On a new Mavic Pro, with current firmware, I have had two incidents where flight became erratic, and unresponsive to control movemenmts.

The latest was this afternoon, where I was flying by remote only. I initiated a "RTH" and the bird starting decending towards a open area for landing.
Unfortunatley, it suddently veered  away, descended rapidly and finally came down in a tree - no apparent damage.

Since there was no phone in the loop, there is nothing to look at, except whatever is stored in the video part of the phone, or within the bird.

Something like this has happened twice. How do I diagnose and wheat to do?

You can contact the DJI Support, provide the data of these two flights for analysis. Besides, I would recommend you connect the RC to the APP in your future flights, there's a lot of information on the APP and it will be more convenient for you to control the drone.

Since there was no phone in the loop, there is nothing to look at, except whatever is stored in the video part of the phone, or within the bird.

There's a DAT file (flight log) stored on the Mavic itself that will provide a lot of information about what happened. The instructions for retrieving it are here, and the correct file should have a timestamp that corresponds to when the flight occurred and will be tens or hundreds of megabytes in size.

Something like this has happened twice. How do I diagnose and wheat to do?

If you upload the DAT file to DropBox and provide a link to it in this thread I'll take a look and let you know what I'm able to figure out.

DJI Diana Posted at 2017-10-16 00:45
You can contact the DJI Support, provide the data of these two flights for analysis. Besides, I would recommend you connect the RC to the APP in your future flights, there's a lot of information on the APP and it will be more convenient for you to control the drone.

This was a one-shot situation, in terms of leaving the phone off.

DroneFlying Posted at 2017-10-16 02:23
Since there was no phone in the loop, there is nothing to look at, except whatever is stored in the video part of the phone, or within the bird.

There's a DAT file (flight log) stored on the Mavic itself that will provide a lot of information about what happened. The instructions for retrieving it are here, and the correct file should have a timestamp that corresponds to when the flight occurred and will be tens or hundreds of megabytes in size.

https://www.dropbox.com/s/350qtbz5cbq4xkj/DJ.zip?dl=0

This is the only data file that seemed to have anything in it. \

Any insights GREATLY appreciated.

I need to get this working reliably, since I am often out in the field, flying over inhospitable terrain to reach archaelogical sites.

djiuser_WmDiHr2 Posted at 2017-10-16 08:32
https://www.dropbox.com/s/350qtbz5cbq4xkj/DJ.zip?dl=0

This is the only data file that seemed to have anything in it. \

I looked at the DAT file and it is a valid one, but it doesn't quite seem to match the description you provided, so is it possible that this file is from a different flight?

It actually shows three separate flights, all in approximately the same location. The first one appears to have ended as a result of some sort of downward sensor blockage (debris in the sensor or landing gear extensions or a tracking device attached?) , and in the other two you triggered RTH and it appears to have landed normally. I didn't see any indication of a crash in any of them and there doesn't appear to be a tree near where the Mavic flew, so I'm not sure what to tell you based on this particular DAT file.

DroneFlying Posted at 2017-10-16 10:10
I looked at the DAT file and it is a valid one, but it doesn't quite seem to match the description you provided, so is it possible that this file is from a different flight?

It actually shows three separate flights, all in approximately the same location. The first one appears to have ended as a result of some sort of downward sensor blockage (debris in the sensor or landing gear extensions or a tracking device attached?) , and in the other two you triggered RTH and it appears to have landed normally. I didn't see any indication of a crash in any of them and there doesn't appear to be a tree near where the Mavic flew, so I'm not sure what to tell you based on this particular DAT file.

Thank you for looking at these log files.

So, I got up this morning, decided that for $1,000 I should not have to start out troubleshooting, went back to Fry's Electronics, and asked for a replacement unit. After considerable discussion, they did swap it out.

So, with another bird in hand, I charged everything up, updated the firmware, installed some prop protectors (after yesterdays experience) and went out for a test spin. Things did not go well.

After a careful lift-off, I tooled around an area trying to gauge the effect of the prop guards. Suddently the mavic started climbing without control input. At 325' I semi-paniced, hjit the stop button to regain control, and started to bring it down. The controls acted strangely, and I had trouble landing. RTH did not work too well either.

I am becoming despondent.

This is my THJRD unit. What am, I doing wrong?

DroneFlying Posted at 2017-10-16 10:10
I looked at the DAT file and it is a valid one, but it doesn't quite seem to match the description you provided, so is it possible that this file is from a different flight?

It actually shows three separate flights, all in approximately the same location. The first one appears to have ended as a result of some sort of downward sensor blockage (debris in the sensor or landing gear extensions or a tracking device attached?) , and in the other two you triggered RTH and it appears to have landed normally. I didn't see any indication of a crash in any of them and there doesn't appear to be a tree near where the Mavic flew, so I'm not sure what to tell you based on this particular DAT file.

can you look at:

https://www.dropbox.com/s/15qn3eg7op0fu5e/dji.zip?dl=0

tnx,

djiuser_WmDiHr2 Posted at 2017-10-16 07:11
This was a one-shot situation, in terms of leaving the phone off.

Data should reserve on the drone. You can provide all the data on the drone to our support team, we will help to start the data analysis if you need. You can contact us on this page: http://www.dji.com/support.

djiuser_WmDiHr2 Posted at 2017-10-16 21:39
can you look at:

https://www.dropbox.com/s/15qn3eg7op0fu5e/dji.zip?dl=0

Based on what I see in that DAT file and what was in a previous one you provided I'm fairly certain that what you're experiencing is caused by something interfering with the Mavic's downward sensors. Do you have landing gear extensions, a tracking device, or something else attached to the Mavic? Or is there something (e.g., debris) blocking the sensors on the bottom of the aircraft?

What's happening is that when the Mavic takes off it keeps ascending until it thinks it has reached a point just above the ground, and while the downward sensor indicates that the ground is still close by it will just continue ascending. That's what happened here until you initiated a landing by pulling back on the throttle (left stick), at which point the process essentially reversed itself: pulling back on the throttle caused it to start landing because it still thought it was close to the ground. I've attached a graph below that shows what's happening: the red plot is your Mavic's (roughly) actual height above ground, the green one is what the downward sensors says the distance to the ground is, and the blue your throttle input. The purple shaded area is when you were taking off, and the cyan shaded portion is when the aircraft is landing.

If you have landing gear extensions installed then make sure they're installed correctly and if they are then discard them and consider a different brand / design. Or if you have some kind of tracking device attachment then consider putting it in a different location. But whatever the case, I'm pretty certain that something is interfering with the Mavic's sensors, and the fact that you've encountered this problem with more than one aircraft strongly suggests that it isn't a product defect.

DroneFlying Posted at 2017-10-17 04:10
Based on what I see in that DAT file and what was in a previous one you provided I'm fairly certain that what you're experiencing is caused by something interfering with the Mavic's downward sensors. Do you have landing gear extensions, a tracking device, or something else attached to the Mavic? Or is there something (e.g., debris) blocking the sensors on the bottom of the aircraft?

What's happening is that when the Mavic takes off it keeps ascending until it thinks it has reached a point just above the ground, and while the downward sensor indicates that the ground is still close by it will just continue ascending. That's what happened here until you initiated a landing by pulling back on the throttle (left stick), at which point the process essentially reversed itself: pulling back on the throttle caused it to start landing because it still thought it was close to the ground. I've attached a graph below that shows what's happening: the red plot is your Mavic's (roughly) actual height above ground, the green one is what the downward sensors says the distance to the ground is, and the blue your throttle input. The purple shaded area is when you were taking off, and the cyan shaded portion is when the aircraft is landing.

Good analysis !

Griffith Posted at 2017-10-17 07:00
Good analysis !

Thank you. It's good to see you around again.

DroneFlying Posted at 2017-10-17 11:04
Thank you. It's good to see you around again.

Busy at work and haven't had much time to check in :-(

DroneFlying Posted at 2017-10-17 04:10
Based on what I see in that DAT file and what was in a previous one you provided I'm fairly certain that what you're experiencing is caused by something interfering with the Mavic's downward sensors. Do you have landing gear extensions, a tracking device, or something else attached to the Mavic? Or is there something (e.g., debris) blocking the sensors on the bottom of the aircraft?

What's happening is that when the Mavic takes off it keeps ascending until it thinks it has reached a point just above the ground, and while the downward sensor indicates that the ground is still close by it will just continue ascending. That's what happened here until you initiated a landing by pulling back on the throttle (left stick), at which point the process essentially reversed itself: pulling back on the throttle caused it to start landing because it still thought it was close to the ground. I've attached a graph below that shows what's happening: the red plot is your Mavic's (roughly) actual height above ground, the green one is what the downward sensors says the distance to the ground is, and the blue your throttle input. The purple shaded area is when you were taking off, and the cyan shaded portion is when the aircraft is landing.

That was, indeed, the problem. Once I removed the crappy, third-party landing gear extensions, everything seemed to work better, and most problems evaporated,

thank you.

rcolman Posted at 2017-10-17 14:57
That was, indeed, the problem. Once I removed the crappy, third-party landing gear extensions, everything seemed to work better, and most problems evaporated,

thank you.

No problem; I'm glad I was able to help.