Mavic 2 Pro out of control, crashed into lake... help?

[BudWalker]

even if it was a hit - it does not properly explain how and why for exactly one sec with no throttle input it went up drawing crazy current - from 5m 22.8s till 5m 23.8s, then drops down ignoring given throttle up. it rotated and spinned prior to that climb, but stopped spinning during the climb. odd.
if you know structure of the xls file - does it have any metric for level of vibrations?

The only thing I can offer is that when my M2 experienced a mid air impact (bird strike) there was uncommanded lateral movement.

My Bird Strike

It also had this in the eventLog stream
147.537 : 10017 [L-FDI][CTRL]: fault on , impact_in_air
147.557 : 10018 [L-RC]craft ctrl failed!!!
147.676 : 10024 [L-FDI][CTRL]: fault off, impact_in_air

and nothing like this in this incident.

 

[Gryphon962]

Typically, if all or part of a prop is missing the AC will start rotating because the missing prop is no longer providing angular momentum. A propulsion issue in the rightFront and leftBack will cause the CCW rotation seen here. (BTW, it was the right Front not the leftFront). The P3 would just rotate and corkscrew into the ground but the Mavics also start tumbling.

I'm going to speculate that it was just a small piece that went missing. Although there was CCW rotation it was much slower than is typically seen. Also, the rightFront commanded only went to 92% where usually it'll go to 100%. And, the M2 was able to recover in the sense that it didn't spin and tumble it's way down.

Let me re-iterate that I'm not entirely satisfied with this analysis. It's tough with just the tablet .DAT.

If a part of a blade went missing, that's mass being flung off at speed; that should result in a lateral g impulse. The 4 g spike we see was for only 0.2 sec, but I havent done the math to determine whether that is consistent with a few grams of blade departing at a certain rpm.

 

[RayOZ]

As I said before, if there's an impact, there would be a warning about it, which this one doesn't. If one of the props had a slight tear, which broke off mid-flight, it would have lost lift and fall, not go up. A while ago, there was someone who had half a prop broke off, but this M2 returned home safely.
@codaroommedia Were you recording video at the moment of the incident? Maybe there was something that can be gleaned from it.

 

[codaroommedia]

As I said before, if there's an impact, there would be a warning about it, which this one doesn't. If one of the props had a slight tear, which broke off mid-flight, it would have lost lift and fall, not go up. A while ago, there was someone who had half a prop broke off, but this M2 returned home safely.
@codaroommedia Were you recording video at the moment of the incident? Maybe there was something that can be gleaned from it.

I was, or so I thought... but there was nothing from that flight in the cache. I’m assuming cache was full?

 

[RayOZ]

I guess DJI must be equally stumped by what happened to it. There was nothing to point to pilot error and decided to just give you a replacement.

 

[Ken-Mav-Mtl]

I recently posted about an issue regarding a missing link-pin from a brand new non-DJI low noise Mav Pro propeller. Ordered new low-noise props from Amazon, thought I was getting genuine DJI product, but they turned out to be a cheap knock-off.
From the images I posted, it shows that a link pin fell out of it's socket, and this happened after my first flight with my Mav Pro. I was lucky to spot this before my next flight.
If this propeller link-pin falls out during flight, I imagine that it would exhibit some erratic behaviour before falling out of the sky, and there would be no sign of contact with any flying object such as a bird.

 

[RobH2]

Could it have been a controller stick malfunction? Lately, every time I turn on my Mavic Pro controller it alerts me to "stick error" and I have to calibrate the sticks. The first time it happened it took me an hour to calibrate them and I had to push really hard, almost thinking I was going to break them off, to get the blue dots into the corners. After that, I can get the blue dots into the corners but I keep getting this error.

I'm a bit afraid that one of the sticks is going to just lock at some input (in a turn, in a climb, etc.) and cease to function. I have a job to do over water and I've chickened out 3 times now going to do it fearing a controller malfunction and loss of the drone into the water. For the past few weeks I've been flying in a field, daring the controller to hiccup or misbehave. It hasn't. So maybe my fears are unfounded.

I wonder if your stick's input got locked and never came back to zero upon releasing them?

 

[sar104]

Could it have been a controller stick malfunction? Lately, every time I turn on my Mavic Pro controller it alerts me to "stick error" and I have to calibrate the sticks. The first time it happened it took me an hour to calibrate them and I had to push really hard, almost thinking I was going to break them off, to get the blue dots into the corners. After that, I can get the blue dots into the corners but I keep getting this error.

I'm a bit afraid that one of the sticks is going to just lock at some input (in a turn, in a climb, etc.) and cease to function. I have a job to do over water and I've chickened out 3 times now going to do it fearing a controller malfunction and loss of the drone into the water. For the past few weeks I've been flying in a field, daring the controller to hiccup or misbehave. It hasn't. So maybe my fears are unfounded.

I wonder if your stick's input got locked and never came back to zero upon releasing them?

No - because the spurious control input would have been recorded in the log - that documents the control input that the aircraft actually receives, not the physical position of the stick.

 

[nilomiclat]

Thank you! DJI confirmed this morning that it was indeed a warranty issue, and they’re replacing the M2P. However, they wouldn’t really say what happened or what caused the unusual behavior. I’m still very interested to see what happened, definitively, because like a few of us have said, something like this happening and hitting people/property/god forbid my little cousins tubing on the lake, this could cause real damage and/or injury.

Thank you guys, again!

My MP2 crashed last year. It just dropped in midair. I have a DJI Refresh so I got a new one but DJI did not really explained what happened. I’m not as comfortable flying since then.

 

[globetrotterdrone]

My MP2 crashed last year. It just dropped in midair. I have a DJI Refresh so I got a new one but DJI did not really explained what happened. I’m not as comfortable flying since then.

You never asked or did DJI never tell?

 

[Not A Speck Of Cereal]

I guess DJI must be equally stumped by what happened to it. There was nothing to point to pilot error and decided to just give you a replacement.

My speculation: the quick turnaround indicates that they found something they recognized / know is their problem, but don't want to say.

I just hope it's something fixed in a future firmware update (and this is the main reason I always accept new firmware updates), for the bugs fixed but not disclosed.

Chris

 

[John Lord]

Hi,

A similar thing happened to a friends Mavic 2 Pro. It was flying over a lake at 33ft when it descended and crashed into the lake and was lost. The presence of alligators in the lake meant it was not conducive to make an attempt to recover it. DJI Care Refresh does not want to know because they stipulate the kit has to be returned to them intact. DJI Customer Support have analysed the data and say the crash was due to the rudder stick being pushed leftward and the roll stick rightwards and therefore it was pilot error. The fact that these are the inputs you apply to fly anti-clockwise around a subject keeping it in the frame seems to cuts no ice with DJI. There was nothing to conflict with the craft at the time. Our feeling is that DJI are covering up a possible error in their software that under a certain set of circumstances can cause a crash. There were some warning messages including switching to backup IMU twice and upward obstacle on more than one occasion even though no obstacles were involved. My friend and I have been in dispute with DJI over this since the beginning of May but they are so arrogant we have just got nowhere.

 

[Not A Speck Of Cereal]

Yeah, but in this case, DJI covered the loss immediately.

 

[Meta4]

DJI Customer Support have analysed the data and say the crash was due to the rudder stick being pushed leftward and the roll stick rightwards and therefore it was pilot error.

If DJI was suggesting that the pilot pushed the joysticks to the CSC position (the words used don't make that clear), that would show in the recorded flight data.
If they were saying that the left stick was pushed left and right stick to the right, that does not explain the incident as it would not cause a fall-from-the-sky incident.

 

[JSM]

Thank you! DJI confirmed this morning that it was indeed a warranty issue, and they’re replacing the M2P. However, they wouldn’t really say what happened or what caused the unusual behavior. I’m still very interested to see what happened, definitively, because like a few of us have said, something like this happening and hitting people/property/god forbid my little cousins tubing on the lake, this could cause real damage and/or injury.

Thank you guys, again!

Glad to hear DJI are going to replace the MP; warm comfort however as you probably will not ever find out what caused this and sounds like an extremely rare occurrence? Maybe some one will come up with some sort of inflatable "device" that can be fitted if you are flying over water !!!!, just enough to keep the craft afloat!

 

[ff22]

Glad to hear DJI are going to replace the MP; warm comfort however as you probably will not ever find out what caused this and sounds like an extremely rare occurrence? Maybe some one will come up with some sort of inflatable "device" that can be fitted if you are flying over water !!!!, just enough to keep the craft afloat!

There are foam pontoons and other floatation devices for it. There's also a device containing a substance that reacts to water. It is designed to allow water to slowly enter the cartridge and then the cartridge pops up to the surface with fishing line and you can reel in the drone. So, yes, they have you covered.

 

[BJR981S]

It’s been pointed out to me that if the M2 Pro is launched more than 50 miles from its previous location it will ask for a compass calibration. It does this by giving a magnetic interference error on main screen. However the compass is fine no magnetic interference but DJIGO4 is going to ask for a calibration.

So the drone or DJIGO4 must know you have moved over 50 miles.

I have M2 Pros and both exhibit this error if I have moved over 50 miles from my last flight.

Issue was driving me nuts as I knew I did not have anything metal near the drone to cause magnetic interference.

Paul C

This would be so it can do a correction on the Magnetic to True North calculation. It was only a small issue previously for an accurate RTH. But now with Waypoints 2.0 it needs this accuracy to hit those waypoints as they are coordinates based on true not magnetic north. I have not personally seen the request on either of my Mavic 2's, but I have not moved flight location more than 15 miles to date with them. I would think that, some seeing it, some not, may have to do with when this FW for the compass recalibration on distance was implemented. I would assume only the latest FW version when waypoints were introduced.

Cheers

 

[BJR981S]

I'm not convinced that this was a compass problem.

View attachment 76208

I would agree with you. Not a compass issue. Flying fixed wing electric models I have seen this issue with an ESC failure. The ESC fails and goes to 100% output on the motor attached.

Cheers

 

[sar104]

This would be so it can do a correction on the Magnetic to True North calculation. It was only a small issue previously for an accurate RTH. But now with Waypoints 2.0 it needs this accuracy to hit those waypoints as they are coordinates based on true not magnetic north. I have not personally seen the request on either of my Mavic 2's, but I have not moved flight location more than 15 miles to date with them. I would think that, some seeing it, some not, may have to do with when this FW for the compass recalibration on distance was implemented. I would assume only the latest FW version when waypoints were introduced.

Cheers

It has nothing to do with correcting magnetic to true heading, and rotating the aircraft gives it no information on declination anyway. It converts magnetic to true by adding the declination that it computes from a global magnetic model in the aircraft firmware.

 

[Meta4]

There are foam pontoons and other floatation devices for it. There's also a device containing a substance that reacts to water. It is designed to allow water to slowly enter the cartridge and then the cartridge pops up to the surface with fishing line and you can reel in the drone.

Flotation accessories appeal to timid flyers but they come with a weight and aerodynamic penalty and are of little use in the (rare) event of a splashdown unless you have a way to get out to where they are floating.