Had a fly away that landed in the lake

[Slloyd]

Yesterday I had just launched my craft and was setting camera settings when my wife yells "what are you doing?" I look up to the drone flying into a tree and crashing into the lake..
I had no control and wasn't using the sticks at all. I just contacted DJI and they said because it is out of warranty. (Mar 9, 2019 purchase and I let DJI care expire) that there would be a $65 dollar fee to look at it and then what ever cost would be my responsibility. I asked if it was not user error would DJI cover it and they said no. Out of warranty no free. I am wondering if someone could tell my what happened?
Thanks for any help.
Scott

 

[WithTheBirds]

Will be interesting to see what a detailed log analysis reveals- from a quick glance at what is depicted in airdata it appears this was a driftaway, there were insufficient satellites available for GPS positioning and you let it drift into the tree. Had your wife alerted you earlier you could have flown manually to avoid this unfortunate outcome.

 

[Starz]

Ever launch from that spot before?

 

[Meta4]

I look up to the drone flying into a tree and crashing into the lake..
I had no control and wasn't using the sticks at all.

Here's what that data looks like: DJI Flight Log Viewer - PhantomHelp.com
You can see the joystick input there.

The data shows you launching and hovering at the launch point until 0:13.8 when the data shows the right stick pulled hard to the left for 7 seconds.
That took the drone about 100 ft east, out over the water.
At 0:21.2 as the drone is slowing down, the data shows something unusual.
The drone rolls hard to its right and accelerates toward the W without any corresponding joystick input.
The drone stays roll ed left until 0:24.2 when you start giving confusing extreme full stick input with both joysticks in multiple directions.
It looks like the drone may have collided with an obstacle at 0:25.1 and obstacle warnings start showing in the log.
From 0:27.1 the drone has rolled over >90 degrees and starts to lose height and it's confusing to work out what you were doing with the extreme joystick moves, but it doesn't save the drone which falls.
GPS appears to have been good until the drone was rolled or tipped sideways where the antenna was no longer pointed to the sky.

 

[boblui]

Can be due to errors of some sensors such as the compass. Will need the .DAT flight log file in the phone for further analysis : follow this thread to get the file : Mavic Flight Log Retrieval and Analysis Guide

 

[Phantomrain.org]

My collection of Posts of landing in the Lake is expanding, the reasons of course do vary but the loss of a drone is devastating.

Phantomrain.org
Get a Rescue jacket and save your drone.

 

[alopeznj]

Whenever I fly in a place where ground altitude and geo is very different, I re calibrate everything. Never had a problem. But when I change atmosphere like hundreds of miles from last calibration it does not act well.
Some dissagree but I calibrate compass and IMU whenever I change take-off palces by 50 miles.

 

[Meta4]

Whenever I fly in a place where ground altitude and geo is very different, I re calibrate everything. Never had a problem. But when I change atmosphere like hundreds of miles from last calibration it does not act well.
Some dissagree but I calibrate compass and IMU whenever I change take-off palces by 50 miles.

Some disagree because they understand what recalibrating actually does and when it might really be needed.
What you are doing achieves nothing.
You are using recaibration as a superstitious ritual.

It's hard to see how your comment is relevant to this incident.

 

[alopeznj]

Some disagree because they understand what recalibrating actually does and when it might really be needed.
What you are doing achieves nothing.
You are using recaibration as a superstitious ritual.

It's hard to see how your comment is relevant to this incident.

Its not so relevant, why I posted on another DJI post. But to the original post. Calibrating often comp and IMU has been great for me. Just a thought.
I cant say it is useless because when ever I move to a diffrent elevation, its a good flight after calibrating. Maybe Im just lucky. Personally I recommend Compass and IMU calibration when you move to diffrent elevation. Works for me. Of course there are more experienced pilots here and maybe I am wrong. But seems to work for me. Example: I take pre-flight serious. Checked everything at home on my mini and was 100% good to go. Went to upstate NY and setup. EVERYTHING was off. had to calibrate Compass and IMU. Then... great flight. No issues with fly away, considering it was windy for a Mini and started to rain. Emergency RTH put that aircraft on my lap. NO complaints. Even got a bit wet and no damage.

What I am having trouble with is Choppy image. That I do not think is relevant to this post.

 

[Meta4]

Its not so relevant, why I posted on another DJI post. But to the original post. Calibrating often and IMU has been great for me. Just a thought.
I cant say its useless because when ever I move to diffrent elevation, its a good flight after calibrating. Maybe Im just lucky.
Personally I recommend Compass and IMU calibration when you move to diffrent elevation. Works for me.
Of course there are more experienced pilots here and maybe I am wrong. But seems to work for me.

What you are saying is that it hasn't caused a problem.
But not doing it wouldn't have caused a problem either.

Recalibrating unnecessarily doesn't make anything any better or safer.
Compass calibration has nothing at all to do with where you are or how far you've moved from somewhere else.
It's 100% unrelated.

FYI .. I haven't ever calibrated anything on my main work drone.
It's travelled to a few different countries, flown 4000 miles and over 1000 flights in almost 4 years and still goes as well as it did on day 1.
That works for me too.

 

[boblui]

The IMU has got some problem. This is my analysis :

 

[Slloyd]

Ever launch from that spot before?

no

 

[Slloyd]

Here's what that data looks like: DJI Flight Log Viewer - PhantomHelp.com
You can see the joystick input there.

The data shows you launching and hovering at the launch point until 0:13.8 when the data shows the right stick pulled hard to the left for 7 seconds.
That took the drone about 100 ft east, out over the water.
At 0:21.2 as the drone is slowing down, the data shows something unusual.
The drone rolls hard to its right and accelerates toward the W without any corresponding joystick input.
The drone stays roll ed left until 0:24.2 when you start giving confusing extreme full stick input with both joysticks in multiple directions.
It looks like the drone may have collided with an obstacle at 0:25.1 and obstacle warnings start showing in the log.
From 0:27.1 the drone has rolled over >90 degrees and starts to lose height and it's confusing to work out what you were doing with the extreme joystick moves, but it doesn't save the drone which falls.
GPS appears to have been good until the drone was rolled or tipped sideways where the antenna was no longer pointed to the sky.

the confusing sticks would be when I looked up and my wife was asking what I was doing as it was going into the tree.. no control from sticks that I could tell. It did colide with the tree then fell through the tree until it landed in water.
My question is the "unusual" ? What happened? I don't think I did anything but if it was user error please let me know. Thanks for your input.

 

[Slloyd]

The IMU has got some problem. This is my analysis :

thanks for that video!

 

[Slloyd]

Can be due to errors of some sensors such as the compass. Will need the .DAT flight log file in the phone for further analysis : follow this thread to get the file : Mavic Flight Log Retrieval and Analysis Guide

 

[fguthrie]

What you are saying is that it hasn't caused a problem.
But not doing it wouldn't have caused a problem either.

Recalibrating unnecessarily doesn't make anything any better or safer.
Compass calibration has nothing at all to do with where you are or how far you've moved from somewhere else.
It's 100% unrelated.

FYI .. I haven't ever calibrated anything on my main work drone.
It's travelled to a few different countries, flown 4000 miles and over 1000 flights in almost 4 years and still goes as well as it did on day 1.
That works for me too.

"But not doing it wouldn't have caused a problem either." - I disagree without having all the facts you can't assume that. Not calibrating the compass could cause an issue. I know on my M2P when I have taken the drone from one location to another many miles away and I do not calibrate the compass, I can get some unpredictable results. A calibration corrects the problem.

 

[slup]

"But not doing it wouldn't have caused a problem either." - I disagree without having all the facts you can't assume that. Not calibrating the compass could cause an issue. I know on my M2P when I have taken the drone from one location to another many miles away and I do not calibrate the compass, I can get some unpredictable results. A calibration corrects the problem.

The fact is that by doing a compass calibration you "measure" the aircraft's own internal magnetic disturbance so it can be deducted from the total sensed magnetic field so a correct measurement can be done of earth's geomagnetic field.

If you haven't changed the aircraft's own magnetic field through for instance attaching or detaching extra equipment a compass calibration is not necessary & will not change anything.

 

[Michael Ainsworth]

It looks like you launched from a pontoon on the side of the lake. There would have been a lot of metal in that pontoon such as bolts and fittings, this would have messed the compass up and then when it went up further from the interference the compass then gets a different reading.

Never calibrated my Mavic Pro. You will get a prompt to calibrate if it requires it. I know the newer ones are different but if you try to calibrate and do it near an area with interference you will mess it up.
I just make sure that I am away from any interference and that everything is good to go before take off. Also watch it take off and hover For a while to make sure nothing untoward is going on.

 

[fguthrie]

The fact is that by doing a compass calibration you "measure" the aircraft's own internal magnetic disturbance so it can be deducted from the total sensed magnetic field so a correct measurement can be done of earth's geomagnetic field.

If you haven't changed the aircraft's own magnetic field through for instance attaching or detaching extra equipment a compass calibration is not necessary & will not change anything.

If the aircraft is moved to a different location, the magnetic filed may also be different which would impact the aircraft and warrant a calibration. There are magnetic declination maps that show the distortions of the field and they have to be updated constantly as the shape of the field changes.

 

[Meta4]

If the aircraft is moved to a different location, the magnetic filed may also be different which would impact the aircraft and warrant a calibration. There are magnetic declination maps that show the distortions of the field and they have to be updated constantly as the shape of the field changes.

Although this idea is commonly held, it is completely wrong.
Compass calibration has nothing at all to do with where you are, how far you are from somewhere else or magnetic declination.
If you don't understand what compass calibration actually does, everything else you believe about compass calibration is probably wrong.
You;ll find a good explanation of what compass calibration is really about in the first post here:

A short explanation of compass function, calibration and errors.

BACKGROUND The aircraft compass is often misunderstood, both in terms of function and purpose, but it is important to understand what the compass measures, why, and what happens to that information. At the most basic level the purpose of the compass is to measure the earth’s magnetic field in...

mavicpilots.com

I know on my M2P when I have taken the drone from one location to another many miles away and I do not calibrate the compass, I can get some unpredictable results. A calibration corrects the problem.

Without analysing the flight data from your flights, we can't tell what your issue might have been.
But understanding what compass calibration does and what it can and cannot affect, we can be sure that taking your drone from one location to another many miles away and not recalibrating, was not the issue.