I took my Mavic Air 1 this past weekend out on several successful flights. But one ended with the aircraft suddenly taking off on its own headed toward a lake. Fortunately, it hit a tree instead. It was only at an altitude of about 10 feet and not going too fast. No apparent physical damage was done to it (other than one split in one prop).
However, I'm trying to determine exactly what happened. Before I took off on several of the flights I was asked to recalibrate the compass and/or IMU. Even with the drone and controller sitting on the ground a few inches from each other the controller showed the drone flying at a high altitude and at a far distance. So, something was definitely confused.

I could complete the compass recalibration but never got past the IMU recalibration. However, after restarting the drone while still connected to the controller the drone came up and no longer complained about the IMU. It showed GPS locks and said I could fly. I manually lifted off and got notice that the home point was recorded. So, I went up to about 10 feet and moved it maybe 40-50 feet away from the home. After about a minute I attempted to turn the drone when it suddenly stopped responding and headed throught the trees toward the lake. It was flying of its own will with no input from me.

Today, I've tried to do the IMU recalibration again according to instructions at https://forum.dji.com/forum.php?mod=viewthread&tid=140779&extra=page%3D1%26filter%3Dtypeid%26typeid%3D570%26typeid%3D570
and it never gets past Step 2 where I have the aircraft on its side facing to the right.

I noticed today also, that when I restart the aircraft, the controller connects and shows the IMU is good. It only shows that the compass needs to be recalibrated. After sitting for a couple of minutes, the controller finally says that the IMU too needs to be recalibrated. So, I'm stuck at this point, until I can get the IMU actually calibrated. Is it possible there's a problem on board with a fl do I have a hardware/software issue with something on board?

I extracted my flight logs and it shows that the drone was in P-GPS (Brake) mode the entire time of its very short 1.3 minute flight. The log shows the drone was locked onto 13-14 GPS satellites during the time of its out of control flight.

Any ideas on what I can do or look at next?  I certainly don't want to try and fly it again until I get confirmation that the IMU is actually calibrated properly. I've had this Mavic Air for a little over three years and its always been great. This is the first time it ever crashed.

Since you have the.txt flight log why not post it here or upload it to
https://www.phantomhelp.com/LogViewer/Upload/ and then post the resullting URL here?


It might be worth posting the DAT as well. The DAT, if it exists, should be in the subfolder "MCDATFlightrecord " or some such name. You may need to upload the DAT to a file hosting site and make the page public and post the link here.

Here's the link to the Flight Record: https://www.phantomhelp.com/LogViewer/6JGUJKZLI3LPIAKC3Z83/
Here's a link to the DAT file too: https://www.dropbox.com/s/672w99l6ln3dgrq/2023-05-21_17-36-11_FLY083.DAT?dl=0

gpsguy88 Posted at 5-23 09:40
Here's the link to the Flight Record: https://www.phantomhelp.com/LogViewer/6JGUJKZLI3LPIAKC3Z83/
Here's a link to the DAT file too: https://www.dropbox.com/s/672w99l6ln3dgrq/2023-05-21_17-36-11_FLY083.DAT?dl=0

Hi,

Had a look at your flightlog.
Do you remember wich heading your drone was on the ground before takeoff?

When this fly away started i see some compass heading changes without yaw input.
GPS Speed increasing to approx 7 m/s, but the speed caluclated by the software does show just a fraction of the speed.So not sure about a compass/yaw error wich led to the fly away.

Fly away started at 71.4 seconds in flight (from there distance to HP is changing).In the DAT at 77.7 seconds warnings

• 10894 [L-FDI][FDI] ns atti(1) heading is outlier
• 10895 [L-FDI]NS(0) FUSION(0): fault on . disagree
• 10895 [L-FDI]NS(0) FUSION(1): fault on . disagree
• 10895 [L-FDI]fatal error: no ns with level < 4 !!!
  

Just before crashing into the tree.

Hope you can calibrate the IMU and Compass.

cheers
JJB  [ Charts by FRAP ; the 'best' software for flightlog analysis ]

JJB* Posted at 5-23 23:32
Hi,

Had a look at your flightlog.

Thank you for the detailed analysis! I was able to see some detail on the Airdata site but not to the degree you extracted.

I don't actually recall what heading the drone was facing at takeoff. If I had to guess I'd say it was near NNE.

When I first extracted the log data and saw the software-calculated speed, it felt much slower than what I experienced real-time. So, it's interesting/perplexing to me that it somehow calculated that incorrectly.
I managed to reload the firmware and sitting on my desk inside the house it's not currently complaining about IMU -- even after sitting idle for several minutes. We'll see if that's a fluke or if it's actually 'fixed' now.

But, I may not have a chance to take it outside and try things out until tomorrow.

Hi, gpsguy88. Thank you for reaching out. We are sincerely sorry to read about what happened. Since the drone hit the tree and crashed, we highly recommend that you send your drone back to us for further diagnosis and repair. Data analysis can also be requested (a fee might be applied depending on the warranty). You may submit an online repair request through this link: {https://repair.dji.com/repair/index}. If you need assistance creating a ticket, contact DJI support at (https://www.dji.com/support). Your kind understanding is appreciated and thank you for your continued support.

I managed to calibrate the IMU and compass and fly for a few minutes. But the next day at the same location I was unable to calibrate again. So, I'm not sure what the issue is at this point. I may look into opening a ticket with DJI Support to see how much it may cost to get it fixed. But, I think it's about time to upgrade to a better supported, more recent drone. Thanks everyone for your assistance.

gpsguy88 Posted at 5-30 12:29
I managed to calibrate the IMU and compass and fly for a few minutes. But the next day at the same location I was unable to calibrate again. So, I'm not sure what the issue is at this point. I may look into opening a ticket with DJI Support to see how much it may cost to get it fixed. But, I think it's about time to upgrade to a better supported, more recent drone. Thanks everyone for your assistance.

I would try to change the place of flight for the experiment.