW through north - the first time that it had pointed north during that flight.

Delta_V.png

It suggests a compass issue, but this one needs the DAT file (FLY071.DAT) to explore further.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet
 

Civics69

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Things went badly wrong at around 494 seconds when the aircraft was yawed CW through north - the first time that it had pointed north during that flight.

View attachment 82086

It suggests a compass issue, but this one needs the DAT file (FLY071.DAT) to explore further.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet
Hi Sar104, thank you for your quick response. Just to update you on more info, i had already flew for around an hour with other batteries with no issues, if that helps.
I tried to upload the .DAT file but it says its to large. (12mb)
 

sar104

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Was able to ZIP the file, really hope this helps.
Thank you again for taking the time to review.
IMU1, which appears to have been active, had significant issues starting at 494 seconds - specifically recording yaw excursions (green dashed trace) that were not real:

yaw.png

yaw_error.png

Neither of the rate gyros nor the compass saw those excursions, so I cannot explain which data IMU1 used to compute them.
 

MaxHam

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I'm wondering if it may have something to do with the frequent N/A for VPS altitude. (@ Civics: I wouldn't turn downward positioning on low over water)

Someone here, maybe sar104, will know:
If VPS altitude readings are mostly unavailable or jump: Does the system ignore this and rely on the barometer or can this result in a crash?

1.jpg
 
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Civics69

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I'm wondering if it may have something to do with the frequent N/A for VPS altitude. (@ Civics: I wouldn't turn downward positioning on low over water)

Someone here, maybe sar104, will know:
If VPS altitude readings are mostly unavailable: Does the system ignore this and rely on the barometer or can this result in a crash?

View attachment 82114
Upon review I am sure the drone was more than 4-5 ft high at that point. It initially launched at sea level (on the beach). I have heard that also with regards to downward positioning etc, but never had any issues in the past as most of my flying takes me over the sea. The drone flew flawlessly on the field shortly after, as I wanted to make sure everything was ok. Nervous now though.
 

sar104

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I'm wondering if it may have something to do with the frequent N/A for VPS altitude. (@ Civics: I wouldn't turn downward positioning on low over water)

Someone here, maybe sar104, will know:
If VPS altitude readings are mostly unavailable or jump: Does the system ignore this and rely on the barometer or can this result in a crash?

View attachment 82114
VPS height measurement drops out above 7 or 8 meters, but it looks to me as if there is some kind of issue with the log file conversion. The VPS height, compared with barometric height, looks like this:

height.png
 

Civics69

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VPS height measurement drops out above 7 or 8 meters, but it looks to me as if there is some kind of issue with the log file conversion. The VPS height, compared with barometric height, looks like this:

View attachment 82125
I can definitely confirm it was a lot higher than the log implies. What do you suggest I do going forward. Really don't like the idea that something as heavy as this drone drops out of the sky and of course the cost etc.
Really do appreciate all your help guys.
 

sar104

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I can definitely confirm it was a lot higher than the log implies. What do you suggest I do going forward. Really don't like the idea that something as heavy as this drone drops out of the sky and of course the cost etc.
Really do appreciate all your help guys.
Are you sure? The flight elevation profile looks about right to me:

1569098332006.jpeg
 
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Civics69

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Where the log shows 4-5 ft I was definitely higher because I was staying above the ground photographers, making sure I wasn't in their shots.
What would you guys suggest I do. Really don't fancy flying it again, could have been so much worse. Still find it hard to believe the number of times I read about such issues regarding these drones. Having a mind of there own, dropping out of the sky etc. These things have the potential to cause serious harm.
Appreciate all your help guys.
 

sar104

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What would you guys suggest I do. Really don't fancy flying it again, could have been so much worse. Still find it hard to believe the number of times I read about such issues regarding these drones. Having a mind of there own, dropping out of the sky etc. These things have the potential to cause serious harm.
Appreciate all your help guys.
At this stage I'm not really sure what to suggest. There have been a few reports of somewhat similar events recently, and the cause is not clear. Perhaps install the new firmware update and run a couple of controlled test flights:

Power up the aircraft on the ground and don't move it before takeoff. Check that the aircraft orientation arrow in the app agrees with the direction that the aircraft is facing. Takeoff and climb to 10 meters or so and then do a couple of full CW and CCW rotations. Then post the DAT file back here.
 

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Lonjsnyder

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I prefer changing one of the mode switches to enable ATTI mode in case of any unexpected flight behavior.

 

Joe4flight

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All, I’ve been flying a MPP for about a year now. I’ve read though every post here and am extremely impressed with everyone’s technical knowledge. I’ve never considered any of this stuff when going on my own very careful and mostly uneventful flights. I’m really missing a level of technical understanding here. How did you all get so knowledgeable about this? How do you suggest I do? Are there drone flight classes I can sign up for somewhere? Thx!!
 

Civics69

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Thanks guys for all your feedback. I have installed the new firmware, will perform a full calibration of everything, do the test flight and submit logs etc. ATTI mode sounds like s good idea, would have definitely saved my climbing up the cliffs 😀