Loss of control after 1st takeoff of the day.

[Beamer]

I'm hoping this is pilot error, but maybe it is faulty hardware/software?

I have been intensely surprised and crudely awakened to the realities of drone piloting on more than one occasion now when my Mavic 2 Pro attempted to fly off (twice now), shortly after the first takeoff of the day. Rebooting the drone stopped the issue at the time.

The first time, the drone barely returned, having little control with the joysticks maxed out. If I released the sticks (to zero positions) it continued to attempt to rise and fly forward.

The second time was nearly the same, but with even less control and I ended up doing a slow ditch, barely controlled, crash into the sand.

I never tried to let the drone continue it's flight and then RTH, so I'm not sure if that would have even helped (just an afterthought).

Is it possible that the controller was in a non-zero position (slightly pressed) at boot to cause this?

I doubt it, but maybe compass calibration could cause this?

Should I send it in to have it looked at? It happened maybe 1 in 10 flights, but now I fear it happening every time I boot up at a new location.

If anyone has ideas to consider which might be the culprits, please let me know. Obviously I'd like to avoid this in the future.

 

[JAW]

"Build it and they will come."

"Ask it and they will answer."

 

[DDS]

Hmm just guessing but were you flying next to metal objects? also did you have a full gps lock & what mode are you in

 

[Aerial-Pixel]

Have you calibrated the remote? Video below is for the Mavic Pro but M2P is similar. The above comment about GPS lock is good too, make sure you have a minimum of 8 satellites and your home point has been recorded.

 

[sar104]

You need to post one or more of the log files for that flight if you want anything other than complete speculation. I'd start with the mobile device txt log:

TXT log: DJI Flight Log Viewer | Phantom Help

 

[paulatkin73]

post logs pls - the 'released the sticks (to zero positions) it continued to attempt to rise and fly forward' statement most likely indicates that remote was not calibrated and was providing the input - but it can only be confirmed with data in those logs.

 

[Beamer]

No metal objects, both times in very remote areas.

I thought GPS was good, I always wait for the app to say 'Ready to Go (GPS)'...Its possible that I didn't here though, as I don't recall 100%, but it looks like it may have been an issue on the first flight maybe. Yet the DJI app shows 8 sats w/ only one bar missing. GPS was def. good on the second flight.

1st problem flight log: DJI Flight Log Viewer - PhantomHelp.com

2nd problem flight log:

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

Thx for helping out.

 

[Beamer]

post logs pls - the 'released the sticks (to zero positions) it continued to attempt to rise and fly forward' statement most likely indicates that remote was not calibrated and was providing the input - but it can only be confirmed with data in those logs.

The logs seem to show reverse input with forward travel.

If controller Cal was indeed the concern, then why would rebooting the controller and drone resolve it?

 

[Meta4]

I thought GPS was good, I always wait for the app to say 'Ready to Go (GPS)'...Its possible that I didn't here though, as I don't recall 100%, but it looks like it may have been an issue on the first flight maybe. Yet the DJI app shows 8 sats w/ only one bar missing. GPS was def. good on the second flight.

1st problem flight log: DJI Flight Log Viewer - PhantomHelp.com

2nd problem flight log:

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

On the first flight, you launched without a homepoint recorded and had none until 0:10.8

The logs seem to show reverse input with forward travel.
If controller Cal was indeed the concern, then why would rebooting the controller and drone resolve it?

In both flights you had obstacle avoidance reacting to obstacles and that's probably what is making you think the drone is going backwards when you push forwards.
It's unlikely that there is anything wrong with the controller.

Your flight locations are very bad choices for a brand new flyer.
You should go to a large, open area, well away from trees, buildings etc.
You need to learn how to operate the drone without the complications of dangerous obstacles nearby.
It's almost impossible to get into trouble when there's nothing to hit.
But flying within a few feet of trees is very risky, even with experience.
It's likely to be disastrous for a flyer without besic flight experience.

 

[Beamer]

I hear ya on many of your points and appreciate your input.

First flight, I specifically recall being nowhere near obstacles (above middle of the river) when it was acting silly. I know that I was the initial obstacle on both flights. Funky though, as this is pretty much the case for every flight, but only on these two did it behave in such a sporadic way.

Say this happens again, what should be my course of action?

Thx for the tips.

 

[Beamer]

To be clear, the drone was going forwards, away, and clear of anything within 50 ft, while I had the stick at full travel in reverse trying to get it to return... It returned, very slow, but wasn't at all following my inputs as it usually would.

 

[Meta4]

First flight, I specifically recall being nowhere near obstacles (above middle of the river) when it was acting silly. I know that I was the initial obstacle on both flights. Funky though, as this is pretty much the case for every flight, but only on these two did it behave in such a sporadic way.

Say this happens again, what should be my course of action?

Can you point to where on the first flight, you had the issue?
At 0:43.9 obstacle avoidance posted a message that it was Braking Now.
OA can in some situations respond to a low, bright sun and identify that as an obstacle.

 

[Beamer]

Why would the IMU Altitude increase to -40 ft (flt 1)?

 

[Meta4]

Why would the IMU Altitude increase to -40 ft (flt 1)?

Because you were descending for most of the short flight.
The recorded data shows you holding the left stick down for much of the time.

 

[Beamer]

Can you point to where on the first flight, you had the issue?

Between 21 and 24, you see my release of the joys, and it traveled into/towards the river.

There were obstacles, but not throughout the flight, the entire flight was a struggle to regain control and land.

Typically from that far, it's a smooth return and land, even with obstacles. This flight had nowhere near the normal input-to-output response and was very sporadic.

If obstacles were the issue, why would rebooting and flying multiple batteries afterwards have no issue in the exact same location... Seems like it would repeat itself. Just doesn't make sense to me.

Both occurrences were on initial flights at the location, rebooted, and the drone flew normally at the same location.

 

[Beamer]

Because you were descending for most of the short fligght.
The recorded data shows you holding the left stick down for much of the time.

Indeed I was holding the left stick down, as the aircraft was ascending in front of my eyes, as I initially wrote. I took off from the ground, and descended further and further down? Makes no sense.

Light could have definitely been a factor it seems.

At 23 sec, you can see me apply hard left stick down and hard right stick down, while the aircraft continues traveling away.

Also, from what I can see, the left stick is down nearly the entire time. If the aircraft were responding appropriately, I would have at some point, for some period of time had to have left stick up applied. But watching the log, there are only two very short bursts of left stick up applied, the rest is down. This seems to me a clear attempt to regain control of an out of control drone.

Thx for the input everyone. I'll keep an eye on it and see if I can come up with any more inputs/ideas on the matter.

 

[Meta4]

Indeed I was holding the left stick down, as the aircraft was ascending in front of my eyes, as I initially wrote. I took off from the ground, and descended further and further down? Makes no sense.

Looking at altitude and joystick inputs, I do see some problems.
It's odd that in the first 8.7 seconds, where you made no up/down joystick input, the altitude is showing a descent to -6.9 ft.
This clearly shows something is not right.
At 0:23.8, the altitude is showing -40 ft and despite the left stick being held down for almost the rest of the flight, the drone ascends to -31.5 ft at 0:27.2.
That's something else that's hard to understand.
I'm interested in what the VPS sensors were indicating.
I can't tell if the VPS data is correct as I don't know how high the drone was above whatever was below it.
Can you explain how far above the ground (or whatever was under the drone) it was?
That info would be helpful for that particular period and for the whole flight.

 

[sar104]

The first flight record is the more interesting, with discrepancies in the x, y and z directions. It's a little hard to figure out quite what is happening because the GPS quality was relatively poor, but there is clear disagreement between the IMU and other positional data, possibly including compass data:





It would be interesting to see the raw sensor data from the mobile device DAT file, and that might shed a lot more light on what is happening here.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[Beamer]

Ya, its one of those 'Guess ya had to be there.' kinda things...

Here ya go, as requested (hoping this is the right DAT file):

 

[sar104]

Ya, its one of those 'Guess ya had to be there.' kinda things...

Here ya go, as requested (hoping this is the right DAT file):

This is probably not a compass issue - it's definitely an IMU problem. IMU0 and IMU1 (active) disagree on virtually everything. The rate gyros, in particular, are completely different, resulting in completely different solutions for the aircraft attitude. It's pretty much impossible to tell what is correct.



I would start with an IMU calibration, and then another test flight.

@BudWalker - any thoughts on this?