Mavic air crash

[Jcastro1836]

@Jcastro1836 . . . from post #11, do this and there will be a proper look at the problem.

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[Jcastro1836]

Sorry guys believe I did it right now.

 

[MAvic_South_Oz]

Got it right now
Just looking at the obvious error messages, the cell deviation was here a long time, and quite a log way out at furthest point (where signal interuption errors happened).
I'd say you have a bad battery, but others can probably tell better.

You did turn at the 5m4s mark towards the forest, then slight turn to the left seemed to complete that (could be finger on stick just a little, calibration issue, or maybe wind ?).
Then it was full steam forward until well into that vegetated area.
Did you mean to fly this way, with probably battery errors and signal warnings ?

It then hit critical battery ?
Did the craft not try RTH before this ?
Or a low battery warning appear ?
(I skipped through lines pretty fast.)

Hope the analysts can make more sense from the info.

Hope you can get it sorted and either find it or get another Air to fly.

 

[Gryphon962]

Cell 3 on the battery lost more and more voltage until at one point it was over a volt below the other 2 cells. Thats way too low. The overall battery voltage fell until it was so low that it showed 0%, and, as this was below the percentage setting for forced landing, it went into forced landing mode, and descended in that mode until the flight ended.

What got my attention was that while in forced landing mode, with the drone still airborne and descending, Cell 3 came back, recovered a lot of the voltage it had lost, and the overall voltage recovered with it. However, the battery percent stayed at zero, so it kept doing its forced landing. Forward movement throughout the whole forced landing seems to be almost zero.

So what else could you have done at the time? I think I'm correct in saying that the drone will fly and respond to controls as long as it has 'enough' voltage, even if its reporting 0%, so it might have been possible to fly it home (with up throttle to override the forced landing mode). Unfortunately you didn't know the voltage had recovered, and as it was 1400 ft away, I doubt you would have been able to control it visually, with up throttle to stop it sinking, and then get it pointed in right direction and moving forward.

So in sum, I think you have a battery cell that failed. What could you have done to preclude that? Most of us upload all our flights, and check the online metrics for deviations among the cells - if over a few flights the deviation gets worse, replace the battery.

 

[sar104]

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That looks like a bad battery. The cell voltages drop precipitously when the current goes up:

 

[MAvic_South_Oz]

sar104, if I can ask you . . .

Does the log show any warnings about low battery (not just the critical battery), and more importantly was here a RTH triggered automatically when (if ?) the Air registered time to come home ?
Unless RTH was disabled.

Or was it simply the possible bad battery skipped through what would have normally registered an auto RTH ?

 

[sar104]

sar104, if I can ask you . . .

Does the log show any warnings about low battery (not just the critical battery), and more importantly was here a RTH triggered automatically when (if ?) the Air registered time to come home ?
Unless RTH was disabled.

Or was it simply the possible bad battery skipped through what would have normally registered an auto RTH ?

There were no battery warnings until 374 seconds, when the smart battery level went from 54% to zero and the aircraft switched to autolanding.

 

[MAvic_South_Oz]

There were no battery warnings until 374 seconds, when the smart battery level went from 54% to zero and the aircraft switched to autolanding.

Ah, the drop to 0% and auto landing kicked in same time, makes sense then that it did skip over warnings, as it wasn't registering for that procedure to occur up to that point.

So even though the battery seemed to have very poor health from early on (almost from the start of the flight), the 374 seconds mark was the nail in the coffin ?
Did these cell / battery warnings appear on the app do you think ?
Or the battery icon show anything to be watchful for ?

The OP probably had one choice here (besides taking note of various warnings, if they occurred / appeared on the Go4 app and ending flight asap).
Turn gimbal straight down, and try to find a place to guide it to auto land where recovery may have been possible.

 

[sar104]

Ah, the drop to 0% and auto landing kicked in same time, makes sense then that it did skip over warnings, as it wasn't registering for that procedure to occur up to that point.

So even though the battery seemed to have very poor health from early on (almost from the start of the flight), the 374 seconds mark was the nail in the coffin ?
Did these cell / battery warnings appear on the app do you think ?
Or the battery icon show anything to be watchful for ?

The OP probably had one choice here (besides taking note of various warnings, if they occurred / appeared on the Go4 app and ending flight asap).
Turn gimbal straight down, and try to find a place to guide it to auto land where recovery may have been possible.

If the DJI GO 4 app was set to display voltage, rather than just the SMART_BATTERY_battery percentage, then the problem would have been apparent earlier.

 

[sar104]

The OP probably had one choice here (besides taking note of various warnings, if they occurred / appeared on the Go4 app and ending flight asap).
Turn gimbal straight down, and try to find a place to guide it to auto land where recovery may have been possible.

There's not much doubt about where it ended up:

 

[MAvic_South_Oz]

Get the walking boots on, or maybe Wellingtons ?
Worth a go.

 

[RayOZ]

Seems like older batteries tend to get that way. My Spark’s voltage trend seems to have consistent minor deviations between cells when flying in P-Mode, like OP’s. I won’t be flying in Sport mode.

 

[Jcastro1836]

Appreciate you guys looking into this for me. Unfortunately I’ve tried to go back there as far as I could and it’s all covered in water from all angles. As for the battery I had no idea it was a bad battery hadn’t given me any issues before then. For future reference if I can afford to get another drone I know to check for Cell deviations frequently. And it all happened so fast when it went from 54 % to 0 in seconds the screen went out. So with all this being said is this my fault? Was going to try and call DJI this morning. Here’s a screen shot of what was on my screen seconds before.

 

[CyrusBlack]

rare yes but not impossible battery puffing and violent stops and manouvers flying in sport mode can and have caused batteries to fall out

I quit Battery Puffing many years ago and feel much better!

 

[DanMan32]

And with the battery design at least with M2, although latch detection should occur if either latch is pushed in, just one not latched it doesn't push in far enough to be detected.

 

[sar104]

The battery didn't disconnect in this case - cell 3 simply collapsed.

 

[RickinWaST]

As a first time drone owner (M2P) these battery issues that have been posted lately (At least it’s seems?) are helpful. Ensure one checks and monitor the voltage levels.

 

[Jcastro1836]

So unfortunately my 1 yr warranty has expired so DJI says regardless what the issue was the will not cover anything.

 

[DanMan32]

That's where Refresh Plus would come in handy.

 

[Paul Schulze]

I purchased a M2Z three weeks ago and on its second flight, the voltage dropped from 65% to 10%, an alarm sounded and an on screen warning displayed and then the voltage jumped back above 60% after I panicked. The log showed absolutely nothing. ?. I am now flying with guarded caution. I reported this in this forum.