Help! Mini Midair FreeFall (Video and Logs posted)

JohnNokomis · Aug 28, 2020

I've been having issues with the gimbal glitching randomly since the day I started flying the mini. But this ones takes the cake, watching that as it happened I thought I was watching the bird tumble to the ground. I was on my way back after maybe a 15 minute flight. Any help would be amazing. I was flying with the Litchi Beta for majority of this flight, but had switched over to the stock DJI Fly app when this happened. That is also why the flight data is split into two logs.

Thank you for taking the time to look at this issue.

LOGS-

Starz · Aug 28, 2020

Interesting. Any particular reason that the mini wasn’t sent back when you first noticed the problem?

JohnNokomis · Aug 28, 2020

Because it's just a quick jerk to the left and back normally, lasting a second at most. At first it was only once a flight at most but it's become more frequent. I'm not sure this freefall is related because it's never been like this until last night.

Starz · Aug 28, 2020

Purchased new?

JohnNokomis · Aug 28, 2020

Yep brand new from Amazon May 13, 2020.

slup · Aug 28, 2020

JohnNokomis said:
I've been having issues with the gimbal glitching randomly since the day I started flying the mini. But this ones takes the cake, watching that as it happened I thought I was watching the bird tumble to the ground. I was on my way back after maybe a 15 minute flight. Any help would be amazing. I was flying with the Litchi Beta for majority of this flight, but had switched over to the stock DJI Fly app when this happened. That is also why the flight data is split into two logs.

Thank you for taking the time to look at this issue.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

LOGS-

Mmm ... understand your feeling of a Mini that are free falling, but it didn't. Looking into the DJI FLY log it actually was rather rock solid when it comes to height keeping & following your throttle commands. Can add that the winds up there at 175m was up to the Mini's limit ... 8,4m/s headwind.

But something happens uncommanded at 793sec ... the AC starts to pitch, roll & yaw abrupt without stick inputs. Here below the changes in the 3 AC motion axis + the active stick inputs (click on the chart to make it larger).

Adding to all the AC movement ... below the movements of the gimbal from the same time.

If you still have the mobile device .DAT log left, post it up ... maybe something there can explain this. The correct .DAT log ends with FLY005.DAT.

JohnNokomis · Aug 28, 2020

Thank you very much for the insight.
I have a dedicated LG V30+ that I use to fly with. It's at home but I will post it when I get there here soon.

boblui · Aug 29, 2020

The Mini is well know for it's uncommanded actions, first, it was the descent, then came yawing and now twitching ?

Starz · Aug 29, 2020

Looks to be a bit more than a twitch.

boblui · Aug 29, 2020

A seizure ?

JAW · Aug 29, 2020

With my M2Z I've encountered stability problems when switching between Litchi and Go4----whichever program I've switced FROM still remains in memory. That's using a CrystalSky monitor. Don't know if it's an issue with the MINI.

Dave Maine · Aug 29, 2020

There have been persistent problems with having 2 drone control tablet software packages active at the same time. Without better cases to diagnose what is actually happening, the solution that seems to work is to completely stop the app you don’t plan to use. This is not just closing the app, but stopping it’s background processes itself. On the Apple devices, it is done by displaying all the processes running by quickly double clicking on the home button, and then swiping up on the active processes.

JohnNokomis · Aug 29, 2020

Maybe I'm missing something, but I can't find the Fly logs you're talking about. I can find plenty of logs within the DJI folder but they're all named by date, not Fly005.dat. Isn't that the log that automatically syncs off the Android device anyways?

As far as closing apps, I know you need to close apps when switching and I did. I hit the square button on the bottom right of the device (recent apps) and closed litchi before opening DJI Fly. I make sure the remote control app is the ONLY app running period. Also 99% of the time I have it in airplane mode. Hence why I have a dedicated device to fly with.

slup · Aug 29, 2020

JohnNokomis said:
...can't find the Fly logs you're talking about. I can find plenty of logs within the DJI folder but they're all named by date, not Fly005.dat. Isn't that the log that automatically syncs off the Android device anyways?

If you've had auto sync active & the subfolder MCDatFlightRecords, in the folder that contains the TXT logs is missing the log ending with FLY005.DAT ... it's gone I'm afraid.

JohnNokomis · Aug 29, 2020

I've exported the near half-gigabite log file off the AC itself using DJI Assistant 2. But from what I have read this is useless because of encryption? Why in the world would DJI keep me from seeing my own flight logs? I feel like it would tell us more about this issue since it would take the RC out of the equation.

slup · Aug 29, 2020

Perhaps this can be a possibility ... try to retrieve it & post it up, have never tried to read one of those, could be interesting.

JohnNokomis · Aug 29, 2020

Maybe this is the file you're talking about. It was exported using DJI Assistant 2 as well, so encryption may be an issue. I don't know how to tell. The 479MB DAT file is uploading to Google Drive right now.

FLY005.DAT

AC LOG File-
EXPORT_FILE_2020-08-27_22-57-36.DAT

Thank you so much for your analysis

slup · Aug 29, 2020

JohnNokomis said:
Maybe this is the file you're talking about. It was exported using DJI Assistant 2 as well, so encryption may be an issue. I don't know how to tell. The 479MB DAT file is uploading to Google Drive right now.

FLY005.DAT

AC LOG File-
EXPORT_FILE_2020-08-27_22-57-36.DAT

Thank you so much for your analysis

All logs coming through DJI Assistant 2 from the AC will not be readable by others than DJI unfortunately ... did you check the SD-card in the AC after the log called fc_log.log ?

Starz · Aug 29, 2020

Based on the previous posts, can this issue not be replicated?
OP mentioned that this has been a persistent issue to some degree.

JohnNokomis · Aug 30, 2020

Oh it was replicated alright. Today I flew the Mini for the first time since this took place, and the issue is still there. It did it not just once, but TWICE. This time I was using my iPad, so it isn't RC related. The second flight only has the "normal" gimbal glitching but I'm using the stock DJI Fly app on Andriod. I was trying to get the AC to replicate what it did before. I also have the log file off the SD card this time (it was formatted before I knew about saving it last time). Someone please tell me what is going on, because I can no longer trust my AC.

LOG-
FC LOG off SD Card