Hi,

I am Linh from Vietnam.

I lost control of my drone during flying on a lake then i went down the water.

I had 4-5 shots of videos before the last one the drone flew down in front of me and I couldn't catch it. The drone was sunk.

Could you please help me to track? I asked a local Vietnam shop to report few days ago (5 May 2021), but no response. Then I just sent an email to support@dji.com. And I also send here again my case.

This is a link to download the flight log: https://www.dropbox.com/s/ytwle407sr45mzb/3u%20Files.rar?dl=0

Thank & regards,

Linh

I don't see any files from 5-5. What date is the file you are asking about? Was it 5-1?

Nevermind. Your download is way too large. Try to post just the file you want analysed.

Hello there Linh. I am sorry to know what happened to your DJI Mavic Mini and thank you for reaching out. It is good to know that you have already contacted our DJI support through email. Rest assured that once our DJI support team will be sending you notifications and instructions with regards to this matter.  Again, I am sorry and thank you.

Hi Linh,

Do you know that you published all your flights and other data??

oke, last flight on 2 may 2021 ; many NotEnoughForce in the log, did you had the blades quard fitted ??
msg " Propeller guards detected" in the log.

But that was not the problem, at 1m21s in flight your compass changed heading from 185 to 250, this without a RC input mady by you (so no manual yaw input)

This compass value change is the start of your fly-away, not for long period as the max power was reached and your mini descended quickly.

Question is why after 1m21s the compass value did change??

Personally i do not believe that your compass was disturbed at start of the flight, as you made some yaw inputs in flight wich most of the times is a trigger to change comapss value if compass was faulty at start. But it is possible as your yaw inputs where minor...

Do you know wich heading your mini was on the ground before take-off ??
Take-off from the yellow boat?  deck not only wood ?
Lovely scenery in your country!

PS in your DAT file a error : " FAULT ON . MAGN_HEADING_ERR_LARGE", so compass error cause of the fly-away.

cheers
JJB

JJB* Posted at 5-10 22:50
Hi Linh,

Do you know that you published all your flights and other data??

Thanks JJB for your analysis. In spite that I don't really understand the technical matters you texted, I believe that the drone was no problem before the flight because I had 3 previous shot in good view. There are two boats and yes I was standing on the yellow boat and started the drone on the top of the boat.

The flight log I asked my local shop to teamview and got it. I don't know what is inside the rar file.

DJI support replied my case that they are judging.

Thanks again JJB

Linh Thoai Ong Posted at 5-11 07:50
Thanks JJB for your analysis. In spite that I don't really understand the technical matters you texted, I believe that the drone was no problem before the flight because I had 3 previous shot in good view. There are two boats and yes I was standing on the yellow boat and started the drone on the top of the boat.

The flight log I asked my local shop to teamview and got it. I don't know what is inside the rar file.

Hi Linh,

oke, the rar file has all flightlogs, dats  and some video`s files in it.
Not really personal, so up to you to leave it online or remove the link to the rar.

I saw you standing on the top of the yellow boat  ;-)Did you had the mini on the deck as starting point or was is a hand-takeoff?

In previous flights many errors about max power reached, propellers spinning too fast etc etc.

Hope that DJI will come with a good answer (and help you out)  why this has happend to your mini.

cheers
JJB

JJB* Posted at 5-11 10:33
Hi Linh,

oke, the rar file has all flightlogs, dats  and some video`s files in it.

I put the drone on a flat board to take off. It seems that propellers too fast happened many times before, but all was okay.

Linh Thoai Ong Posted at 5-11 19:54
I put the drone on a flat board to take off. It seems that propellers too fast happened many times before, but all was okay.

if the flat board was the top deck of the yellow boat and was (part) from iron....that made the compass goes offset and in flight back to normal ; fly away.

JJB* Posted at 5-11 22:46
if the flat board was the top deck of the yellow boat and was (part) from iron....that made the compass goes offset and in flight back to normal ; fly away.

I don't know what materials the flat board is made from. I have a question why other previous 3 shot were okay?

Linh Thoai Ong Posted at 5-11 23:41
I don't know what materials the flat board is made from. I have a question why other previous 3 shot were okay?

Hi Linh,

Many errors in flightlog 21 april 08:32 ;

16x ; "Aircraft max power load reached. Decrease altitude and fly with caution. If this issue persists, Land immediately"
1x ;  "Propeller(s) rotating too fast. 120984Propeller rotating too fast. Wind resistance affected. Return to home and land promptly"
Many errors in flightlog 21 april 08:43 ;

Takeoff with no GPS signals, thus ATTI mode.
17x ; "Extra payload detected. Return aircraft to an area nearby the home point promptly and fly in a wind-free environment to ensure flight safety"

Flightlog 2 May 17:06 ; no landing in this log....what happend?

Flightlog 2 May 17:08 ; normal flight without errors.

Answer to your question ; in many of your logs i see errors, about max power reached, or propeller to fast, or take off with no GPS > ATTI mode
Only the last compass error was a major error in resulting loss of craft, could have happend earlier to your MINI due to other errors, ignoring 16 errors is not wise to do!

cheers
JJB

JJB* Posted at 5-12 03:49
Hi Linh,

Many errors in flightlog 21 april 08:32 ;

Hi JJB,

Can you advise me what I should do if the propeller too fast or in case no GPS in order that I can have experience in the future?

Thanks

Linh

Don't use a prop guard outdoors. What model prop guard was used? Perhaps it was too heavy? Were there any other extra attachments to the drone....gimbal guard, top mounts, strobe lights, etc. Were the props standard DJI parts? Any nicks on them?

Wait for good GPS coverage before launching.

Carry a tiny magnet to test for ferrous metals on the launch surface.

GaryDoug Posted at 5-12 19:03
Don't use a prop guard outdoors. What model prop guard was used? Perhaps it was too heavy? Were there any other extra attachments to the drone....gimbal guard, top mounts, strobe lights, etc. Were the props standard DJI parts? Any nicks on them?

Wait for good GPS coverage before launching.

Hi GaryDoug,

Thanks for your clarification.

I didn’t use any guard and attachments except the drone itself since I started to fly from the first day. I know that sometimes the screen notified that the propellers too fast but after few seconds/minutes it was okay so I thought I didn’t need to check it out or bring it to a local shop for a check and even the manual didn’t tell if I should check something if such notification happens.

Regards,
Linh

Linh Thoai Ong Posted at 5-12 20:00
Hi GaryDoug,

Thanks for your clarification.

Bending the propeller(s) during storage will cause propeller rotating too fast error. Running shape of propeller will cause aircraft crash.

I found some suggestion is advise to change new propeller and don't keep propeller bend in storage box.

siowxsen Posted at 5-12 21:39
Bending the propeller(s) during storage will cause propeller rotating too fast error. Running shape of propeller will cause aircraft crash.

I found some suggestion is advise to change new propeller and don't keep propeller bend in storage box.

Hi Siowxsen,

Thanks for your help. I learn one more new knowledge about the propeller storage. However, I’m sure that my drone propellers did not have any bend.

Linh Thoai Ong Posted at 5-12 22:10
Hi Siowxsen,

Thanks for your help. I learn one more new knowledge about the propeller storage. However, I’m sure that my drone propellers did not have any bend.

Welcome.

I see, hope DJI will advise you the further action or solution.  Remember to share with us the outcome later. Thanks

siowxsen Posted at 5-12 23:00
Welcome.

I see, hope DJI will advise you the further action or solution.  Remember to share with us the outcome later. Thanks

Sure, I will

Linh Thoai Ong Posted at 5-12 18:40
Hi JJB,

Can you advise me what I should do if the propeller too fast or in case no GPS in order that I can have experience in the future?

Hi Linh,

Others have already given you advice.

Mini1 is an underpowerd drone, so if you can buy a Mini2.

Use the protection box to keep blades when drone folded in good shape (see > https://forum.dji.com/forum.php?mod=viewthread&tid=242151)
Learn more about how to use a drone, what is the effect of no GPS and how to deal and check your compass before take-off **


Don`t continue to fly if you see serious warnings in the app.....

PS Mini2 does not have the max power reached or propeller to fast, flying in normal conditions ofcourse.

** compass check before take-off is THE most important check for DJI drones!

cheers
JJB

Linh Thoai Ong Posted at 5-12 20:00
Hi GaryDoug,

Thanks for your clarification.

Ignore the following. I see you have already made that available. We will take a look for you.




It may help if you can post the .dat file here. It can be found in the DJI/dji.go.v5/FlightRecord/MCDatFlightRecords folder on your phone....if you have not synced with DJI. If you have synced, it will not be there. That file will show all 4 motor speeds during the flight.

After viewing your dat file, it appears that all 4 motors are running far above average, with the left rear being the worst and occasionally going over 15,000 rpm. Here is a comparison with one of my files (top image with a 10 gram load attached) from last year. Notice that yours (bottom image) is averaging about 12,000 rpm with mine averaging about 9,500 rpm even with the load attached. Something was loading your drone down or perhaps this is just the effects of having bad compass performance.

Note: Mine is over a longer period of time and so looks "busier".

Hello friends,

I am glad to inform that I had received a new set of flight as a compensation for warranty including one flycam and one battery. In fact, I had a positive response from the DJI local agency few weeks after the claim, however, due to the covid-19 time seriously in Saigon, so I just got the flycam a week ago after 6 months lost.

Thank you very much for sharing your knowledge in my case.

Best,

Linh from Vietnam

Linh Thoai Ong Posted at 11-27 04:30
Hello friends,

I am glad to inform that I had received a new set of flight as a compensation for warranty including one flycam and one battery. In fact, I had a positive response from the DJI local agency few weeks after the claim, however, due to the covid-19 time seriously in Saigon, so I just got the flycam a week ago after 6 months lost.

Hi Linh,

Many happy landings with your replacement!

cheers
JJB

Thanks, JJB

Linh, delete the irrelevant flights from that drop box or, if possible, make all but the relevant flight private, it look like you a lot of readable logs there

Sean-bumble-bee Posted at 11-27 04:44
Linh, delete the irrelevant flights from that drop box or, if possible, make all but the relevant flight private, it look like you a lot of readable logs there

Thanks, Jean. I unshared.