Mavic mini uncontrolled spin and crash

[miker570]

After 39 great flights, after a short flight today my MM spun out of control and crashed into a tree directly below it.
It took off from my home fine, all systems checked out, home point was set and I flew up to about 80 feet and started flying towards the lake. I was going to check out the ice fishing activity on the lake. As it approached the lake I heard a strange sound, like feathers ruffling, so I stopped and observed it was flying ok. I turned around and flew back overhead and listed for anything unusual. It sounded normal so I headed back to the lake over the tree line on the shore. All seemed normal then it suddenly started to descend and started spinning out of control. It hit a tree directly below it and broke the right front landing leg and the gimbal came loose breaking one of the electrical connections. This was my first DJI drone. I have been flying the cheap little toy drones for a few years to practice my fly by sight skills. Very disappointed it hit the tree, if it reached the lake it would have crashed into the snow with probably less damage. I have DJI care so I’ll need to report the crash to them soon.

This is the link to the video of the crash. I have the DAT file but I’m unable to upload it at the moment.

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[old man mavic]

there is one thing that springs to mind,and that is ice forming on the props,it looks very overcast and cold in the video and also very still combine that with the fact that as the props spin,the air passing over them speeds up on the top surface to provide lift ,and with the right conditions in place ice can form and change the airflow over the prop resulting in a sudden loss of lift from the prop and may have been the difference in the sound you heard, this is just a theory and probably a long shot ,im sure once you have got the logs all will be revealed

 

[miker570]

It was only outside less than 5 minutes when the crash occurred. The props were intact, but dinged up from hitting the tree branches. I opened a case with DJI care and already received a UPS return label. They didn’t provide any shipping instructions.
Does any know if your return everything in the box, RC and everything or just the MM? I send an email to DJI support asking the same question but no answer yet.

 

[miker570]

Here is the DAT file
View attachment DJIFlightRecord_2019-12-07_[13-34-58].txt

 

[Thomas B]

It was only outside less than 5 minutes when the crash occurred. The props were intact, but dinged up from hitting the tree branches. I opened a case with DJI care and already received a UPS return label. They didn’t provide any shipping instructions.
Does any know if your return everything in the box, RC and everything or just the MM? I send an email to DJI support asking the same question but no answer yet.

Likely they’ll only want the drone, and in it’s original box... my experience anyway... they sent me an email with instructions. Check your spam box. They also registered the new drone for me before shipping.

 

[WobblingWillie]

The rated min operating temp for the Mini is 32F. The Mavic 2 has a min operating temp of 14F. This may be one of the reasons that the Mini has a higher min temp.

 

[miker570]

The temp was above 32F and very light breeze. I have flown many times when it was much colder without and problem at all.

 

[old man mavic]

The temp was above 32F and very light breeze. I have flown many times when it was much colder without and problem at all.

no problem, it was just a suggestion to explain what could have happened

 

[miker570]

Much appreciated to all for your comments and ideas. Hopefully the DAT file will reveal the cause of the failure.

 

[DanMan32]

I would hold off a bit until the experts review the log. You don't want to waste a refresh over a warranty issue and you may need a convincing argument.

 

[Gryphon962]

there is one thing that springs to mind,and that is ice forming on the props,it looks very overcast and cold in the video and also very still combine that with the fact that as the props spin,the air passing over them speeds up on the top surface to provide lift ,and with the right conditions in place ice can form and change the airflow over the prop resulting in a sudden loss of lift from the prop and may have been the difference in the sound you heard, this is just a theory and probably a long shot ,im sure once you have got the logs all will be revealed

No. The only way that ice would form on the props was if it was flying in freezing rain. I dont think this is the case.

The DAT file will reveal what the motors and props were doing.

 

[Gryphon962]

Here is the DAT file
View attachment 87559

Thats the txt file. The DAT file is in another folder, and has more info on what the motors and props were doing. Please try again....

 

[miker570]

Ok I had to zip it up. I think it’s small enough to attach now.

View attachment 2019-12-07_13-43-49_FLY075.zip

 

[pmshop]

Pardon the side track but where are you all finding the .dat files on the MM?
I have iPasOS 13.2.3 and when I download the FlightRecords folder, it has a MCDatFlightRecords folder...but it is empty after every download.

*UPDATE* Sorry but I just checked that folder one more time and my last flight finally generated a .dat file.
First .dat file on over 15 flights.

 

[allenface]

there is one thing that springs to mind,and that is ice forming on the props,it looks very overcast and cold in the video and also very still combine that with the fact that as the props spin,the air passing over them speeds up on the top surface to provide lift ,and with the right conditions in place ice can form and change the airflow over the prop resulting in a sudden loss of lift from the prop and may have been the difference in the sound you heard, this is just a theory and probably a long shot ,im sure once you have got the logs all will be revealed

Those of us in the south aren’t subject to icing, but I like that notion. Well, I don’t like it but I like the plausibility.

 

[OldGuy]

I may be wrong but to me it looked like you just clipped the upper branch of the tree!?

 

[Fly Dawg]

@miker570 The spin began just as you released the elevator at ~119 seconds. The .dat you supplied above is not the correct file. You need FLY074 for this flight.

 

[crlmjohnson]

tree...

 

[miker570]

I’m sure the weather or temp was not a factor, it was about 34F and I had just stepped outside from being in the home. The flight lasted 1 minute and 30 seconds. I had visual contact with my MM and was over the tree tops by a few feet. There is a chance there was a twig sticking up I didn’t see but always set my RTH at 80+ feet and never had an issue with many flights. Note that I am launching from a table on my 2nd level deck that adds 10+ feet from the ground. After syncing my logs for my DJI Care case, I do not see the DAT files anymore. I had copied the 075 DAT to my iCloud Drive, and I still have that. I don’t see any DAT files under the DJI data folders now. I can still replay the flight so the data must be there somewhere. Here’s a link to a video screen capture of replaying this flight.
Thanks for your assistance.

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[Thomas B]

Difficult to judge, but all the error message appeared as you approached what appears to be a taller tree on the second outbound leg of the flight. Logs likely would be definitive.