Hi Guys,

I am a new to this things and i have to say that i am having a lot of fun with this little boy, so glad i joined the group

As a beginner i am facing a massive learning curve and i believe i need some help with the issue i am currently trying to understand.

I've used the search function but i found nothing similar to my issue ( maybe it's my fault as i am a rookie.......sorry )

Yesterday i took this little aggressive boy for a ride and i had a bit of an issue which i am trying to understand if it was a human error, a device error or a well known behavior of the device. Basically despite the wind I've had no issue for the whole flyght till the last 5 minutes.
In the middle of the flight i switch to sport mode, then with 20% of battery left i sent the drone at pretty much 150 meters from me, then plan was to rotate it of 180 degrees and come back, but something didn't work. I managed to rotate itself but when i tried to move it forward it didn't move at all. I could go left right, up and down and rotare but no way i could go back or forward. After a couple of seconds it started telling me that the battery was about to die so i clicked confirm to return home automatically but there was strong wind so it didn't move at all. I licterally landed it where it was then the battery died and i went to pick it up.
I've checked the map ( before the flight ) and i wasn't definitely in a no fly zone.


I swithed it off, i took it home i changed battery and i did a fly test in the garden and it was perfect.

I watched the video of the flight in the map and i enabled the joystick icon ( or whatsoever is called ) so i could see the commands.
When i started Having problems it was clearly not taking the forward input ( the direction bar didn't turn blue at all ).


This is the description of the issue and i'd really like to go deeper and understand what happened, do you guys have any idea ? Maybe the strong wind in combination with low battery ?


P.s.
I am assuming that this device must have some sort of black box with flight logs but i don't really know how to extract the data and how to read them

Sounds like when you where trying to move the sticks your drone
had already kick into RTH. Also check your RTH settings to make sure
it's set to RTH and not land. It's not wise to send your bird your on a
long ride when the battery is that low. Although the wind may not be blowing
that hard ground level, it's a different story at 100ft up especially with the mini.

You can't fly forwards or back with return to home activated. Also be careful flying in high winds. If the wind is stronger than the drone can physically fly, you won't get it back.

I am assuming that this device must have some sort of black box with flight logs but i don't really know how to extract the data and how to read them
This is correct and making guesses without seeing the data is likely to be wrong.
To get to your flight data, go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report
For help interpreting the data you can post a link for the report here.
Or just post the .txt file.

I suggest you follow Labroides' advice and get familiar with at least one of the flight analysis sites available. That will be of immense value with no real cost.

Hi guys thanks for your valuable reply

Here is the link of the logs

https://www.phantomhelp.com/LogViewer/765Y4ZDK2IZO2PYBOEM2

I've started having problems pretty much at 18' and 10''

What do you think ?

I'm not the best at this and you should wait for more experienced members. But it looks like there was just too much wind and it was probably a mistake to increase altitude after it went badly. You should have seen the high wind messages that started at 1m10s and continued until 12m 33s.

"Vento  molto forte, impossibile attivare il ritorno automatico. Scendere di  quota immediatamente e ritornare al punto di partenza manualmente."

i'd really like to go deeper and understand what happened, do you guys have any idea ?
I searched your data for the few times when you left the drone hovering to get an idea of what the wind was doing by checking the drone's flight data at those times.

The wind was gusty, from north of west and close to 8 metres/sec up at 20-50 metres high with the Mini" pitch, roll and velocity data indicates that the wind is only just able to hold position.
Around 16:08 44 metres up with full stick in Sport Mode and pitching up to 25° the Mini could only make 3 m/sec trying to fly into the wind but being set off course toward the SE.
But around 18:03 40 metres up and heading east (with the wind behind it) it could easily fly at 12 m/s with full stick and only light pitch forwards.

You initiated RTH at 19:02.7 and found the Mini (39 metres up) was being blown backwards, further away from home.
You cancelled RTH and tried Sport Mode (but still 35 metres up) and found you still weren't making progress and the Mini was going backwards at up to 4 m/s in gusts.

Eventually you brought it down to 22 metres where it still wasn't making headway, but was being blown away at a slower pace.
Then (stupidly) took it up to 78 metres where it continued being blown away even faster.
At 21:33 with the battery running low, autolanding commenced.

The data shows the drone continuing to be blown away even though you gave it full right stick during the descent.
It didn't start to make (slow) headway until below 32 metres.

Lessons from this incident?
The Mini is a slow drone and not equipped to fight strong winds.
The wind is usually stronger up higher and going higher makes a headwind problem even worse.
If fighting against a headwind, get down low out of the strongest wind straight away.

More importantly, think ahead and avoid getting caught in that situation, because once you are fighting a headwind problem it might already be too late.
You need to be conscious of the direction of the wind even more than the strength.
Fly away slowly into the wind and you have an easy flight home with the wind behind the drone.
Try doing that the other way and it's easy to lose the drone.

Hi. Thank you for creating this post and welcome to the DJI Forum. I am sorry to know about your previous flight. To ensure a safe flight, it would be best to please follow our official DJI Safety Guidelines for the DJI Mavic Mini. Thank you.

  10#

I searched your data for the few times when you left the drone hovering to get an idea of what the wind was doing by checking the drone's flight data at those times.

How did you do this ?

The wind was gusty, from north of west and close to 8 metres/sec up at 20-50 metres high with the Mini" pitch, roll and velocity data indicates that the wind is only just able to hold position.
Around 16:08 44 metres up with full stick in Sport Mode and pitching up to 25° the Mini could only make 3 m/sec trying to fly into the wind but being set off course toward the SE.
But around 18:03 40 metres up and heading east (with the wind behind it) it could easily fly at 12 m/s with full stick and only light pitch forwards.

By pitch do you mean the angle of inclination of the device ? Would it be the circle above the back / forward stick on the map i linked ?

You initiated RTH at 19:02.7 and found the Mini (39 metres up) was being blown backwards, further away from home.
You cancelled RTH and tried Sport Mode (but still 35 metres up) and found you still weren't making progress and the Mini was going backwards at up to 4 m/s in gusts.

Eventually you brought it down to 22 metres where it still wasn't making headway, but was being blown away at a slower pace.
Then (stupidly) took it up to 78 metres where it continued being blown away even faster.

Agree but panic makes you do silly things

At 21:33 with the battery running low, autolanding commenced.

The data shows the drone continuing to be blown away even though you gave it full right stick during the descent.
It didn't start to make (slow) headway until below 32 metres.

Lessons from this incident?
The Mini is a slow drone and not equipped to fight strong winds.
The wind is usually stronger up higher and going higher makes a headwind problem even worse.
If fighting against a headwind, get down low out of the strongest wind straight away.

More importantly, think ahead and avoid getting caught in that situation, because once you are fighting a headwind problem it might already be too late.
You need to be conscious of the direction of the wind even more than the strength.
Fly away slowly into the wind and you have an easy flight home with the wind behind the drone.
Try doing that the other way and it's easy to lose the drone.

How on earth did you manage to find out all of this from that tabel ?

A MASSIVE THANK YOU for your ( all of you ) support, now i clearly understand it was human error. Is there anything i can do to understand if the drone got permanently damaged after this experience ?

"How did you do this ?"

There is far more data available than is shown on the analysis web sites after uploading your file. Those sites allow you to download the original file as well as some reports with other important data. Add that to the expert capabilities of one of the best analysts here (cue L...) and you can have a mountain of information.

GaryDoug Posted at 8-27 19:43
"How did you do this ?"

There is far more data available than is shown on the analysis web sites after uploading your file. Those sites allow you to download the original file as well as some reports with other important data. Add that to the expert capabilities of one of the best analysts here (cue L...) and you can have a mountain of information.

I see thanks to all of you guys

Compimenti per il nickname

Conte Mascetti Posted at 8-27 13:26
10#

I searched your data for the few times when you left the drone hovering to get an idea of what the wind was doing by checking the drone's flight data at those times.

Hi,

"How did you do this?"

check this > https://forum.dji.com/thread-203659-1-1.html  [ soon an update ]

cheers
JJB

The Mavic Mini withstands winds of up to 7.9m/s or 28km/h above avoiding flying.
I advise you to download the UAV forecast app. And to use it before a flight it tells you the weather, wind speed and gusts, GPS satellites, solar activity (Kp), no-fly zones.
Fly in peace

Renato61 Posted at 8-30 22:31
Compimenti per il nickname

Thanks bud. Glad to see we come from all over the world here

JJB* Posted at 8-30 23:59
Hi,

"How did you do this?"

You've done a great work here. Good stuff. Thanks bud

Conte Mascetti Posted at 9-1 13:36
You've done a great work here. Good stuff. Thanks bud

Hi Conte,

I always save my flightlogs and DAT files after a day`s flying, before syncing with DJI.
Always use a screen recording  for each flight (i use DU recorder).

So in FRAP analyse your flights, easy way to get an understanding of it all.

AND most important ; check your drone compass in the app before each take-off.
If compass shows a different heading than the actual heading ; don`t fly!

Happy many landings,
Cheers
JJB

Labroides Posted at 8-26 20:41
i'd really like to go deeper and understand what happened, do you guys have any idea ?
I searched your data for the few times when you left the drone hovering to get an idea of what the wind was doing by checking the drone's flight data at those times.

Very much agree to that the wind conditions in this flight was very close to what a Mini can withstand ... also that the pilot wasn't aware of the risks & didn't do much to mitigate them.

But one big contributing factor is so far missed out in the analysis ... this Mini don't perform according to spec. tilt angle wise. This will lower the Mini's already low speed further more & degrade it's ability to fight the wind.

Even though no uncommanded descent had evolved it was very close ... every thing performed reasonably according to the Mini's spec until the end of the first Sport mode session, just before RTH was commanded.

Suddenly the Mini can't tilt according to the specified 30 degrees it should be able to do in Sport mode ... the most it could achieve was around 15 degrees.

Looking into the period just before RTH where we have a 13sec long full elevator (light green) with headwind. The tilt angle (magenta) goes just to 15 degrees in average. This severely minimize the Mini's speed (dark blue). By this the Mini's ability to make a heading speed into the wind have been severely crippled.

  

This low tilt angle is then maintained throughout the rest of the flight ... easy to see here on the overview from start flying in Sport mode until landing ... the magenta graph shows a real difference & settle in on a much lower value.



Besides all the other lessons learned I also recommend a prop change as this bad ability to tilt certainly is due to deformed rear props making the motors rev to max.

slup Posted at 9-2 04:31
Very much agree to that the wind conditions in this flight was very close to what a Mini can withstand ... also that the pilot wasn't aware of the risks & didn't do much to mitigate them.

But one big contributing factor is so far missed out in the analysis ... this Mini don't perform according to spec. tilt angle wise. This will lower the Mini's already low speed further more & degrade it's ability to fight the wind.

So true!

All MM uncontrolled descents flights have the same patern, fluctuating pitch roll angles at lower values.


See the whole flight in my chart, easy to see where this MM goes into some kind of an error.

cheers
JJB

I will definitely replace them thanks guys

I highly recommend that you download the .txt and .DAT from your phone after every day of flying.  In the DJI fly app, under Profile > Settings > Sync Flight Data, make sure that is turned OFF.  If you leave that on, the .DAT file will sync with DJI and then be deleted from your phone.  What I do is download the .txt and .DAT files to my computer and THEN turn the Sync Flight Data back on.  Among other then that accomplishes is that it updates the flight distance shown here in the forum.  On my controller is a P-Touch label to remind me to turn OFF the Sync Flight Data before I fly.  The .txt files will stay on your phone (forever as far as I know), but the .DAT files are deleted after syncing.  The .DAT files contain FAR more information.  As previously mentioned in this thread, there are several on-line analysis sites.  Locally you can use CsvView.  I don't do a detailed analysis of every flight, but I generally do look the .DAT file for most flights - especially if there is something odd that happened.  High wind warning during the flight is one that will generally get me to look at it the data file in order to see what the wind really was doing.  There is a HUGE amount of data saved.
And, as a beginner, don't be flying off somewhere with 20% battery.