Mavic air Crash: IMU heading error, followed by ESC error, What happened?

swadeky · Apr 14, 2020

Hello,

On probably my 15th flight with my new/used mavic air I was flying in a large canyon. I was using the tap fly feature but it didn't seem to be working or tracking well. When I started to return home I received a IMU heading error immediately followed by a "not enough force/esc error". At this point the drone started spinning out of control and I started losing video signal. It ended up crashing. I found the drone and I think its actually fine (landed in a shrub and not on the rock, lucky!).

I am wondering why this may have happened and if I should send the drone in or if i can check it/ do things so it doesnt happen again. ALl my flights with the drone prior were totally fine. I did notice that the firmware needed an update (I have been consistently updating it very recently), but i didn't have enough signal to update it before the flight. Maybe it was a bad firmware?

Here's a link to my flight data. Please let me know what you think! I have attached the flight data as well.

Thanks

sar104 · Apr 14, 2020

Can you locate the mobile-device DAT file ending FLY034.DAT? Figuring out what happened is going to require the raw sensor data. There were three periods of significant disagreement between the IMU velocity solution and the aircraft position:

The final one caused the crash.

swadeky · Apr 14, 2020

sar104 said:
Can you locate the mobile-device DAT file ending FLY034.DAT? Figuring out what happened is going to require the raw sensor data. There were three periods of significant disagreement between the IMU velocity solution and the aircraft position:

View attachment 98732

The final one caused the crash.

Thanks for getting back to me, I am working on getting that DAT file. I found this one and I think its the correct flight. Does this file work? otherwise I can try and get the other DAT file Im just having a bit of trouble accessing it for some reason.

sar104 · Apr 14, 2020

swadeky said:
Thanks for getting back to me, I am working on getting that DAT file. I found this one and I think its the correct flight. Does this file work? otherwise I can try and get the other DAT file Im just having a bit of trouble accessing it for some reason.

No - that has the wrong name and was not in the correct directory. Which instructions were you following to get it?

Mavic Flight Log Retrieval and Analysis Guide

With the introduction of the Mavic Mini there has been a noticeable uptick in the number of posts requesting help with lost or crashed aircraft. While there is plenty of help and advice available on this forum, and detailed guidance and options on several other websites, I thought that perhaps a...

mavicpilots.com

swadeky · Apr 14, 2020

swadeky said:
Thanks for getting back to me, I am working on getting that DAT file. I found this one and I think its the correct flight. Does this file work? otherwise I can try and get the other DAT file Im just having a bit of trouble accessing it for some reason.

Having trouble finding that flight record, when I go into my MCDatflightrecords folder there is only 1 flight available. Dang, any advice. I found the txt file.

swadeky · Apr 14, 2020

swadeky said:
Having trouble finding that flight record, when I go into my MCDatflightrecords folder there is only 1 flight available. Dang, any advice. I found the txt file.

I am using these instructions: DAT flight log upload instructions for DJI drones | Airdata UAV

Heres a screen shot of what I see on my coputer:

sar104 · Apr 14, 2020

swadeky said:
Having trouble finding that flight record, when I go into my MCDatflightrecords folder there is only 1 flight available. Dang, any advice. I found the txt file.

You already posted the txt log - that was the one I worked from. What is the name of the file that you did find in the MCDatFlightRecords folder?

swadeky · Apr 14, 2020

sar104 said:
You already posted the txt log - that was the one I worked from. What is the name of the file that you did find in the MCDatFlightRecords folder?

The name is 2020-04-14_12-36-12_FLY054.DAT, which I think is just from today. I am reading other threads right now and seeing that other people also have trouble finding flight logs. Dang, haven't yet found a way around this issue. DJI assistant does not read my Mavic air logs either.

sar104 · Apr 14, 2020

swadeky said:
The name is 2020-04-14_12-36-12_FLY054.DAT, which I think is just from today. I am reading other threads right now and seeing that other people also have trouble finding flight logs. Dang, haven't yet found a way around this issue. DJI assistant does not read my Mavic air logs either.

That's odd. And this is the mobile device that you used for the flight in question?

swadeky · Apr 14, 2020

sar104 said:
That's odd. And this is the mobile device that you used for the flight in question?

Yeah its an iPhone7, Apparently this is a common issue and I have yet to see someone resolve it. I am debating deleting and reinstalling the app but I haven't found a fix for this.

Here's one of the many threads: .DAT Files Being Deleted.

swadeky · Apr 14, 2020

Can't seem to find a way around it, I don't suppose you have any wisdom backed speculation on the issue that caused the crash? Thanks again for the help.

sar104 · Apr 14, 2020

swadeky said:
Yeah its an iPhone7, Apparently this is a common issue and I have yet to see someone resolve it. I am debating deleting and reinstalling the app but I haven't found a fix for this.

Here's one of the many threads: .DAT Files Being Deleted.

Yes -the DJI GO 4 app also deletes DAT files when they are synchronized. The main difference is that the GO 4 app doesn't auto-sync, and so it's generally less of a problem. The only resolution is not to sync the files until you have downloaded all the DAT flight records from your device.

swadeky · Apr 14, 2020

sar104 said:
Yes -the DJI GO 4 app also deletes DAT files when they are synchronized. The main difference is that the GO 4 app doesn't auto-sync, and so it's generally less of a problem. The only resolution is not to sync the files until you have downloaded all the DAT flight records from your device.

Copy that, does that mean the .DAT files from my crash have been deleted with no way to retrieve them?

Ill be sure not to auto sync in the future.

sar104 · Apr 14, 2020

swadeky said:
Copy that, does that mean the .DAT files from my crash have been deleted with no way to retrieve them?

Ill be sure not to auto sync in the future.

I don't think there is an auto-sync option on the DJI GO 4 app - did you not sync the records manually?

swadeky · Apr 15, 2020

sar104 said:
I don't think there is an auto-sync option on the DJI GO 4 app - did you not sync the records manually?

Unfortuately yes, I didn't know about the deletion element at the time and thought it better to back up my crash log so i woulnd't lose the data. Ironic really. dang.

sar104 · Apr 15, 2020

swadeky said:
Unfortuately yes, I didn't know about the deletion element at the time and thought it better to back up my crash log so i woulnd't lose the data. Ironic really. dang.

Unfortunately that's not documented anywhere, and so there was no way for you to have known any better.

slup · Apr 16, 2020

And furthermore it's not as consistent for GO4 as it is for the DJI Fly app... I also have a MA with GO4 on 3 Android devices & have never lost a DAT log.

sar104 · Apr 16, 2020

slup said:
And furthermore it's not as consistent for GO4 as it is for the DJI Fly app... I also have a MA with GO4 on 3 Android devices & have never lost a DAT log.

The Android version of the GO 4 app (4.3.32) still doesn't delete DATs on syncing, whereas the iOS version, at least since 4.3.24, now does.

Gerry Mander · Jan 6, 2021

hi peeps, any conclusions as to the issue with the Mavic? Experienced very similar behavior from my 'faultless to date' Mavic Air 1, recently.. similar alarms 'not enough force', went into ATTI mode despite there being 18+ satellites. Flying in the mountains, no man made objects for miles. Pretty scary. Drone dropped 140 feet and was spinning..flew at a severe tilt angle for several seconds. Got it back home, but a bit reluctant to fly again until i resolve the issue. all up to date firmware. acceleromer in IMU showed 'good', not excellent, so with a calibration that was corrected.
Thanks,

rainsipper · Jan 13, 2021

I'm experiencing the same problems today. Flew my Air to a tower 500m away and practised circling. All of the sudden I got:

IMU heading error
Not Enough Force/ESC Error
Strong Interference to Aircraft. Signal interruption may be more likely. Fly with caution.
IMU attitude error. Please check that the IMU is mounted properly.
Attitude is too large., Backwardobstacle sensing is unavailable.
Strong Interference to Aircraft. Signal interruption may be more likely. Fly with caution.

The Air behaved wayward, from the camera I saw it rocked, drifted and losing altitude. Fortunately it was high above ground so it regained balance after a few seconds I pressed RTH and took over control.

My gut feeling is the cell antenna on the tower causing interference but after all it's just a hunch.

Do I have to take it back to DJI for serving? Is it safe to fly it or recalibration would work? The drone was just tested by DJI last money in a routine checkup.