Today i was flying my mavic mini testing the FPV mode. It was working perfectly though with the frequent glitches like aircraft signal interferenece & connection lost issues. It was working fine until my battery was 30 percent and the drone went into RTH mode automatically. I have flown this many times and have seen couple of issues RTH doesnt work properly.

issues found
1) RTH altitude is set but it does not rise to the given altitude set.

The major issue which happened today

2) While return to home suddenly the aircraft started descending though i was not doing anything with the controls even though the RTH altitude as 32 m. The battery was around 27 percent. I was scared and cancelled the RTH and tried to manually fly the drone up. But it was not responding. At one time the drone started responding and i tried to fly manually towards my location but again after sometime the drone started descending. I almost had given up hope and thought the drone was about to crash but luckily was able to land it safely at my home. There was no wind not sure why this major malfunction !!

I believe there are plenty of issues which dji needs to address. Imagine what if the drone crashed somewhere because of their fault. I would have lost my drone forever even though it was not my fault.All my hard earned money would have been gone due to this. . I regret buying this now should have gone for some other ones in the market.

Here is the full video of what went wrong ..

https://youtu.be/TitZ0KapW4k

There was no wind not sure why this major malfunction !!
The problem was unlikely to be a failure of RTH (which is very reliable).
It's much more likely that it's the same uncommanded descent problem that has brought down hundreds of Mavic Minis.
The video won't prove naything though, you'd need to post your flight data to confirm the cause of the issue.

Hi,
  Thanks for your response.. I have uploaded the flight data below..

https://www.phantomhelp.com/logviewer/C2N69VVR7DGV7KFITA4A

anubhab Posted at 4-19 21:29
Hi,
  Thanks for your response.. I have uploaded the flight data below..

That flight data is from a different flight.
https://www.phantomhelp.com/logviewer/C2N69VVR7DGV7KFITA4A/
You flew until 30% and landed without ever using RTH.
I can only see a little minor altitude instability in that one.

Hi,
   My mistake uploaded the wrong one..

Please find the relevant log

https://www.phantomhelp.com/logviewer/D0PAATXV8BI08JHMU86E

Hi anubhab, sorry to hear about the issue with your drone. May we know the firmware version of your drone and the app version? Please upload the relevant log to Dropbox or Google Drive and share the link with us, we'll help you check it. Thanks.

anubhab Posted at 4-19 23:16
Hi,
   My mistake uploaded the wrong one..

Hi,

You are a MM owner #many with a uncontrolled loosing height MM !

When 2 cells are getting < 3.4 volts.....

Mayby it is a good advice, better safe  than sorry,  to fly a MM from 100% to 50% batt level only! Or check batt values during flight and land just before total of 2x 3.4 volts.

Is it possible to upload your DAT file ( FLY018.DAT) for this flight as well ??
I had the same expercience once, so i can check if there is a same error about height control in your DAT as well.

cheers
JJB

Hi Natalia,
   Please find the link below

https://drive.google.com/file/d/1-zxRL-lT5lU6EWEklbSpTntIqXp71QWM/view?usp=drivesdk

Firmware version - 01.00.0400

anubhab Posted at 4-19 23:16
Hi,
   My mistake uploaded the wrong one..

Your Mini flew normally until 12 seconds after RTH started.
You initiated RTH at 12:26.9 at a height of 252 ft.
AT 12:38.1 the mini started sinking in RTH.
It lost 40 feet before you gave it some throttle but the sinking continued.
RTH cancelled at 13:07.1 - still losing height.
At 13:08.3 (106 ft high) you gave it full throttle and took the drone up to 122 ft and the Mini was again holding altitude ... until it started descending again at 13:26.8.

At 13:32.3 and 103 ft it started climbing without corresponding joystick input, climbed to 121 feet and started sinking again at 13:48.8.
At 14:06 it was down to 29 ft and again full throttle had no effect until 14:10 when it started climbing very slowly.
It started sinking again at 14:22.4, again ignoring full throttle from 14:24.8
Signal lost at 14:29 initiated RTh which caused the Mini to climb to 126 feet and come home.
But at 15:29.2 it started losing height again.
Full throttle at 15:55.9 caused a slow climb but a little negative throttle at 16:08.6 started the uncommanded descent again, more positive and full throttle was again ignored.
Low voltage autoland started at 16:07 and the drone continued to the ground.

This drone is 100% unreliable and cannot be trusted in the air.
It is unable to maintain altitude and will continue losing altitude even with full throttle applied.

It is just one of many other Mavic Minis showing this extremely serious problem.
Why doesn't DJI do anything about this months after the problem appeared, with more reports like this coming in each day?

DJI make great drones ... but the Mavic Mini is a certified LEMON.
What a disaster.

DJI Natalia Posted at 4-20 02:24
Hi anubhab, sorry to hear about the issue with your drone. May we know the firmware version of your drone and the app version? Please upload the relevant log to Dropbox or Google Drive and share the link with us, we'll help you check it. Thanks.

DJI have had similar reports every day for months now but still no solution has been announced for this very serious problem.

Is anything being done there or is the problem too difficult to solve?

Thanks for the detailed breakdown.. Thats what happened the drone behaviour was unpredictable..i almost didnt know what to do..this is quite horrifying to be honest..totally unacceptable from dji..am not flying the drone anymore after this..its high risk at the moment..i could have lived with some temporary glitches but this is a major problem..which dji needs to address asap..

Hi,
  I have uploaded the dat file. can you check if you can find something in this.

https://drive.google.com/file/d/108HFvjQLoeek0-SkuyQZC9nDZl3WqkL3/view?usp=drivesdk

JJB* Posted at 4-20 04:37
Hi,

You are a MM owner #many with a uncontrolled loosing height MM !
[Image]

https://drive.google.com/file/d/108HFvjQLoeek0-SkuyQZC9nDZl3WqkL3/view?usp=drivesdk

Here is the dat file. Thanks for your response.

anubhab Posted at 4-20 08:24
https://drive.google.com/file/d/108HFvjQLoeek0-SkuyQZC9nDZl3WqkL3/view?usp=drivesdk

Here is the dat file. Thanks for your response.

Hi anubhab,

ThisDAT file is only 1 kb, don`t you have the FLY018.DAT on your mobile device?

cheers
JJB

JJB* Posted at 4-20 10:35
Hi anubhab,

ThisDAT file is only 1 kb, don`t you have the FLY018.DAT on your mobile device?

Can you tell where i can find this file? in which folder ?

On Android its a sub folder of the FlightRecord folder, called MCDatFlightRecords.

JJB* Posted at 4-20 10:45
On Android its a sub folder of the FlightRecord folder, called MCDatFlightRecords.

Thrs no other dat file apart from the one i uploaded.I thnk it got deleted after it was syncd in the dji fly app.

anubhab Posted at 4-20 10:52
Thrs no other dat file apart from the one i uploaded.I thnk it got deleted after it was syncd in the dji fly app.

bad luck!  

i always transfer both flightlog and dat file to my computer before syncing with DJI.

cheers
JJB

It looks like it's a very common problem, DJI needs to solve it ASAP as clients are losing their patience and trust...

anubhab Posted at 4-20 04:43
Hi Natalia,
   Please find the link below

Hi, thanks for the information. The data that you provided is not the flight data, you are recommended to export the related flight log and let us know the specific time and date when the issue happened.
Flight logs under DJI Assistant 2 for Mavic (https://www.dji.com/mavic-mini/downloads) -- Log Export--Save to local. Please upload to Google Drive or Dropbox and then post the link here.
Sorry again for all the inconvenience caused. I will help to forward the data to the related team for a check.

DJI Natalia Posted at 4-21 04:12
Hi, thanks for the information. The data that you provided is not the flight data, you are recommended to export the related flight log and let us know the specific time and date when the issue happened.
Flight logs under DJI Assistant 2 for Mavic (https://www.dji.com/mavic-mini/downloads) -- Log Export--Save to local. Please upload to Google Drive or Dropbox and then post the link here.
Sorry again for all the inconvenience caused. I will help to forward the data to the related team for a check.

Hi Natalia,
     Please find the link below

https://drive.google.com/file/d/1jz0yAOfDKqg5K6D0ItsaAgNHDuVu-vuV/view?usp=sharing

Please check the data for 2020/04/20  06-39-59

anubhab Posted at 4-21 07:27
Hi Natalia,
     Please find the link below

Thanks for the information, I will help you download it and then forward it to the related team for a check.

DJI Natalia Posted at 4-22 04:47
Thanks for the information, I will help you download it and then forward it to the related team for a check.

Hi,
   I have already uploaded.Let me know if you need anything else.

anubhab Posted at 4-24 02:36
Hi,
   I have already uploaded.Let me know if you need anything else.

Thank you, anubhab. It has been forwarded to the related team, if there is an update, we'll let you know.

DJI Natalia Posted at 4-26 00:47
Thank you, anubhab. It has been forwarded to the related team, if there is an update, we'll let you know.

Any update on this? I am not flying this drone dont knw if it happens again and i lose it. Waiting for ur update.

anubhab Posted at 5-18 23:58
Any update on this? I am not flying this drone dont knw if it happens again and i lose it. Waiting for ur update.

Hi anubhab, sorry to have kept you waiting. I'll push the related team again and get back to you soon.

anubhab Posted at 5-18 23:58
Any update on this? I am not flying this drone dont knw if it happens again and i lose it. Waiting for ur update.

Hi anubhab, sorry to have kept you waiting. Our team has checked your data, you are recommended to change a new set propeller;
By the way, please make sure the firmware has been updated to the latest and choose an open area where there is no magnetic interference to fly the drone.

you set the RTH settings to return to home at current altitude

DJI Natalia Posted at 5-21 01:58
Hi anubhab, sorry to have kept you waiting. Our team has checked your data, you are recommended to change a new set propeller;
By the way, please make sure the firmware has been updated to the latest and choose an open area where there is no magnetic interference to fly the drone.

Thanks for the update and i will try the recommendation. But the thing is
1.why RTH failed?
2.why the controls were not working?