Lost my Mavic Mini when it suddenly dropped into a river

[mini_fred]

Hello everyone.

I need help to figure out what happened to my drone, and if I can get a replacement from DJI because I have DJI Care Refresh.

It suddenly started descending by itself even though I was not pressing down on the stick. I am a newbie with less than 2 hours of flight experience, but I know I wasn't descending at the time.

Earlier in the flight I noticed it was drifting slowly sideways when it should have hovered in place.

I tried to retrieve it but I could not find it and didn't want to risk injury in the strong currents with hard jagged rocks just beneath the surface.

Do I have a case for a replacement from DJI as it seems to have malfunctioned and not my fault?

Here is a video of the last few seconds of that flight and the flight log:

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Thank you in advance.

 

[xunhui]

You need to recover your drone for a replacement with the DJI Care Refresh.. I am not sure of your swimming skills but I would have no issues with recovering the drone if it were mine. With that being said, I am in no way saying you should try to recover it by swimming the the creek. Maybe a long pole with with some type of hook attached. As far as the reason for the crash, I'll let someone with that knowledge step in.

 

[boblui]

At the end of the flight when the drone was descending, the flight controller thought that it was doing the opposite ( zSpeed becomes negative in the chart ). There can be something wrong with the IMU. Will need the .DAT file for further analysis. Follow this thread to get the .DAT file : Mavic Flight Log Retrieval and Analysis Guide

 

[Meta4]

Do I have a case for a replacement from DJI as it seems to have malfunctioned and not my fault?

Here's a summary of your flight data:

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Your Mini seems to have altitude stability until after you made a short downward throttle input at 5:25.3.
You only brought the elft stick down for a half second but the Mini continued descending and lost 10 ft without any corresponding joystick input.
Following that it started to sink again at 5:53.3, even ignoring joystick input that should have made it climb at 5:54.1, stabilising at around 6 minutes.
But around 6:38 it started losing height again with full throttle stopping the descent eventually.
At 7:05.2 it climbed 20 ft with no throttle input and soon after following a short down throttle, it sank 25 ft with no joystick input.
A long burst of up throttle only halted the descent but failed to make the drone climb.

At 8:20.1 you gave it full throttle but the drone just sank, losing 15 feet, briefly stabilised and roughly held altitude until 10:0.7 when you gave it positive throttle input for 15 seconds which failed to lift the Mini.

It's final descent started at 10:20.8 with no joystick input.
It sank 6 ft before you gave it full throttle.
Despite full throttle the Mini continued to sink another 10 feet into the water.

It had firmware version 1.0.5 which was introduced to fix the uncommanded descent problem that had plagued the Mini previously.
Even without being able to recover the drone, I'd be inclined to submit a warranty claim as the flight data clearly shows a malfunction which caused the loss.

 

[BossBob]

Pretty sure that all firmware version 1.0.5 did was to alert the user that propellers might need changing by giving tones on shut down and moving the motor on which the faulty (deformed) propeller is fitted. SAR has done a really good investigation into the causes of the mini uncommanded descent that has come to dominate the crash and flyaway section. Have a look at Mavic Mini uncommanded descent tests

 

[Meta4]

Pretty sure that all firmware version 1.0.5 did was to alert the user ...

Before 1.0.5 it was common to see multiple cases of uncommanded descents reported every day.
Since then, the number has dropped to perhaps one per month.

 

[xunhui]

Those numbers do not look right, nor does the creek look 16' deep. I know that is what is shows but something is just not right with the data.

 

[slup]

... the flight controller thought that it was doing the opposite ( zSpeed becomes negative in the chart ). There can be something wrong with the IMU.

Yeah ... something fishy is going on that can't just be explained with deformed props that can't produce lift.

Looking at a earlier period in the flight reveal the same deviation between the barometric height change & the change in Z-speed (ascend/descend speed).

Here below 293sec into the flight we see a ascent from 0,2m to 6,3m height (red graph) ... the first part of the ascent is commanded with the throttle stick (black graph) that is released at 305sec. The ascent are continuing until 311sec though. The odd here is how the Z-speed (green graph) is registered during this period ... when ascending the Z-speed should show negative values but during this height change (between 293-305sec) the Z-speed is mostly positive which should mean a descent. Due to some reason the IMU don't agree with the barometric height change of 6,1m.

But with this said ... this was most probably not a pilot error & should be addressed by DJI.

Pretty sure that all firmware version 1.0.5 did was to alert the user that propellers might need changing by giving tones on shut down and moving the motor on which the faulty (deformed) propeller is fitted ...

That's correct, that firmware didn't do anything more than alert the pilot about to fast rotating motors before the disaster was a fact ... this seems have helped in the sense that pilots change the props & by that the "uncommanded descent" cases have dropped considerably.

 

[Meta4]

Those numbers do not look right, nor does the creek look 16' deep. I know that is what is shows but something is just not right with the data.

What are you seeing in the numbers?
What doesn't look right?
No-one has suggested that the creek was 16 feet deep.
Why are you making that comment?

 

[JAW]

What are you seeing in the numbers?
What doesn't look right?
No-one has suggested that the creek was 16 feet deep.
Why are you making that comment?

I was wondering the same thing, regrading the 16'.
DJI doesn't always require a corpse in order to provide a replacement, particularly if you have Care Refresh and my guess is this qualifies for a replacement.

Recover the little critter if you can safely do it and be mindful of the strong currents that may move it from its initial splashdown.

 

[bmwbob]

I did a similar run up a stream and while setting up to film the mini began descending like it was going to land in the water. Seems once I got too low mini decided it was time to land

 

[hiflyer201]

that stream was really moving but maybe the drone caught on something not too far downstream. I know one thing..don't go into the water looking for it.

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Merle Haggard ..I'll never swim kern river again

 

[mini_fred]

Wow. I am blown away by the insightful and useful replies. I am encouraged and will file a warranty claim later today.

I will also try to get the DAT file and post it here in case it adds any information. UPDATE: The MCDatFlightRecords folder is empty. Could not find the DAT file. : (

A sincere thank you to everyone who took the time to reply.

 

[xunhui]

What are you seeing in the numbers?
What doesn't look right?
No-one has suggested that the creek was 16 feet deep.
Why are you making that comment?

It's final descent started at 10:20.8 with no joystick input.
It sank 6 ft before you gave it full throttle.
Despite full throttle the Mini continued to sink another 10 feet into the water.


Saying as such most would assume that it went in 16 feet under water. I don't think you were trying to say it went 16 feet under water, but the words used were not the best choice, hence the confusion. Using descent and sank at the same time while describing your assessment of the crash can be confusing. It's an interpretation of how words are seen and viewed by others.

It's all good and no issue.

 

[Capt KO]

Hope all the best. Just remember that even a perfectly functioning Mini will descend when low over water. Especially when hovering. The bottom sensors have a hard time with mono colored surfaces. ie; sand, ice, water. I personally stay above 20ft unless I have full visual control to overcome the descent. It’s hard to notice from the camera view on screen, but the altitude numbers will drop so pay attention.

NOTE: this descent issue is entirely different than the “uncommanded descent” defect described.

 

[Flytelandon]

Hello everyone.

I need help to figure out what happened to my drone, and if I can get a replacement from DJI because I have DJI Care Refresh.

It suddenly started descending by itself even though I was not pressing down on the stick. I am a newbie with less than 2 hours of flight experience, but I know I wasn't descending at the time.

Earlier in the flight I noticed it was drifting slowly sideways when it should have hovered in place.

I tried to retrieve it but I could not find it and didn't want to risk injury in the strong currents with hard jagged rocks just beneath the surface.

Do I have a case for a replacement from DJI as it seems to have malfunctioned and not my fault?

Here is a video of the last few seconds of that flight and the flight log:

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For more detailed information, see our cookies page.

Accept third party cookies

DJI Flight Log Viewer | Phantom Help

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Thank you in advance.

Only if u find it

 

[Flytelandon]

You need to recover your drone for a replacement with the DJI Care Refresh.. I am not sure of your swimming skills but I would have no issues with recovering the drone if it were mine. With that being said, I am in no way saying you should try to recover it by swimming the the creek. Maybe a long pole with with some type of hook attached. As far as the reason for the crash, I'll let someone with that knowledge step in.

Id grab a fish too while your in there

 

[Flytelandon]

Hello everyone.

I need help to figure out what happened to my drone, and if I can get a replacement from DJI because I have DJI Care Refresh.

It suddenly started descending by itself even though I was not pressing down on the stick. I am a newbie with less than 2 hours of flight experience, but I know I wasn't descending at the time.

Earlier in the flight I noticed it was drifting slowly sideways when it should have hovered in place.

I tried to retrieve it but I could not find it and didn't want to risk injury in the strong currents with hard jagged rocks just beneath the surface.

Do I have a case for a replacement from DJI as it seems to have malfunctioned and not my fault?

Here is a video of the last few seconds of that flight and the flight log:

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Thank you in advance.

Why cant I view anyones flight logs when posted in here?

 

[Serhiy]

Unfortunately, this is not the first such loss. I've already read about several similar cases. Above the water, the sensors begin to behave not quite correctly, so you should not go below 5-10m above the water surface. High banks and trees could aggravate the problem in your case, they could weaken the GPS satellite signals.

 

[Deleted member 103366]

Why cant I view anyones flight logs when posted in here?

They are only stored on phantompilots for a limited period of time, may be that time has expired.