Hello from Australia

[Legendberry]

....I've been searching for answers to an uncontrolled descent issue with my mini after 400 flights and I think Ive come to the right place with the flight data analysts... here's the video of my near catastrophic flight with the airdata link in the comments

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After that I didn't change props or firmware just 2 weeks of flogging around just not far over water and can't get the error message back so now its back with DJI who recommended I send it to them.
It would be good to have an understanding of the issue to better manage the risks and good to know how DJI responds to those that may not have been lucky enough to be retreived

 

[Mavic Pro Platinum]

....I've been searching for answers to an uncontrolled descent issue with my mini after 400 flights and I think Ive come to the right place with the flight data analysts... here's the video of my near catastrophic flight with the airdata link in the comments

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After that I didn't change props or firmware just 2 weeks of flogging around just not far over water and can't get the error message back so now its back with DJI who recommended I send it to them to assess.
It would be good to have an understanding of the issue to better manage the risks and good to know how DJI responds to those that may not have been lucky enough to be retreived

Welcome to the forum! [emoji106][emoji16]

 

[Drone Master]

Welcome to Mavic Pilots! Enjoy the forum!
There are threads in our Mavic Crash & Flyaway Assistance
Check some of those out!

 

[Thomas B]

Welcome to the forum from the deserts of Arizona! Enjoy.

 

[dirkclod]

Welcome to the forum.
I hope you will find our site helpful and look forward to any input , photo's/video's you might post .

 

[MAvic_South_Oz]

Welcome to the forum Brett.
I don’t see an air data link in your description or text / comments ?
It would be good to post the txt log for the flight (and dat if you have it ???).
The analysis here is first rate.
If yours had a uncontrolled descent issue, it’s possible DJI might replace it.
They’ve been replacing ones lost like yours was close to joining the party.
EDIT - post in the Mavic crash / flyaway section.

Where are you located ?
Nice beach / surf scene going on there.

 

[Dedal]

Welcome. Post some data so it can be seen what was happening.

 

[Legendberry]

Welcome to the forum Brett.
I don’t see an air data link in your description or text / comments ?
It would be good to post the txt log for the flight (and dat if you have it ???).
The analysis here is first rate.
If yours had a uncontrolled descent issue, it’s possible DJI might replace it.
They’ve been replacing ones lost like yours was close to joining the party.
EDIT - post in the Mavic crash / flyaway section.

Where are you located ?
Nice beach / surf scene going on there.

is the airdata info adequate...... This is Avoca Beach on the Central Coast I was hoping to capture some good shots of the large swell but it was doing something I hadn't seen before... So I should start a new post in the crash/flyaway section

 

[Dedal]

is the airdata info adequate...... This is Avoca Beach on the Central Coast I was hoping to capture some good shots of the large swell but it was doing something I hadn't seen before... So I should start a new post in the crash/flyaway section

Actually, the admins could move the post...

 

[slup]

This isn't anything other then the usual "uncommanded descent" for a Mini ... for reasons not yet firmly proven, the Mini don't manage to create enough propulsion/lift. Some thought's have pointed at the props, design wise or how they remain shape during storage/usage ... other to Vortex ring state but none of them fit fully to the symptom.

Each event like this usually shows both roll & pitch instability through out the flight ... so does your's. The Mini shall be able to reach 30 degree pitch in Sport mode acc. to spec but during your flight & the initial Sport "session" you Mini didn't manage that at all, mainly 15 degrees & only once during a short max elevator input it reached just over 25 degrees.

The critical event in your case starts at 951sec with a sudden large up pitch (Green) with only max positive elevator applied (Grey). Short after you command descent with the throttle (Blue), release it but the Mini continue to descend (Red) ... this with a heavy pitch instability. After this you only command positive throttle & elevator & can luckily gain some height & limp back to safety.

DJI have constantly answered "- try calibrate" ... if the drone still isn't lost or crashed. Once completely crashed & even lost not possible to retrieve they have so far replaced the Mini without any questions. This proves that they know more then they say about this design flaw.

Simple put ... the Mini isn't safe to fly, if you do you need to be prepared to lose it.

If you also supply the mobile device DAT log we can look at the motor rpm's & nail this event even harder ... The DAT log we need have FLY011.DAT in the end.
Check here how to retrieve it --> Flight log retrieval and analysis guide read under point 3.

 

[sar104]

This isn't anything other then the usual "uncommanded descent" for a Mini ... for reasons not yet firmly proven, the Mini don't manage to create enough propulsion/lift. Some thought's have pointed at the props, design wise or how they remain shape during storage/usage ... other to Vortex ring state but none of them fit fully to the symptom.

Each event like this usually shows both roll & pitch instability through out the flight ... so does your's. The Mini shall be able to reach 30 degree pitch in Sport mode acc. to spec but during your flight & the initial Sport "session" you Mini didn't manage that at all, mainly 15 degrees & only once during a short max elevator input it reached just over 25 degrees.

The critical event in your case starts at 951sec with a sudden large up pitch (Green) with only max positive elevator applied (Grey). Short after you command descent with the throttle (Blue), release it but the Mini continue to descend (Red) ... this with a heavy pitch instability. After this you only command positive throttle & elevator & can luckily gain some height & limp back to safety.

DJI have constantly answered "- try calibrate" ... if the drone still isn't lost or crashed. Once completely crashed & even lost not possible to retrieve they have so far replaced the Mini without any questions. This proves that they know more then they say about this design flaw.

Simple put ... the Mini isn't safe to fly, if you do you need to be prepared to lose it.

If you also supply the mobile device DAT log we can look at the motor rpm's & nail this event even harder ... The DAT log we need have FLY011.DAT in the end.
Check here how to retrieve it --> Flight log retrieval and analysis guide read under point 3.

View attachment 95896

Agreed - same characteristics. Looking at just the vertical:



Comparing to the horizontal movement, it's clear that towards the end of the flight the aircraft cannot move forwards without starting to descend - the same old problem:

 

[JAW]

Can’t help but wonder how long DJ I will let this go on?

 

[old man mavic]

welcome to the forum

 

[Legendberry]

Thanks so much for your work in interpreting the data. I think DJI Fly may have removed the dat files as I have synced my data and sent the mini back to DJI for assessment. They were quick to recommend I return it giving me the impression that its a known issue. Given its probably setting new global sales records I can understand DJI would rather quietly replace rather than publicly release info that could spook the market.
I tried for 2 weeks after to get the error message again (not over water) often flying full power in sport mode but nothing, just dont have the balls to fly over water until I know DJI will replace should it fail and be unrecoverable.

 

[slup]

Thanks so much for your work in interpreting the data. I think DJI Fly may have removed the dat files as I have synced my data and sent the mini back to DJI for assessment. They were quick to recommend I return it giving me the impression that its a known issue. Given its probably setting new global sales records I can understand DJI would rather quietly replace rather than publicly release info that could spook the market.
I tried for 2 weeks after to get the error message again (not over water) often flying full power in sport mode but nothing, just dont have the balls to fly over water until I know DJI will replace should it fail and be unrecoverable.

OK ... yeah, unfortunately quite common that the DAT is missing for the Mini. This means that we can't dig deeper. Would be interesting to hear what DJI have to say ... report back here if you have the time.

 

[Legendberry]

I will certainly provide an update with DJI's response but thinking it will be light on all that embarrassing detail... thanks again