DJI Mavic 2 Crash - Flight Log - Help Interpret - Cell Deviation?

[gershee]

I think I'm going crazy.
I'm fly a DJI Mavic 2 Zoom, latest firmware, DJI Go (Android, latest).
I was flying indoors, carefully, doing a photo shoot, in TRIPOD mode, and all of a sudden the drone took off on me and flew into the wall.
I do NOT believe I flew into the wall.
Here is the flight log.
https://drive.google.com/open?id ... h9QowHqQkH7d7OUEVMo

When I uploaded the flight log of the crash to a Log viewer (phantomhelp.com) it comes up red at the time of the crash and says "Cell Deviation".
Is something wrong with my battery?
This is the third time the drone has taken off into a wall.
Can someone help me interpret the crash log?

 

[Meta4]

I was flying indoors, carefully, doing a photo shoot, in TRIPOD mode, and all of a sudden the drone took off on me and flew into the wall.

If you were relying on GPS for position holding, you were out of luck.
You didn't have any GPS at all for the whole flight (GPS Level was zero)
That meant the drone had no horizontal position holding and no brakes and would keep drifting when you went hands off on the controls.

When I uploaded the flight log of the crash to a Log viewer (phantomhelp.com) it comes up red at the time of the crash and says "Cell Deviation".
Is something wrong with my battery?

Probably not.
It's normal for there to be small differences in the cell voltages.
0.15 volts is not a big difference in cell voltage.
It certainly had no effect on the crash.

 

[Simmo]

Can you upload your .DAT file?

How to retrieve a V3.DAT from the tablet

 

[kilomikebravo]

ou didn't have any GPS at all for the whole flight (GPS Level was zero)

Meta: Is that a record? First time I remember hearing zero on an incident report.

 

[gershee]

Can you upload your .DAT file?

How to retrieve a V3.DAT from the tablet

For some reason the .dat files seems to stop the day before the crash.

This is the last dat file I found but the date says a day before the crash.

19-05-28-03-08-19_FLY027.DAT

drive.google.com

 

[Meta4]

Meta: Is that a record? First time I remember hearing zero on an incident report.

Here's what the data looks like: DJI Flight Log Viewer - PhantomHelp.com
I don't know about a record but although there were generally low numbers of satellites showing the GPS Level (flight controller's confidence in the GPS accuracy) was 0/5 for all 1200 records - except for the last 3 seconds when it went up to 1/5 and a single record (4/5) at 2:00.7.

 

[sar104]

If you were relying on GPS for position holding, you were out of luck.
You didn't have any GPS at all for the whole flight (GPS Level was zero)
That meant the drone had no horizontal position holding and no brakes and would keep drifting when you went hands off on the controls.

Probably not.
It's normal for there to be small differences in the cell voltages.
0.15 volts is not a big difference in cell voltage.
It certainly had no effect on the crash.

The problem here was the usual one flying indoors. While the aircraft was using VPS, which was for most of the flight, it was stable. However, at 114.5 it switched to using GPS, even though it had a poor navHealth (2). That led to all the flight problems:

 

[gershee]

The problem here was the usual one flying indoors. While the aircraft was using VPS, which was for most of the flight, it was stable. However, at 114.5 it switched to using GPS, even though it had a poor navHealth (2). That led to all the flight problems:

View attachment 74106

YES. So does this confirm it could have moved on it's own?
Maybe while it was flying VPS it wads fine and then once it switched to GPS it moved or veered and then hit the wall?
I was hovering at about 10-12ft about 4-5ft from a wall.
Out of no where the drone takes off towards the wall high speed and I did not have time to correct.

 

[sar104]

YES. So does this confirm it could have moved on it's own?
Maybe while it was flying VPS it wads fine and then once it switched to GPS it moved or veered and then hit the wall?
I was hovering at about 10-12ft about 4-5ft from a wall.
Out of no where the drone takes off towards the wall high speed and I did not have time to correct.

Yes - that's almost certainly what happened, and is the big hazard of flying indoors, especially in such a confined space.

 

[gershee]

Yes - that's almost certainly what happened, and is the big hazard of flying indoors, especially in such a confined space.

How can I avoid this in the future?
Would this be covered by warranty as there is visible damage to one of the front arms?
Thanks to everyone for the info.

 

[sar104]

How can I avoid this in the future?
Would this be covered by warranty as there is visible damage to one of the front arms?
Thanks to everyone for the info.

Don't fly indoors - these aircraft are not designed to do that.

And no - it's very unlikely to be covered by warranty.

 

[gershee]

Don't fly indoors - these aircraft are not designed to do that.

And no - it's very unlikely to be covered by warranty.

I didn't not realize they aren't able to fly indoors properly.
It was a huge warehouse and it seemed safe enough until the drone took off straight into the wall.
Thanks for your help.

 

[sar104]

I didn't not realize they aren't able to fly indoors properly.
It was a huge warehouse and it seemed safe enough until the drone took off straight into the wall.
Thanks for your help.

That's not my idea of a huge warehouse. In flying terms - that's a confined space.

 

[paulatkin73]

I didn't not realize they aren't able to fly indoors properly.
It was a huge warehouse and it seemed safe enough until the drone took off straight into the wall.
Thanks for your help.

you need to alter one of drone modes into the ATTI mode that will not use GPS - that should prevent any occasional darts into walls and obstacles. ATTI will not use optical sensors, which is a pity, but, it is still safe.
we had that conversation earlier here, and, unfortunately, DJI did not implement any way to lock and use optical avoidance system alone with no GPS inputs. that would be ideal for indoors, but, it is not possible. ATTI mode is possible and is relatively safe.

 

[Mav1c]

Can’t you just turn off RTH and other sensors of the like? Not saying that I would personally choose to fly inside but I think turning off those things will prevent it from friggin off into the wall/ceiling. Either that or reconfigure tripod mode into opti mode if possible?

 

[paulatkin73]

Can’t you just turn off RTH and other sensors of the like? Not saying that I would personally choose to fly inside but I think turning off those things will prevent it from friggin off into the wall/ceiling. Either that or reconfigure tripod mode into opti mode if possible?

not possible.
darting is the symptom when the drone`s gps starts glitching and drone thinks its position changes (while been in fact stationary), so, it tries to compensate and moves around erratically. it is well known, same may happen if you fly outside and get into, say, a gazebo that partially blocks the sky, so you suddenly will lose bunch of satellites and may also get erratic movement.

when all gps is gone drone will switch into opti mode, but the issue happens prior to that, when gps is not completely gone, but only partially and it produces bogus position data. and, unfortunately, there is no such mode where gps is simply disable while all optical paths are enabled. why - because it is dji and a closed platform, nothing can be done there until somebody writes a freeware code for this platform, that is highly unlikely to happen.

 

[Mav1c]

not possible.
darting is the symptom when the drone`s gps starts glitching and drone thinks its position changes (while been in fact stationary), so, it tries to compensate and moves around erratically. it is well known, same may happen if you fly outside and get into, say, a gazebo that partially blocks the sky, so you suddenly will lose bunch of satellites and may also get erratic movement.

when all gps is gone drone will switch into opti mode, but the issue happens prior to that, when gps is not completely gone, but only partially and it produces bogus position data.

Ok, that makes sense. I see why atti would be the only way around that but it would make for quite the challenge and not much room for error. You wouldn't have the deal with the wind but even the prop wash moving around the room would make it drift a little. Too risky

I feel like if you're trying to film inside you could always just hold and walk with the drone and get pretty good results.

 

[jbuy41]

Today I crashed into the side of a water tower. I looked at the playback on dji go4 and it shows flying above at 96 ft., above the water tower, so is the altitude wrong on my app? Shouldn't OA prevent this from happening?
Been licensed for over 3years and fly when weather permits. Over 100miles and 27 hours. But i need help reading my data downloaded from my ipad pro to see what was going on.

 

[Shon]

Today I crashed into the side of a water tower. I looked at the playback on dji go4 and it shows flying above at 96 ft., above the water tower, so is the altitude wrong on my app? Shouldn't OA prevent this from happening?
Been licensed for over 3years and fly when weather permits. Over 100miles and 27 hours. But i need help reading my data downloaded from my ipad pro to see what was going on.

I'm confused by your statement... Isn't the altitude shown on the screen relative to the take-off point, and not the water tower? What did the view look like from the drone's POV?

I can tell you from my own experience... I've almost crashed into a tower...from the ground...it looked like I had plenty of clearance 50 feet or so...altitude showed I was about 20 feet above the highest point of the tower (Probably my take-off/landing area was slightly lower than where the tower was measured)...the video itself looks like I missed it by inches (38 second mark in video):

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[Meta4]

i need help reading my data downloaded from my ipad pro to see what was going on.

Help is available ...
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report of the flight.
Come back and post a link to the report it gives you.