Flight-log analyzing assistance requested

[joeflyer]

I was flying a Mavic Air 2 with a Smart Controller under a roof structure of an outdoor parking lot. At an altitude of about 3 feet while flying forward, the aircraft suddenly dropped to the pavement. No visible damage, probably due to the forward motion. It's a long (16-minute) file, and the incident is at the very end. I would appreciate any assistance with understanding what may have happened. Also, shouldn't the bottom sensor have prevented the problem?

DJI Flight Log Viewer | Phantom Help

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[Meta4]

I was flying a Mavic Air 2 with a Smart Controller under a roof structure of an outdoor parking lot. At an altitude of about 3 feet while flying forward, the aircraft suddenly dropped to the pavement. No visible damage, probably due to the forward motion. It's a long (16-minute) file, and the incident is at the very end. I would appreciate any assistance with understanding what may have happened. Also, shouldn't the bottom sensor have prevented the problem?

Looking at the end of your flight, from 14:53, you were flying straight and level with the drone 6 ft above the surface.
You were in Normal Mode with the right stick full forward on a heading of 240°.

Something odd happens at 15:00.2.
The data suggests that the drone started to rotate clockwise at about 60° per second, while still flying forward and level at 13 mph.
Do you remember if the drone started rotating while flying forward?
This would have only been about 2.5 sec before the drone started losing height.

At 15:03.4 it starts to lose height and rolls significantly to the right.
The pitch angle goes beyond normal limits, to almost 50°.

 

[joeflyer]

Here is the video of the end of the flight. The aircraft makes a slight turn to the right at about the same time that it descends. My intent was to hover the aircraft a few feet in front of me. I wonder if I incorrectly moved the left stick, causing the descent. Even if I did, shouldn't the bottom sensors have prevented the crash?

 

[Meta4]

Here is the video of the end of the flight. The aircraft makes a slight turn to the right at about the same time that it descends. My intent was to hover the aircraft a few feet in front of me. I wonder if I incorrectly moved the left stick, causing the descent.

It looks like the drone flew into the ground.
There's no joystick input that would have caused any change in height or deviate from straight flight.

The video shows that the drone didn't actually start rotating three seconds before the crash, as the data indicates.
One possible explanation for this would be a strong magnetic field deflecting the compass at that point.
I'm not sure how that would cause the drone to dive into the floor.

Was the flying height about 6 feet above the floor?

Even if I did, shouldn't the bottom sensors have prevented the crash?

The shaded black surface may have been difficult for the VPS sensors to do their thing properly?

 

[joeflyer]

I initially wrote 3 feet, but I think 6 feet is more accurate. I didn't think I moved the sticks, but I can't figure out why the aircraft dove into the pavement. There are solar panels on the roofs, and EV charging stations. Maybe they had something to with the crash, though I have flown there before with no problem.
Thanks for your input.

 

[MavicBob]

Help! ... with analysis of flight file in Dropbox folder (access w/ above QR code).

My Mavic 2 Pro became non-responsive after 3:46 into a flight in calm, clear weather. Recovered video shows it had 20+ feet altitude and no visible obstacles. I've held a Type 107 certificate for 5 years with 90+ hours of air time. Have looked at the Excel flight log and am at a loss.

Any assistance is much appreciated.

 

[Meta4]

Help! ... with analysis of flight file in Dropbox folder (access w/ above QR code).

My Mavic 2 Pro became non-responsive after 3:46 into a flight in calm, clear weather. Recovered video shows it had 20+ feet altitude and no visible obstacles. I've held a Type 107 certificate for 5 years with 90+ hours of air time. Have looked at the Excel flight log and am at a loss.

Any assistance is much appreciated.

So after messing about for far too long to find a way to read the qr code into the computer, I find that you have uploaded the airdata CSV file.
That's not good enough.
Please post a simple link to your Airdata report so I can get the .txt file and see a lot more info about the flight.

 

[MavicBob]

So after messing about for far too long to find a way to read the qr code into the computer, I find that you have uploaded the airdata CSV file.
That's not good enough.
Please post a simple link to your Airdata report so I can get the .txt file and see a lot more info about the flight.

This ought to take you directly to the dropbox folder with the report inside (two versions):

Dropbox - File Deleted - Simplify your life

www.dropbox.com

 

[MavicBob]

So after messing about for far too long to find a way to read the qr code into the computer, I find that you have uploaded the airdata CSV file.
That's not good enough.
Please post a simple link to your Airdata report so I can get the .txt file and see a lot more info about the flight.

Thanks for helping, here's a link to the dropbox folder with two versions of the flight log:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

 

[slup]

Thanks for helping, here's a link to the dropbox folder with two versions of the flight log:

Dropbox - File Deleted - Simplify your life

www.dropbox.com

No, that's just a downloaded Airdata.csv, an Excel sheet & a .png picture... the complete link directly to that flight on Airdata is needed.

Do like this, it's a simple 2 step process to get a link you can share here...

Go to the flight on your Airdata account & hit the green button top right...



Then mark what you want to share from the log... the default marking is sufficient. Then hit the button mid bottom...



You will get a link... copy it & come back here and share it in a new post.

 

[MavicBob]

No, that's just a downloaded Airdata.csv, an Excel sheet & a .png picture... the complete link directly to that flight on Airdata is needed.

Do like this, it's a simple 2 step process to get a link you can share here...

Go to the flight on your Airdata account & hit the green button top right...

View attachment 169758

Then mark what you want to share from the log... the default marking is sufficient. Then hit the button mid bottom...

View attachment 169759

You will get a link... copy it & come back here and share it in a new post.

have never done a direct share - very helpful, thanks!
Here's the link:

 

[MavicBob]

This ought to take you directly to the dropbox folder with the report inside (two versions):

Dropbox - File Deleted - Simplify your life

www.dropbox.com

OK, haven't created a direct link before; here it is:

 

[slup]

Here's the link...

Ok... so you flew with Litchi, these logs usually contain a bit less info than if using the DJI GO4 app.

Fortunately this log shows a possible cause anyway...

The flight ends without any special abrupt attitude changes, the AC just goes down when it was flying in approx. 31mph & you commanded a wide turn with the elevator, aileron & rudder stick. Nothing indicate a collision what so ever... so this incident don't have any cause coming from how you manoeuvred the AC or your flying experience.

If looking at the log in a chart form with some chosen telemetry data as graphs... we see that everything that has to do with electrical power/battery starts to "flat-line" at about 155sec into the flight where your craft was in the second turn. All data that has to do with speeds & AC attitudes continue there to behave normal.

This indicate that something have started to happen with the AC power supply, the battery have stopped to communicate with the flight controller.

(Click on the chart to make it larger, a chart marker is placed at 155sec & data values from there can be read out from the legend below the chart area)


The battery still provide power to the motors after 155sec, so the flight continues until 226sec where the log indicate that the motors have stopped... & the AC goes down.

(Click on the chart to make it larger (this is a enlargement of the very end of the log) , a chart marker is placed at 226sec & data values from there can be read out from the legend below the chart area, note that there the log says "NotMotorsOn")


The cause for this incident is most likely due to a failing power supply... either due to a slowly ejecting battery or a fault in some of the AC's electronic components.

 

[MavicBob]

Ok... so you flew with Litchi, these logs usually contain a bit less info than if using the DJI GO4 app.

Fortunately this log shows a possible cause anyway...

The flight ends without any special abrupt attitude changes, the AC just goes down when it was flying in approx. 31mph & you commanded a wide turn with the elevator, aileron & rudder stick. Nothing indicate a collision what so ever... so this incident don't have any cause coming from how you manoeuvred the AC or your flying experience.

If looking at the log in a chart form with some chosen telemetry data as graphs... we see that everything that has to do with electrical power/battery starts to "flat-line" at about 155sec into the flight where your craft was in the second turn. All data that has to do with speeds & AC attitudes continue there to behave normal.

This indicate that something have started to happen with the AC power supply, the battery have stopped to communicate with the flight controller.

(Click on the chart to make it larger, a chart marker is placed at 155sec & data values from there can be read out from the legend below the chart area)
View attachment 169782

The battery still provide power to the motors after 155sec, so the flight continues until 226sec where the log indicate that the motors have stopped... & the AC goes down.

(Click on the chart to make it larger (this is a enlargement of the very end of the log) , a chart marker is placed at 226sec & data values from there can be read out from the legend below the chart area, note that there the log says "NotMotorsOn")
View attachment 169783

The cause for this incident is most likely due to a failing power supply... either due to a slowly ejecting battery or a fault in some of the AC's electronic components.

Slup - thank you so much for your time and expertise... very helpful. I do recall seeing the word "Battery" appearing on my iPad screen very shortly before the drone becoming unresponsive. Perhaps there was an internal malfunction that's not more fully apparent. I just checked the battery clamps and they appear fully operable. One of life's many mysteries...