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DJI MM Ocean Incident
466 17 2020-12-15
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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Dear Fellow DJI Patrons,

I have recently had a software/sensor error that costed me my DJI Mavic Mini. I did have DJI care refresh. So my drone has been missing for about 6 days now in the ocean. The first thing I do is analyze my flight data from the DJI fly app and a third party flight path anylyzer software. I anylyze that the batter voltage was too short, and sensor issues. The drone was flying in 10mph wind which triggered a sensor and I got a total of 52 "flight warnings" which were deemed by me irrelevant and false. I have came to the conclusion it was NOT human error. When I emailed DJI support they said they would investigate, the flight record glitched and made 2 39 second flights and then the 10 minute flight of catastrophe. The flight was 10 minutes where everything malfunctioned. When DJI "investigated" they analyzed a flight that was 39 seconds. I wrote many emails saying they had the wrong flight and they insisted to me they had the right flight because the gps cut out. I have tried emailing them after they told me they would give me a 30% off coupon for a new drone and they haven't written back. Tonight I threatened to file a lawsuit for fraud because of the poor action taken and how they told me they would replace it if they found an error. I am so mad and my case number and other info is below. If anyone had a similar experience or questions please let me know. They told me twice "they finished data analysis".

Case #: CAS-5607953-M8F9X9
2020-12-15
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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DJI Mavic Mini Ocean Case

Dear Fellow DJI Patrons,

I have recently had a software/sensor error that costed me my DJI Mavic Mini. I did have DJI care refresh. So my drone has been missing for about 6 days now in the ocean. The first thing I do is analyze my flight data from the DJI fly app and a third party flight path anylyzer software. I anylyze that the batter voltage was too short, and sensor issues. The drone was flying in 10mph wind which triggered a sensor and I got a total of 52 "flight warnings" which were deemed by me irrelevant and false. I have came to the conclusion it was NOT human error. When I emailed DJI support they said they would investigate, the flight record glitched and made 2 39 second flights and then the 10 minute flight of catastrophe. The flight was 10 minutes where everything malfunctioned. When DJI "investigated" they analyzed a flight that was 39 seconds. I wrote many emails saying they had the wrong flight and they insisted to me they had the right flight because the gps cut out. I have tried emailing them after they told me they would give me a 30% off coupon for a new drone and they haven't written back. Tonight I threatened to file a lawsuit for fraud because of the poor action taken and how they told me they would replace it if they found an error. I am so mad and my case number and other info is below. If anyone had a similar experience or questions please let me know. They told me twice "they finished data analysis".

Case #: CAS-5607953-M8F9X9


2020-12-15
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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Edit: Pre flight it told me to calibrate compass I tried multiple times and said successfull once and then told me to do it again so then I took off.
2020-12-15
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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Edit: Pre flight it told me to calibrate compass I tried multiple times and said successfull once and then told me to do it again so then I took off.
2020-12-15
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GaryDoug
Captain
Flight distance : 387753 ft
United States
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Were you launching from something that may have had ferrous metal inside?
Post the flight data file or a link to it.

2020-12-15
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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That sounds like an interesting incident.
If you would like an independent data analysis to find out what actually happened, post your flight data and we'll find out what it says about the incident.

Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions.
That will give a report you can post a link for the report here.
Or since there are three flight records, it might be easier to just post the .txt files here.

It would also be helpful if you could describe the place you launched from
2020-12-15
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DJI Susan
Administrator

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I am sorry for the loss of the drone and the unpleasant experience, I understand your feeling. I had sent you a private message and ask for more details about the accident, please keep us updated, I will double confirm your case with our analyst. Look forward to hearing back from you.
2020-12-15
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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Labroides Posted at 12-15 23:26
That sounds like an interesting incident.
If you would like an independent data analysis to find out what actually happened, post your flight data and we'll find out what it says about the incident.

Thank you so much! I would. I have linked the zip file from phantomhelp.

The link to the viewer is: https://www.phantomhelp.com/LogViewer/8KLO4ETA3WFE33E1OT2T/

Thank you so much!
2020-12-16
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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GaryDoug Posted at 12-15 19:39
Were you launching from something that may have had ferrous metal inside?
Post the flight data file or a link to it.

Hi,
I was not launching from anything metal. I was launching from regular old stone in a very open area. The link to the flight is posted below.
https://www.phantomhelp.com/LogViewer/8KLO4ETA3WFE33E1OT2T/
2020-12-16
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Labroides
Captain
Flight distance : 9991457 ft
Australia
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I anylyze that the batter voltage was too short, and sensor issues. The drone was flying in 10mph wind which triggered a sensor and I got a total of 52 "flight warnings" which were deemed by me irrelevant and false. I have came to the conclusion it was NOT human error.

Here's the story that the flight data tells about the flight.
It's not pretty.

You had already flown on the battery and launched again with the battery showing 61%.

I wonder which firmware version you had because at 8:15.1 with the drone 97 feet up, you applied full throttle for 3 seconds and the drone failed to climb.
After you released the joystick, the Mini started to slowly descend.
Full throttle at 8:22.6 and 824.7 failed to stop the slow descent.
This altitude instability and uncommancded descent was a problem early on with the Mini but fixed with Firmware version 1.0.5.
While this was happening, the drone was being blown slowly toward the east on a course of approx 100 degrees which gives an idea of the wind direction.

There's a lot more altitude instability and uncommanded descending after this.
At 8:36 the uncommanded descent stopped and the drone responded sluggishly to full throttle, climbing quite slowly.
At 9:57.6 you tried to climb with full throttle but the drone failed to respond and descended.
It only started to climb at 10:05.2 and climbed very slowly despite full throttle.

You initiated RTH at 10:30.3 with the drone 340 ft from home and 105 ft up.
You soon cancelled and went to Sport Mode and flew some loops backwards at full speed.

At 11:18 the battery level was 27% and the drone was 335 feet away.
You started flying backwards in Sport Mode toward home and took the drone up to 146 ft.
With full stick in Sport Mode, the drone was having trouble fighting the wind and only going slowly.
You turned the drone around and at full stick it was only making 2-4 mph backwards, away from home.
The Mini is not properly pitching which is necessary to go fast.
Instead of up to 30° tilt for Sport Mode, the tilt angle is no more than 10°.
This is another problem that was fixed with Firmware 1.0.5.

Battery now at 24% and distance = 463 ft.
Altitude is around 140 ft (wind is usually stronger up high).
The drone is not maintaining altitude properly .

At 12:38.8 you try RTH with the drone 780 feet from home but it just blows backwards at 7-8 mph.
You go to Sport Mode again at 13:05.6, but with full stick the Mini is going backwards at 4-8 mph and your confused joystick input takes a wandering course.

At 13:17 Distance = 1170 ft, Battery = 15%
Here you seem to lose direction and steer the drone the wrong way, taking it southeast away from home at a faster speed.
It's back to RTH at 13:37.8 and the Mini is going abckwards at up to 10 mph, getting further away.
From about 13:50, the drione makes a big uncommanded descent and descends from 100 ft to 36 feet with no joystick input.

At 15 minutes, battery is down to 5% and teh distance = >2000 ft with the Mini going backwards at 5-10 mph.
It starts to autoland at 15:03.5 and the signal is lost and data stops at 15:04.1 with the Mini 38 ft higher than the home point, battery at 4% and distance = 2084 feet away from home.
The drone would have landed in the sea soon after.

The whole flight was a mess with poor speed and altitude stability, (probably due to using early firmware ?).
Having more recent firmware probably would have prevented at least some of the problems.

But as well as poor performance from the Mini, there was also poor piloting with the drone left up high where the wind was strong and allowed to blow away.
It should have been brought down where the wind was less and brought home long before it got away.



2020-12-16
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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Labroides Posted at 12-16 06:53
I anylyze that the batter voltage was too short, and sensor issues. The drone was flying in 10mph wind which triggered a sensor and I got a total of 52 "flight warnings" which were deemed by me irrelevant and false. I have came to the conclusion it was NOT human error.

Here's the story that the flight data tells about the flight.

Thank you so much for analyzing my flight. The loops were me trying to figure out the best direction to fly in. The drone had just been updated. I do agree the flight was a mess. I do personally believe it to be a firmware/sensor error. I did try to do rth however it was trying to land it further from home. So I put in into sport mode to see if I could beat wind resistance then the wind kinda took it and I proceeded to try to regain control.
2020-12-16
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GaryDoug
Captain
Flight distance : 387753 ft
United States
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I know this is hindsight "being 20/20", but why did you not attempt to land it anywhere before it got to the beach? I don't see very many down-stick movements, and none during the last 2/3 of the flight. It may not have worked since the up-stick rarely worked but why not try?
2020-12-16
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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GaryDoug Posted at 12-16 08:07
I know this is hindsight "being 20/20", but why did you not attempt to land it anywhere before it got to the beach? I don't see very many down-stick movements, and none during the last 2/3 of the flight. It may not have worked since the up-stick rarely worked but why not try?

The area is some what popular and I did not want to risk landing it on a roof, person, car, etc. I did not want to be responsible for property damage and wanted it to land first back at my house. The town is so close so people would know I would be the culprit of the property damage. I tried to get it to come home if that makes sense.
2020-12-16
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GaryDoug
Captain
Flight distance : 387753 ft
United States
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OK, I hear you....however I am one of those jerks that feel that a 249 gram drone isn't likely to hurt anything ;-)

Also, it looks like that day had a cold front moving through with 16 mph winds from the northwest. In the future I suggest using a weather site like UAVforecast.com to help you decide to fly or not.

Another thing: The analysis shows it landing on the beach. Now that may be in error or the tide may have been higher, but did you search the beach shore or does the video show it clearly going into the drink?....Edit: Nevermind, Now I see that communication was proably lost at an altitude of 38 feet and who knows how far it went backwards after that.

2020-12-16
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GaryDoug
Captain
Flight distance : 387753 ft
United States
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Another thing that may have had an effect was the temperature. The site I use shows it had a high temp of 37 F. At 100 feet, it would probably be lower and the Mini has a low temp spec of 32 F.
2020-12-16
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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GaryDoug Posted at 12-16 08:25
OK, I hear you....however I am one of those jerks that feel that a 249 gram drone isn't likely to hurt anything ;-)

Also, it looks like that day had a cold front moving through with 16 mph winds from the northwest. In the future I suggest using a weather site like UAVforecast.com to help you decide to fly or not.

I understand completely. I don’t think it would’ve hurt anyone either I didn’t wanna risk it though. Your not a jerk, your very helpful and I thank you a lot. Stay safe with the storm coming.
2020-12-16
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Bsantos24
lvl.2
Flight distance : 329121 ft
United States
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DJI Susan Posted at 12-15 23:38
I am sorry for the loss of the drone and the unpleasant experience, I understand your feeling. I had sent you a private message and ask for more details about the accident, please keep us updated, I will double confirm your case with our analyst. Look forward to hearing back from you.

I private messages you the link to the data is: https://www.phantomhelp.com/LogViewer/0VTUWO1GV6MKVEL7G39Z/
2020-12-16
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DJI Susan
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Bsantos24 Posted at 12-16 17:45
I private messages you the link to the data is: https://www.phantomhelp.com/LogViewer/0VTUWO1GV6MKVEL7G39Z/

I have replied to your PM. Thanks.
2020-12-17
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