Lost my Mavic drone with 20% battery left.

[vishusethu]

Hey all, I lost my Mavic Pro 1 when flying in low temp conditions. I was flying back to home location when the RTH got triggered and suddenly lost connection with a auto landing warning. I guessed the batteries died due to cold. Looked everywhere at the last location but couldn't find it. Any insight is appreciated.

Flight logs: DJI Flight Log Viewer - PhantomHelp.com

@Meta4 @Yorkshire_Pud Could you please help?

 

[msinger]

Since your drone was landing at the last recorded point in the flight log, it should be easy to track it down. Go to the last recorded location (37.69872918, -118.7621309) and then walk the pink line below until you find it. It shouldn't be far from that last recorded location.

 

[vishusethu]

Thank you! I did look around that area but couldn't spot it. There's a ton of snow in that area, upto chest level when walking. So my thinking was it got buried in. But couldn't find any noticable holes either.

 

[msinger]

There's a ton of snow in that area, upto chest level when walking

That's unfortunate. You might have to return after the snow melts since there is no way to pinpoint the exact location.

Since it was landing (and not falling from the sky), it could be sitting on top of the snow somewhere. I guess it depends on how soft and deep the snow was at the landing location.

 

[vishusethu]

Thanks a lot, I hope so. I wish to atleast retrieve my card back.

 

[MAvic_South_Oz]

Since your drone was landing at the last recorded point in the flight log, it should be easy to track it down. Go to the last recorded location (37.69872918, -118.7621309) and then walk this pink line until you find it:

But the battery had probably died at the end of log point.
The cells were all over the place, whether from massive fail or cold, or a combination of those . . . I wouldn't be surprised it it just plummeted at that point.
If so, wind speed would need to be calculated for altitude at that point (111'), and project an approx distance it might have covered in the wind direction.

There's a ton of snow in that area, upto chest level when walking. So my thinking was it got buried in.

Oh yeah, it would have made a 'snow angel' and likely with the M1P colour and heat present from flight, it would sink n pretty well.

 

[msinger]

Oh yeah, it would have made a 'snow angel' and likely with the M1P colour and heat present from flight, it would sink n pretty well.

Ah, and that's a good point too. Even if it did manage to safely land, it could have melted the snow beneath it.

 

[vishusethu]

But the battery had probably died at the end of log point.
The cells were all over the place, whether from massive fail or cold, or a combination of those . . . I wouldn't be surprised it it just plummeted at that point.
If so, wind speed would need to be calculated for altitude at that point (111'), and project an approx distance it might have covered in the wind direction.



Oh yeah, it would have made a 'snow angel' and likely with the M1P colour and heat present from flight, it would sink n pretty well.

Yes you're right, my gut feeling says it just plummeted down because the temps was around -14°C well below the rated the -10°C (that I know now )

There was no noticable wind atleast at the surface, but I'm not sure at 111'. I don't think any service provides historical wind speeds so I'm out of luck there.

I will attempt to look again after the melt, which is the only option now, because more snow is on the forecast.

Thank you for the your insight.

 

[MAvic_South_Oz]

There was no noticable wind atleast at the surface, but I'm not sure at 111'. I don't think any service provides historical wind speeds so I'm out of luck there.

Maybe a better flight analysis person can recap your log, advise if they can see the battery giving out ion flight at logs end . . . an Air Data report has wind info, but at a mere 100' or so, it probably wasn't too much different to what you sensed on the ground, possible, but unlikely.

Possibly you know someone with a metal detector and can go walk a grid in the snow if it's not too deep or difficult to walk ?

 

[Yorkshire_Pud]

The only thing I could add to what has been said is, that if it did free fall then I'd suspect it had only 2 to 3 seconds before it hit the snow, so maybe travel 64 - 96ft (assumes no significant speed drop off 22mph =32ft/s) from the loss of signal point along Msinger's pink line.
I CSC'ed a P3 and it took around 2.5sec to fall the first 33m but it was descending prior to the motor start so it did have a bit of a head start.
It would hit quite fast so probably dug a hole.

Airdata (freebie version) says the wind was 10.4mph from 331deg i.e. more or less a tailwind.

If it didn't stop the motors then the descent speed at the end of the log was 8.5ft/s and the manual says the max descent speed is 9.8ft/s, from 111ft those give 11.3sec to 13 sec + a few sec for the final slow descent but shouldn't have drifted far as the GPS was good.
I don't know if it would or could reject the landing site in these circumstances but if it did, during a hover at low battery it might have been unable to fight the wind and drifted down wind until the battery gave out.

 

[Yaros]

The crash happened because the cell 3 of your battery went very low. Although the percentage was around 20%, the cell voltage in cell 3 was way below the threshold of 3.0V. Then when the voltage of that cell went below 2.0V the drone couldn't hold anymore and disconnected.

This could have happened for a few reasons:
- Your battery wasn't recently charged and was on auto-discharge already
- You flew too aggressively without heating the battery previously by flying slowly
- The state of your battery already was bad before this flight