Mavic Air 2 crash and lost. Error: "Motor is Blocked. Not Enough Force/ESC Error"

[leartsdrones]

Can't read out anything precise from the .TXT log more than it indicate a IMU error from the log event stream ... Airdata specifically mention the gyro.

From the log event stream:

View attachment 120874

And the same from Airdata:

View attachment 120873
Possibly the mobile device DAT log can reveal more ... the one for this flight ends with FLY011.DAT.

I would contact DJI about this ... seems to be a hardware failure.

Thanks for the detailed analysis friend. I am sending you the file: FLY011.DAT attached so that you can see if you can discover anything else.

 

[slup]

Thanks for the detailed analysis friend. I am sending you the file: FLY011.DAT attached so that you can see if you can discover anything else.

The DAT again show a major IMU failure starting from approx 745sec into the flight ...

From the DAT log event stream:


Lining up all available yaw data from the log:

Gyro=bright green against IMUYaw unwrapped=dark blue ... shows a good agreement.
IMUYaw=purple against VIOYaw=yellow shows a good agreement ... but adding in magYaw=black shows that the magYaw (compass) have a major disagreement with all other values indicating Yaw.

Easy to point out the compass as the major culprit here, but ... compass values rarely affect thing's so rapidly if failing on height, & together with what's stated in the event stream I should say it's the IMU that fails this time.



Another indication of IMU failure & a FC that's giving up is the velocity differences between the GPS & the IMU ... they should normally be very close to zero. Here all directions is affected, both North, East & height... starting from 745sec.



Contact DJI ... they will most probably cover this.

 

[Barbara]

Quick look at your log and it shows an "IMU error 30045" just before you started getting the "Not enough Force" messages.



An IMU error is potentially serious and could cause the aircraft to try and correct an attitude problem that doesn't exist. The motors spin up to max in vain ((Max force) and you loose control.

Why the IMU error happened? that's the next question.

 

[leartsdrones]

The DAT again show a major IMU failure starting from approx 745sec into the flight ...

From the DAT log event stream:
View attachment 120884

Lining up all available yaw data from the log:

Gyro=bright green against IMUYaw unwrapped=dark blue ... shows a good agreement.
IMUYaw=purple against VIOYaw=yellow shows a good agreement ... but adding in magYaw=black shows that the magYaw (compass) have a major disagreement with all other values indicating Yaw.

Easy to point out the compass as the major culprit here, but ... compass values rarely affect thing's so rapidly if failing on height, & together with what's stated in the event stream I should say it's the IMU that fails this time.

View attachment 120885

Another indication of IMU failure & a FC that's giving up is the velocity differences between the GPS & the IMU ... they should normally be very close to zero. Here all directions is affected, both North, East & height... starting from 745sec.

View attachment 120886

Contact DJI ... they will most probably cover this.

Thanks for the detailed analysis friend. We contacted DJI today. =)

 

[leartsdrones]

Quick look at your log and it shows an "IMU error 30045" just before you started getting the "Not enough Force" messages.

View attachment 120887

An IMU error is potentially serious and could cause the aircraft to try and correct an attitude problem that doesn't exist. The motors spin up to max in vain ((Max force) and you loose control.

Why the IMU error happened? that's the next question.

I believe that we will never know why this IMU error. DJI does not usually reveal. but if she send a new drone we will already be in profit. thanks!

 

[BudWalker]

This IMU error is a bit different. Usually, the possibility remains that the flight controller may be at fault. But, in this case the accelerometer and gyro data gets stuck suggesting that the fault lies with either the IMU or it's connection to the internal bus.

 

[slup]

Yep ... that is clearly spelled out in the even stream this time.

 

[ANTHONYBELGIUM]

Hey I have the same issue with my Air 2! All of a sudden multiple motor error messages, did auto RTH, but I couldn’t even force it to come down faster (took more than 1 min to drop from 30m the first time). I checked the propellors, nothing wrong so trief flying again, same error, but all of a sudden I donnt hear my drone any more and it just dropped out of the sky. It seemed like it dropped in an angle (left motors both off?), mid-drop it tried to restart engines? But nothing worked, it crashed. After that I have an ESC error. Tried everything. It was dirty, cleaned it as much as possible, refreshed firmware, but not working. Can anyone please tell me where to get those logs and analyze it?

 

[Thomas B]

Hey I have the same issue with my Air 2! All of a sudden multiple motor error messages, did auto RTH, but I couldn’t even force it to come down faster (took more than 1 min to drop from 30m the first time). I checked the propellors, nothing wrong so trief flying again, same error, but all of a sudden I donnt hear my drone any more and it just dropped out of the sky. It seemed like it dropped in an angle (left motors both off?), mid-drop it tried to restart engines? But nothing worked, it crashed. After that I have an ESC error. Tried everything. It was dirty, cleaned it as much as possible, refreshed firmware, but not working. Can anyone please tell me where to get those logs and analyze it?

Please start your own thread for this. It will avoid much confusion. Thank-you.

 

[deub]

Re post by hypershade.....drone crash
Slup & Meta4 have concluded crash was caused by motor failure.
The drone was flying backwards, which brings me to my queries.
I Have mavic 2 zoom.....When hovering,front 2 motors run hotter than
back 2 motors. When flying backwards,they run even hotter still.Could it be that sustained backwards flying could cause overheating and seizing of front motors. My flying is mostly done in high ambient temps...30-35c. Also when flying backwards,the internal fan, which vents towards the rear, would be fighting against the outside air movement. Probably not related to motor temp, but still a concern in high ambient. Any info on expected motor temp or am i just being a worrywart.

 

[Meta4]

When hovering,front 2 motors run hotter than
back 2 motors. When flying backwards,they run even hotter still.Could it be that sustained backwards flying could cause overheating and seizing of front motors.

No .. it makes no difference what direction you fly.
If it's a hot day and you run the motors hard, they get hot.

or am i just being a worrywart.

Yes

 

[deub]

Hello,worrywart here. Thanks for response.
Its just that i know that pre-lubed bearings life expectancy is shortened by high temps. Has to do with grease drying out.
Dont know what exact temp would be considered critical on these
small high rev drone motors. My front motors are approaching hot car engine temp when flying backwards. Any info anyone?

 

[Meta4]

My front motors are approaching hot car engine temp when flying backwards. Any info anyone?

For the motors any direction is forwards .. there is no "backwards"
It's normal for the motors to get hot when flying hard, particularly on hot days.
The motors and bearings DJI specced for their drones are easily able to handle the conditions you are flying under.

 

[deub]

Thanks for your response. I will hang up my worrywart hat.
Going to fly long litchi mission with drone "facing" backwards.
Best wishes.