1 week old Mavic Air 2 crash

[bladski]

Returning from home about a mile away and just fell out of the sky!

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

 

[old man mavic]

welcome to the forum,sorry your first post had to be sad news ,

 

[bladski]

Thanks Old Man, my first drone was the Mavic Mini and I was always worried about it falling out of the sky because it was so small and that's what made me get the Mavic Air 2. In the end the Mavic Air 2 lasted less than the Mini.

Is there any way to feel fully confident and fear free when taking your drone out for a flight?

The only 2 things I can think of are to have drone insurance and attach a lightweight tracker of some kind.

 

[old man mavic]

Thanks Old Man, my first drone was the Mavic Mini and I was always worried about it falling out of the sky because it was so small and that's what made me get the Mavic Air 2. In the end the Mavic Air 2 lasted less than the Mini.

Is there any way to feel fully confident and fear free when taking your drone out for a flight?

The only 2 things I can think of are to have drone insurance and attach a lightweight tracker of some kind.

every flight has the potential for disaster,all we can do as UAV pilots is to minimise those risks as much as possible we can do this by regular pre flight checks to make sure the UAV is airworthy, the batteries are fully charged, and when it comes time for take off ,that we give the RC time to aquire enough sats, that the compass is aligned correctly ,we have done a risk assessment of the surroundings where we intend to fly, and have checked that there are no airspace restictions in the area we intend to fly,i have a 5 million pound third party cover incase my UAV decides to plummet to earth and fly within the drone code after hundreds of flights i am still relieved when i can come home from a day out flying with my UAVs in one piece and no issues ,but sometimes a little fear is a good thing ,as being over confident can cause you to end up in situations out of your control,

 

[slup]

Returning from home about a mile away and just fell out of the sky!

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

This looks like a propulsion failure for a so far unknown reason ... either a prop or a motor. Decoding the initial pitch (goes positive), roll (goes negative) & yaw (goes CCW) directions suggests that it might have been the rear left that failed. If you share the mobile device .DAT log ending with FLY033.DAT we can have a look at the motor data.

 

[bladski]

This looks like a propulsion failure for a so far unknown reason ... either a prop or a motor. Decoding the initial pitch (goes positive), roll (goes negative) & yaw (goes CCW) directions suggests that it might have been the rear left that failed. If you share the mobile device .DAT log ending with FLY033.DAT we can have a look at the motor data.

View attachment 103274

Fascinating!

Well, here's that file (attached). I'm quite excited.

 

[Max L]

Similar problem. Today was up around 300' and a brief orange "error message" then my display began tumbling end over end, then went white. Just got it back a bit ago. Gimbal dangling, one arm broken dangling. Wondering if anyone even has parts for them yet smh.

 

[sar104]

Fascinating!

Well, here's that file (attached). I'm quite excited.

Unfortunately the DAT conversion is missing most of the motor data, but it does include the pulse width modulation from which much can be inferred:



Specifically, at 166.7 seconds the rear left ESC abruptly demanded full speed in response to craft control loss. That means that the rear left motor lost thrust, most likely due to prop loss but it could have been motor failure. That would require the motor speed data to determine and I'm sure it is in there somewhere - we just need @BudWalker to figure out why it is not appearing.

 

[BudWalker]

Unfortunately the DAT conversion is missing most of the motor data, but it does include the pulse width modulation from which much can be inferred:

View attachment 103300

Specifically, at 166.7 seconds the rear left ESC abruptly demanded full speed in response to craft control loss. That means that the rear left motor lost thrust, most likely due to prop loss but it could have been motor failure. That would require the motor speed data to determine and I'm sure it is in there somewhere - we just need @BudWalker to figure out why it is not appearing.

Poof!! it is done. But, you gotta be using the current version - 3.7.6. You should have seen this popup


Unfortunately, this popup won't appear if you've elected to not have CsvView/DatCon check for updates.



Anyway, the motor data shows the leftBack being commanded 100% and a current 3 times the other motors. It appears that is followed by a couple of seconds with no motor data being recorded. After that the leftBack speed is > 27K rpm. Not sure I believe that and it's odd that commanded, current and speed are all increased. An obstructed motor would cause current to increase and speed to decrease. And, a lost prop would result in lower current and higher speed.


To determine which quadrant has the lost propulsion I've started using the totalGyro data. Using the attitude data can be confusing sometimes.

Here it can be seen that the MA2 is rolling CCW, pitching up end over end, and rotating CCW. All consistent with the leftBack losing propulsion.

 

[sar104]

Poof!! it is done. But, you gotta be using the current version - 3.7.6. You should have seen this popup
View attachment 103354

Unfortunately, this popup won't appear if you've elected to not have CsvView/DatCon check for updates.
View attachment 103355


Anyway, the motor data shows the leftBack being commanded 100% and a current 3 times the other motors. It appears that is followed by a couple of seconds with no motor data being recorded. After that the leftBack speed is > 27K rpm. Not sure I believe that and it's odd that commanded, current and speed are all increased. An obstructed motor would cause current to increase and speed to decrease. And, a lost prop would result in lower current and higher speed.
View attachment 103353

To determine which quadrant has the lost propulsion I've started using the totalGyro data. Using the attitude data can be confusing sometimes.
View attachment 103357
Here it can be seen that the MA2 is rolling CCW, pitching up end over end, and rotating CCW. All consistent with the leftBack losing propulsion.

Curious - DatCon is set to check for updates and usually does announce, but not this time. I quit it and relaunched a few times, but no message.

Those are somewhat odd data from the rear left - I'll take a look. How much do we trust the motor current data from the newer models? I've noticed that the sum of the motor currents significantly exceeds the total battery current draw.

EDIT: I just realized that "Check for updates on startup" was checked, but "Show when newer version is available" had somehow become unchecked. Fixed. So why two settings there - why check for updates you don't want to know the outcome?

 

[BudWalker]

Curious - DatCon is set to check for updates and usually does announce, but not this time. I quit it and relaunched a few times, but no message.

Those are somewhat odd data from the rear left - I'll take a look. How much do we trust the motor current data from the newer models? I've noticed that the sum of the motor currents significantly exceeds the total battery current draw.

The .datCon file in your home directory should have a line that looks like
checkUpdates:true

I've only looked at a few very short MA2 .DATs and this one. So not enough to be totally confident of any of the data. But, the current data looks plausible to me. With the exception of the >27K rpm values the speed data also looks plausible.

 

[bladski]

When someone in the forum mentioned these drones are as far way from being a toy as you could imagine, I'm actually seeing that now.

Great analysis (nice "no data" annotation on the graph), I'm also able to pick up on a few things now thanks to your explanations.

Really appreciate your time guys thanks a lot.

 

[BudWalker]

......

EDIT: I just realized that "Check for updates on startup" was checked, but "Show when newer version is available" had somehow become unchecked. Fixed. So why two settings there - why check for updates you don't want to know the outcome?

You're right. I'll fix that in the next version.

 

[slup]

...An obstructed motor would cause current to increase and speed to decrease. And, a lost prop would result in lower current and higher speed.

Could the increased current be a peak in order to spin up to max RPM's ... and what can the decreasing RPM & current values just before the log ends mean?

 

[bladski]

Hi again chaps,

Just wanted to update you all on what happened with this.

I raised a "Fly away case" with DJI, that's what they call these issues and I explained everything, sent them the various log and DAT files and the cached video of the flight.

After a week or so they got back to me and alongside other stuff in the email, the main thing was this:

"The unfortunate incident that occurred to your aircraft has been confirmed as a warranty case according to our data analysis. If the aircraft cannot be recovered, we would like to offer you a replacement, Mavic Air 2 (without the remote controller and battery charger)."

I was of course very happy to read this and I admire DJI for acting with integrity. I think I am now a customer for life.

Thanks again for all your help and input on the subject here in the forum.

 

[Max L]

Thats awesome!

 

[itsneedtokno]

I'm glad to hear of a good DJI experience.

Too many bad ones out there.

 

[Joe Blow]

Is it possible an Eagle or Hawk attacked it and broke off the propeller?