DJI min 3 fell just before landing

[njb1]

Hi all, bought a DJI mini 3 about 6 weeks ago. Done a few test flights and a couple of filming runs. Today I was doing some aerial shots in the garden. Didn't fly far, or for long. After 3 mins I was flying it back and there was a noticeable change of prop noise and big wobble. It then steadied and a second or so later just fell to ground. No obstacles anywhere near. Landed in the grass and seemed OK, props free spinning. Tried a test launch and it slewed sideways into the grass. On closer inspection there is a small crack around the front right motor so it can flex.

Battery was charged yesterday and I did maybe 5-10 mins of successful flying. Was at 65% today which I thought would be fine for flying around the garden.

Have managed to look at the flight log and it shows "Motor error. Check propellers and fly with caution." while in flight. A second or so later "Motor unable to rotate. Check for objects blocking motor or contact DJI Support for assistance..; Motor stuck. Check for objects blocking motor or contact DJI Support for assistance (Code: 30165)" which I guess is when it fell or maybe when it hit the ground.

I put the log here:

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Is that visible?

What's the best next step? Is this likely to be covered by any warranty? DJI just seem to have an automated service request system. Or am I better off sending it back to the retailer (Very)?

 

[RodPad]

Welcome to the forum.
The log works!
I see so many things that I don't understand.

I be waiting for the real guys.

Rod..

 

[slup]

Below is the relevant telemetry from the last 15sec of the flight (click on the chart to make it larger), the graphs cover yaw, pitch, roll & all 4 stick commands (dashed & value 1024=neutral stick), check the legend in the bottom of the chart to see which is which.

Have placed the chart marker at 179,5sec where the drone does a short odd uncommanded movement... it turns CCW, pitch nose down & rolls to the right side (indicating a loss of thrust from the front right side). A second later it returns yaw wise but both roll & pitch are slightly more unstable than before. Then at 186sec the same movement repeats but this time the drone doesn't recovers, instead it goes down spinning CCW until it hits the ground & there the motor errors are initiated, the ESC stalls due to the blocked motors & due to that the motors are shut off to protect the electronics.

The cause for this is very likely the crack you discovered around the front right motor, my guess is that it was created or became worse there at 179,5sec... & then later caused the crash.

 

[slup]

Then a tip for future flights... always wait until "the lady voice" announces that the home point have been recorded before you take off & fly out horizontally.

In your crash flight the HP was recorded 16,3sec into the flight, there the GPS level reached 4 of best 5 & the HP could be recorded... but that wasn't from where you took off. Thing's like this can turn out to be disastrous if you lose connection & the failsafe action kicks in & brings your drone to another location than what you expect.

(Click on the pic below to make it larger)

 

[RodPad]

slup

mavicpilots.com

I seen the HP in the wrong place on the my first view.
But why it actually crashed, all the info you posted OMG!

Rod ..

 

[njb1]

Thanks for that analysis. It does match with what I saw. Just wonder how it happened. As it happened mid flight after several event free flights I hope it'll be covered by warranty.

 

[slup]

...Just wonder how it happened.

Really impossible to say, cracks in thin plastic parts can occur due to many reasons... material fatigue around some imperfection in the molded part..? Something coming from how it have been treated during use or storage since it left the production line..?

 

[Capt KO]

Worth trying the warranty, think you will be pleasantly surprised. Good luck and hope you will post the results.

 

[JLind007]

Hi all, bought a DJI mini 3 about 6 weeks ago. Done a few test flights and a couple of filming runs. Today I was doing some aerial shots in the garden. Didn't fly far, or for long. After 3 mins I was flying it back and there was a noticeable change of prop noise and big wobble. It then steadied and a second or so later just fell to ground. No obstacles anywhere near. Landed in the grass and seemed OK, props free spinning. Tried a test launch and it slewed sideways into the grass. On closer inspection there is a small crack around the front right motor so it can flex.

Battery was charged yesterday and I did maybe 5-10 mins of successful flying. Was at 65% today which I thought would be fine for flying around the garden.

Have managed to look at the flight log and it shows "Motor error. Check propellers and fly with caution." while in flight. A second or so later "Motor unable to rotate. Check for objects blocking motor or contact DJI Support for assistance..; Motor stuck. Check for objects blocking motor or contact DJI Support for assistance (Code: 30165)" which I guess is when it fell or maybe when it hit the ground.

I put the log here:

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Is that visible?

What's the best next step? Is this likely to be covered by any warranty? DJI just seem to have an automated service request system. Or am I better off sending it back to the retailer (Very)?

Wow that was cool flight log. My drone did something similar. I was doing a short about 2 min. flight and bringing it back because i saw the battery was at 5 percent. On the way back it just fell down, it was only about 7 feet high. I received a Gimbal error 400111 code. So i used Python to re-adjust the Gimbal. The app didn't seem to work on readjusting the Gimbal. After readjusting the Gimbal with Python, then the app started working. Not sure why.

 

[RodPad]

JLind007

mavicpilots.com

Welcome to the forum!

It would be great if you make a post here:

Pilot Check In

mavicpilots.com

I your going to hang around here for awhile, put something in the signature.

Rod..

 

[msinger]

I have attached the log

Your flight log has not been attached.

 

[osibek]

Your flight log has not been attached.

Attached

 

[msinger]

Attached

I still cannot see it.

It would be best to start your own thread.

 

[Nickheale]

Below is the relevant telemetry from the last 15sec of the flight (click on the chart to make it larger), the graphs cover yaw, pitch, roll & all 4 stick commands (dashed & value 1024=neutral stick), check the legend in the bottom of the chart to see which is which.

Have placed the chart marker at 179,5sec where the drone does a short odd uncommanded movement... it turns CCW, pitch nose down & rolls to the right side (indicating a loss of thrust from the front right side). A second later it returns yaw wise but both roll & pitch are slightly more unstable than before. Then at 186sec the same movement repeats but this time the drone doesn't recovers, instead it goes down spinning CCW until it hits the ground & there the motor errors are initiated, the ESC stalls due to the blocked motors & due to that the motors are shut off to protect the electronics.

The cause for this is very likely the crack you discovered around the front right motor, my guess is that it was created or became worse there at 179,5sec... & then later caused the crash.

View attachment 165517

Hello, I wanted to share my flight log with you. I have a mini 3 pro and had mostly same experience.
Here's my flight log

DJI Flight Log Viewer - PhantomHelp.com

This is really scary and i'm afraid of flight at high altitudes now

 

[slup]

...I have a mini 3 pro and had mostly same experience... This is really scary and i'm afraid of flight at high altitudes now

Similar to the OP's incident, yours also indicate a loss of thrust... but from the rear right corner.

During the logged flight it's 3 instances where this happens, the first where the drone loses +200ft in height but then recovers & later 2 kind of glitches with no significant height loss. All instances coincide with a motor message in the log message stream (below)

The recorded telemetry (below from the first instance) shows a initial sudden attitude change where the drone pitch up then rotates CW... the drone also roll to the right, but to what amount it's uncommanded is hard to say as you there shortly command roll right with the right stick in full right position... all together though, is indicating that the rear right can't generate enough thrust.

Here you can see the movements in pitch, roll & yaw, have placed a chart marker where it starts.



The log doesn't contain any info about what failed, besides the "Motor unable to rotate" messages. Check the motors & make sure they can rotate smoothly & that it isn't any debris inside, then check so both prop blades are in good condition & can move freely without sticking in any position.

 

[RodPad]

@Nickheale

Welcome to the forum!

I hate the posts when a new member, I crashed or lost it.

I learn a lot from theses forums.

Rod ..

 

[Nickheale]

Similar to the OP's incident, yours also indicate a loss of thrust... but from the rear right corner.

During the logged flight it's 3 instances where this happens, the first where the drone loses +200ft in height but then recovers & later 2 kind of glitches with no significant height loss. All instances coincide with a motor message in the log message stream (below)

View attachment 173604The recorded telemetry (below from the first instance) shows a initial sudden attitude change where the drone pitch up then rotates CW... the drone also roll to the right, but to what amount it's uncommanded is hard to say as you there shortly command roll right with the right stick in full right position... all together though, is indicating that the rear right can't generate enough thrust.

Here you can see the movements in pitch, roll & yaw, have placed a chart marker where it starts.

View attachment 173605

The log doesn't contain any info about what failed, besides the "Motor unable to rotate" messages. Check the motors & make sure they can rotate smoothly & that it isn't any debris inside, then check so both prop blades are in good condition & can move freely without sticking in any position.

Thanks a lot for explaining this to me.
I checked the motors and replaced all props with new ones, I'm not getting and error messages for now but I'm still afraid to fly at high altitudes. I mean this time it took 4 seconds to recover, next time it may not recover at all.

I also noted that 1 second before the motor error message cell deviation went from 0.012v to 0.001v and 1 second after from 0.001 to 0.04v, i guess that's when it tried to recover.

Do you think it's the battery that caused the lack of trust

Last guess is because of the strong winds

 

[slup]

I also noted that 1 second before the motor error message cell deviation went from 0.012v to 0.001v and 1 second after from 0.001 to 0.04v...

Do you think it's the battery that caused the lack of trust

Last guess is because of the strong winds

Cell deviations up on about 0,07-0,1V occasionally is perfectly normal for a lithium battery... it's only when the deviations is high + rather constant you need to worry. And by worry I mean, worry about the health of the battery & that a cell can totally fail... which will end up in a far to low total battery voltage to power the motors.

A large deviation in it self will not cause motor RPM disturbance, as long as the total battery voltage is enough to keep them going & reaching max specified RPM.

So no... battery cell voltage deviations up on 0,04V will never cause motor RPM disturbances that in turn disturb the amount of thrust that is generated.

Wind... no, drones doesn't tumble & lose 200ft in height in wind gusts, they drift with the wind.

Thrust loss is coming from either a motor that can't rotate as fast as required or props that can't create enough thrust... in other words, either motor or prop failure.

 

[Nickheale]

Well i can’t thank you enough for all these details informations

I have all props changed and wanted to share the old one with you. If it’s not the prop then definitely motor problem

 

[MS Coast]

Well i can’t thank you enough for all these details informations

I have all props changed and wanted to share the old one with you. If it’s not the prop then definitely motor problem

View attachment 173611

Are those the props from the right rear motor?

Are those two the only props that showed damage? Were they paired on one motor?