Mavic 2 Pro fly away upon pressing return home button.

[Deleted member 103366]

If you want help post the flight logs on here or a link to it on either Airdata or DJI Flight Log Viewer | Phantom Help

 

[Honeybush Swami]

If you’d like that DJI explanation checked, post the flight txt.
If you accept you pressed a landing button by mistake, then no further action required.
The log will certainly confirm it.

ok, yes.
I am having trouble in accessing that on the smart controller. Where can I get that text?

 

[Deleted member 103366]

See the bottom of that phantom help page mentioned in this thread

 

[MAvic_South_Oz]

ok, yes.
I am having trouble in accessing that on the smart controller. Where can I get that text?

Hmmm, very good question, and not sure @sar104 has that in his Mavic Flight Log Retrieval and Analysis Guide ??

Maybe something like @msinger has in his phantomhelp flight viewer instructions ??

HOW TO: Locate your DJI TXT flight logs

• For the Phantom 4 Adv/Pro + remote controller or DJI Smart Controller, connect your remote controller to a computer via a USB cable and go to “DJI\dji.pilot.pad\FlightRecord”. If needed, you can find detailed instructions here 235.

 

[Honeybush Swami]

Ok, I uploaded the flight record, but I do not understand it at all.!

 

[MAvic_South_Oz]

Ok, I uploaded the flight record, but I do not understand it at all.!

It is all gibberish there in the txt file, once uploaded to airdata or phantomhelp, you get a neat flight report.
(I'm having trouble getting it to work at the moment though @msinger . . . times out.)

Further, with other CSV tools, you can really get into some very fine info (well above my head for now).

Someone will get it uploaded somewhere and check no doubt.

 

[sar104]

Hmmm, very good question, and not sure @sar104 has that in his Mavic Flight Log Retrieval and Analysis Guide ??

Maybe something like @msinger has in his phantomhelp flight viewer instructions ??

HOW TO: Locate your DJI TXT flight logs

• For the Phantom 4 Adv/Pro + remote controller or DJI Smart Controller, connect your remote controller to a computer via a USB cable and go to “DJI\dji.pilot.pad\FlightRecord”. If needed, you can find detailed instructions here 235.

The SC is basically an Android device, and the location depends on whether you are using the GO 4 app or the Pilot app:

 

[MAvic_South_Oz]

Ok, I uploaded the flight record, but I do not understand it at all.!

Post 25 above.

I've tried to upload that again to phantomhelp, times out.
Anyone else had a shot ?
Or tried Airdata ?

 

[slup]

My Mavic 2 pro was returning... I pressed the return home button and it came close, but then disconnected and drifted away.

Sorry for your loss ... but your recollection of the events & what you commanded the drone to do doesn't marry up with what the flight log show ... not at all.

I agree with DJI's assessment to 100% & you will not be able point this to any other than yourself.

At 978sec into the flight you gave the drone a land command through the app (that button is next to the RTH button on the app ...) ... probably by mistake.

Immediately the drone started to descend with 3m/s ... just in the end of the log at about 1008sec you apply a combination stick input (full forward speed + full down) ... when you started to do this the drone was at approx 13m above your HP. Shortly after the drone hit the water surface, still with you applying full stick inputs for forward & down... & the connection was lost as the water shorted the electrical system.

All is shown here in this chart with data from your shared flight log.

Blue background color is appcommanded autolanding.
Red graph is height relative your HP
Black graph is horizontal heading speed
Light blue is Zspeed (vertical speed ... positive value = descend)
And all 4 dashed graphs is stick inputs

(Click on the chart to make it larger)



And your drone went under here where the red circle is ...



Here on a 3D pic with the green flight path there in the end together with comments ...

(Click on the pic. to make it larger)

 

[Deleted member 103366]

Your log on Phantom help DJI Flight Log Viewer - PhantomHelp.com

 

[Honeybush Swami]

Sorry for your loss ... but your recollection of the events & what you commanded the drone to do doesn't marry up with what the flight log show ... not at all.

I agree with DJI's assessment to 100% & you will not be able point this to any other than yourself.

At 978sec into the flight you gave the drone a land command through the app (that button is next to the RTH button on the app ...) ... probably by mistake.

Immediately the drone started to descend with 3m/s ... just in the end of the log at about 1008sec you apply a combination stick input (full forward speed + full down) ... when you started to do this the drone was at approx 13m above your HP. Shortly after the drone hit the water surface, still with you applying full stick inputs for forward & down... & the connection was lost as the water shorted the electrical system.

All is shown here in this chart with data from your shared flight log.

Blue background color is appcommanded autolanding.
Red graph is height relative your HP
Black graph is horizontal heading speed
Light blue is Zspeed (vertical speed ... positive value = descend)
And all 4 dashed graphs is stick inputs

(Click on the chart to make it larger)

View attachment 137323

And your drone went under here where the red circle is ...

View attachment 137324

Here on a 3D pic with the green flight path there in the end together with comments ...

(Click on the pic. to make it larger)
View attachment 137328

I can see why you would say that, but I and a police officer witnessed the drone fly over us and into the forest!!!
I will have to get the police officers testimony. It did not land in the water! It is in the forest behind the beach and I will have to find it.
thanks for this anyalsys!!!!

 

[slup]

I can see why you would say that...
I will have to get the police officers testimony.

But anyhow ... you aren't the first or the last on this forum that will have their recollection of events in a stressful situation mixed up. I have yet to see a flight log that doesn't tell us what really happened. A police officers testimony will unfortunately not help you convince DJI.

Did you look at the PhantomHelp log viewer site that was linked to in post #30? That view might be easier to understand ...

This is what's shown in the very end of the log you provided ...

Check out the blue arrows I put in there ... & as usual, clicking on the picture makes it larger.

 

[Meta4]

I can see why you would say that, but I and a police officer witnessed the drone fly over us and into the forest!!!
I will have to get the police officers testimony. It did not land in the water! It is in the forest behind the beach and I will have to find it.

The data shows what actually happened.
What you think you saw and what actually happened are two different things.
The drone went into the water 800 ft out from the launch point.

 

[eEridani]

Except that most fresh water is non-conductive and won't short out electronics. If the lake was brackish, very brackish, or salt water, maybe, but even then probably not a rapid death. Loss of signal was the antenna altitude being sub-zero (perhaps even underwater) and the trees. And the drone reported WEAK SIGNAL; not loss of signal.

 

[eEridani]

As an aside, there may have been another drone in the sky that evening; drones aren't common things we see, but they're are up there. Especially in that neighborhood - those houses you flew over - enough money they might have a security company flying drones around and might even explain why cops showed up.

This camera view is also a hint your drone really was below tree level and descending into the lake.

 

[slup]

Except that most fresh water is non-conductive and won't short out electronics. If the lake was brackish, very brackish, or salt water, maybe, but even then probably not a rapid death. Loss of signal was the antenna altitude being sub-zero (perhaps even underwater) and the trees. And the drone reported WEAK SIGNAL; not loss of signal.

View attachment 137334

You're kidding yourself, all motors & the FC will short out very rapidly when the drone gets submerged... & to be clear, the ending of the log can only have 2 reasons ... either the motors stopped (TXT recording only runs motors on to off) or the control signal was interrupted (either due to electrical short circuit or going out of LOS) ... & was never regained.

In this case both the motors stopped & the drone went out of LOS ... what came first doesn't matter, both happened in a fraction of a second.

 

[eEridani]

My guess is the log stopped when the drone flipped over upon impacting the water (upward obstacle sensor blocked).

And, fresh water is generally non-conductive (I'll qualify that with - we are talking about low voltage here). Things do not short out instantly like you presume. Take your trusty non-waterproof flashlight - turn it on - and drop it into your filled kitchen sink, record how long it takes for the torch to dim. Then let's talk.

 

[slup]

... Things do not short out instantly like you presume.

Have you tried to drop your phone in water ... a phone which isn't water tight & have a detachable battery, I have & it died instantly.

And to be honest ... will this lead to another possible outcome for the drone in this incident ?

My guess is the log stopped when the drone flipped over upon impacting the water (upward obstacle sensor blocked).

And yeah ... it's a guess, but not based on the info provided in the log ... that message comes at 1014,8sec & the pitch, roll & yaw data doesn't show the drone to be nowhere near upside down. And there you also can see that it's 2 connection glitches before the drone goes off-line ... explaining the "weak signal" message.

 

[Deleted member 103366]

A question for Slup and or Meta 4, what message appears in the txt flight log if a M2P disconnects from the controller whilst the drone is in flight? (reason = I want to check something)

I have had at least one proper disconnection with a Mavic 2 but I can not remember which flight, scanning the csv's produced by a command line usage of TXTlogToCSVtool i.e.

FORFILES /m *.txt /C "TXTlogToCSVtool /c @file @fname.csv"

I find 5 flights where a "Weak signal" message is recorded but I am not certain it relates to a disconnection.

 

[Deleted member 103366]

A question for Honeybush Swami, since you are so adamant that the log is in error I have to ask, are you certain it is the correct log? Check the date and time stamp. I would also have a look and see if you can find any cached videos with a corroborating date and time stamp.
You would not be the first person to mix up logs.

Do you have the DAT flightlog for the posted log? See Sar104's post #27 in the MCDatFlightRecord foider, the name is probably 2021-10-20_18-13-04_FLY046.DAT.