Well my mavic mini flew itself straight into the lake... Really upset and confused on what happened. I've read a few places don't fly too low above the water, especially don't hover b/c the sensors will mess up with light reflection etc. However I wasn't hovering, I was moving, I had pressed both sticks forward (to go up and forward) was fine for a few seconds launching off near a dock, then it did a curve ball into the water. It went sideways and down hard and fast. I pressed UP harder and it just ignored me. I'm very confused b/c I've flown over water several times with zero issues before. It was a remote area so I don't think it was any wifi interference. Maybe some metal interference, do most docks have metal underwater? I didn't see anything suspicious. The wind was less than 3 mph, I waited for it to update till it said it was safe to fly (8 satellites) and for it to updated my return to home location. I didn't calliberate the compass this time but it didn't ask me to. I just got my drone back from dji from a previous repair, had 1 test flight at my apartment and everything seemed good. I just don't understand why the drone didn't listen to my controls at all, it completely did its own thing. I told it to go up and forward and it went sideways to the right and down. Sadly I was unable to retrieve the drone. As far as next steps go I tried to go to the dji repair website, but it said for replacement to contact customer support. Well the customer support links just lead you in circles so finally I gave up looking and just emailed them. If anyone has any idea of what happened or why I would love to hear about it. I'm extremely sad.
Mavic Mini flew itself into the lake :(
- Thread starter djiuser_Chrono06
- Start date
Post the flight logs. Without those it would be complete guesswork.
Welcome to the forum ... even though it's during sad circumstances.
Smells like a magnetic interfered take off spot long way though ... but we will see once the logs become available.
Go to sar104's comprehensive guide here --> Flight log retrieval and analysis guide read how to under point 3
Retrieve both the phones .TXT & .DAT file & attach them here in this thread.
Smells like a magnetic interfered take off spot long way though ... but we will see once the logs become available.
Go to sar104's comprehensive guide here --> Flight log retrieval and analysis guide read how to under point 3
Retrieve both the phones .TXT & .DAT file & attach them here in this thread.
thanks guys, I had suspected magnetic interference but the guys on fb just laughed at me until I posted the video. Maybe the docks or Pole in the water. I am upset the app didn't warn me about that or ask me to calibrate the compass or anything like it normally does with metal around. i really appreciate the help.
drive.google.com
drive.google.com
RPReplay_Final1582094603.mp4
drive.google.com
IMG_4309.mp4
drive.google.com
thanks guys, I had suspected magnetic interference but the guys on fb just laughed at me until I posted the video. Maybe the docks or Pole in the water. I am upset the app didn't warn me about that or ask me to calibrate the compass or anything like it normally does with metal around. i really appreciate the help.
RPReplay_Final1582094603.mp4
IMG_4309.mp4
You don't have an answer at this point - just a guess.
@djiuser_Chrono06,
Welcome to the Forum!
I hate to see somebody's first post with crash or lost.
I lost a bird my self, I have been there it still sucks after 4+ years.
If you want real answers we need your flight log.
Video may confirm any questions from the flight log.
Yes its still a guess, flight log is what is needed first.
Does this link bring up a PDF?
We can learn from this data, and we all do.
What mobile device were you using?
If you haven't synced your mobile device with DJI, don't do it yet.
Rod
Welcome to the Forum!
I hate to see somebody's first post with crash or lost.
I lost a bird my self, I have been there it still sucks after 4+ years.
If you want real answers we need your flight log.
Video may confirm any questions from the flight log.
Yes its still a guess, flight log is what is needed first.
Does this link bring up a PDF?
We can learn from this data, and we all do.
What mobile device were you using?
If you haven't synced your mobile device with DJI, don't do it yet.
Rod
The video clearly shows that the dock was built on a galvanized support structure. I don’t have a clue if that was your cause, but there was a whole lotta steel around and under your take-off point.
I have seen a lot of threads talking and compass and magnetic interference.
Anyone can explain that what happens to the drone if the compass got totally messed up?
example: what if the compass sensor tells the software one second north and one second south.Will the drone just keep turning 180 degree back and forth? This is an extreme example, but actually I would like to know LOL by theory.
Anyone can explain that what happens to the drone if the compass got totally messed up?
example: what if the compass sensor tells the software one second north and one second south.Will the drone just keep turning 180 degree back and forth? This is an extreme example, but actually I would like to know LOL by theory.
That's not quite how it works, and that's not what causes compass errors. In fact the IMU rate gyros are the primary measurement of rotation, with the initial IMU yaw (heading) being initialized by the compass reading when the aircraft is powered up. After that the compass is used just to correct for drift and bias in the rate gyros - a low-gain sanity check of sorts.
The main problem that you see arises when magnetic interference at the power up location cause the compass to read incorrectly and therefore incorrectly initialize the IMU yaw value. The aircraft then takes off with an incorrect understanding of which direction it is facing. The compass reading generally gets fixed when it departs the original interference, but now the compass and IMU significantly disagree. The rate gyros are the primary sensors during flight, and the sensor fusion algorithm is not designed to reconcile sudden large differences, so now pitch and roll do not drive the aircraft in the expected directions - hence the uncontrolled flight until the FC gives up and switches to ATTI.
Note that the Mavic 2 firmware does have the ability to correct for that specific situation - if the compass reading changes rapidly on takeoff but the rate gyros don't detect any rotation, the FC assumes that the IMU yaw was incorrectly initialized and adjusts it immediately to match the new compass reading. The link below shows the test results that established that behavior. Earlier models did not do that, and I have not seen any evidence that the Mini does it either.
Compass error demonstration
Only a suggestion, but is it possible that the 'Stick Mode' setting was somehow changed in the controls of your phone / ipad? There are 3 standard and one custom setups available where the configuration of the controls can be changed whereby left can be made right / up to down etc. I have thought of changing them myself a few time to have a play around but was aware of the potential consequence of getting it wrong!
thanks for the write up.from everything you are saying and my understanding of motion / gyro control, compass error shouldn’t cause any severe problem if the pilot has basic heli or drone control skills.
If the pilot is not familiar with the stick movement, the common mistake is “not letting the stick go”. Yourself does not even realize that you are pushing or pulling the wrong stick until the crash.
Is this what we can see this with the Mavic Air when it takes off and shortly after performs an uncommanded yaw sometimes? Now that I think of it, it's only anecdotal, but I seem to notice this behaviour when I'm lifting off nearby a pathway which has rebar in it.
If the FC switches to ATTI then pilot control is perfectly possible. The problem is when the aircraft is in P-GPS and the FC is still trying to fly it - then the pilot has little chance of keeping it under control.
That particular phenomenon has been around since the Air was released, and hasn't generally seemed to correlate well with compass interference at power up.
The drone tilted to the right by as much as 50 degree ( gimbal tilting limit of 35 degree + horizon tilted by 15 degree as seen in the video ) before hitting the water. This is way beyond the normal capability of the drone ( 30 degree max ) so some sever failure such as the IMU / motor / ESC / props must have occurred. Magnetic interference alone could not have caused that kind of drastic movement. I think you should be able to get another replacement from DJI.
Think of it this way, keep getting new drones as you use it is not such a bad thing.
Think of it this way, keep getting new drones as you use it is not such a bad thing.
Last edited:
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