What the heck happened?! Scary evening!

[Kaitlyn]

So I went out this evening to fly and everything seemed just fine. Launched fine, flew out for a while and all was well, then my video was frozen and I couldn't see what was happening - then the app crashed/nexus 7 (2013) automatically restarted. Thankfully I was able to bring it back by eye, and it responded to the remote perfectly fine. Flew it again after that without problem.

Then I switched the battery and it wanted me to recalibrate (do the dance), which I did. I then noticed it seemed to not want to lock on GPS (hovering around 15-16 with low bars), and I tried moving it a few times to avoid potential interference. Eventually it did get it and I took off as I normally do - but it just flew away! It was right over water and my heart was pounding, but thankfully I was able to bring it back in and landed it. During the return where I was "overpowering the wonkiness" it did seem to regain "control" and I was able to bring it in smoothly (but I feared it'd go crazy again at any second). What the hell happened!?

Not a good night for my faith in DJI .

 

[Meta4]

Then I switched the battery and it wanted me to recalibrate (do the dance), which I did.
.... Eventually it did get it and I took off as I normally do - but it just flew away! It was right over water.
During the return where I was "overpowering the wonkiness" it did seem to regain "control" and I was able to bring it in smoothly (but I feared it'd go crazy again at any second). What the hell happened!?.

The app crashing is down to the tablet and not anything about the Phantom.
Where you say ..

Then I switched the battery and it wanted me to recalibrate (do the dance), which I did.

This sounds like the root of the problem.
You can safely go for months without having to recalibrate the compass.
When you say it wanted you to recalibrate ... this is wrong.
The compass error was telling you that the compass had detected a magnetic field different from the earth's normal magnetic field.
It would have been because you were close to something steel or an electric cable ... most commonly reinforced concrete.
The correct action would have been to move away from the magnetic influence and not recalibrate the compass.
By recalibrating in the distorted field, you gave the Phantom a bad calibration and when the Phantom got out of that field and into the earth's normal field, the compass was in trouble because it was still compensating for the extra magnetism.
Here's an example of someone doing this:

Any time you want to investigate a flight, you can make use of the "black box recorder" in the app to find out what went wrong.
Go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone can usually make sense of it for you.

 

[Kaitlyn]

The app crashing is down to the tablet and not anything about the Phantom.
Where you say ..

This sounds like the root of the problem.
You can safely go for months without having to recalibrate the compass.
When you say it wanted you to recalibrate ... this is wrong.
The compass error was telling you that the compass had detected a magnetic field different from the earth's normal magnetic field.
It would have been because you were close to something steel or an electric cable ... most commonly reinforced concrete.
The correct action would have been to move away from the magnetic influence and not recalibrate the compass.
By recalibrating in the distorted field, you gave the Phantom a bad calibration and when the Phantom got out of that field and into the earth's normal field, the compass was in trouble because it was still compensating for the extra magnetism.
Here's an example of someone doing this:

Any time you want to investigate a flight, you can make use of the "black box recorder" in the app to find out what went wrong.
Go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides and someone can usually make sense of it for you.

Hmm - it SOUNDS like that's my exact problem (eek!). Guess I should make sure to recalibrate again regardless in an open field sort of setting?

I wonder why I WAS able to get it back in safely - maybe because once I got in close enough it was back to working within the wonky conditions, hence why I had total control over it?

What is now scary, however, is that I can see all the log files - but the files from today I see are my first safe flight and the very last one where I never actually took off - there is no log of this wonky flight!

 

[Meta4]

Hmm - it SOUNDS like that's my exact problem (eek!). Guess I should make sure to recalibrate again regardless in an open field sort of setting?
I wonder why I WAS able to get it back in safely - maybe because once I got in close enough it was back to working within the wonky conditions, hence why I had total control over it?

Yes ... get a good compass calibration out away from any cars, structural steel buried pipes and especially reinforced concrete.
Once you have a good compass calibration you should be good to go.

 

[henick]

RE: fresh calibration in open field

And I wouldn't personally fly it all until that is done. IMO. A bad calibration has been the end of many a phantom and you were right to feel nervous enough about it to ground it.

You may have just learned an important lesson on the cheap

 

[Kaitlyn]

Okay so when I connect my android device, the flight log definitely doesn't seem there. When I have android connected to RC to phantom, I can see it in my flight logs. Are they somehow different? I can watch the path and everything. I've synced it to DJI cloud - but is there a way I can download/share this? All it will let me do is a share, but I can see through their interface it also shows joystick input, etc. etc.

 

[Kaitlyn]

Alrighty - I improvised a solution, screen recorded the DJI app... here it is - any ideas what was going on indeed? You can see especially when it starts to go weird, I have full throttle in one direction and it is just not going where it should be at that point...

 

[Meta4]

Okay so when I connect my android device, the flight log definitely doesn't seem there. When I have android connected to RC to phantom, I can see it in my flight logs. Are they somehow different? I can watch the path and everything. I've synced it to DJI cloud - but is there a way I can download/share this? All it will let me do is a share, but I can see through their interface it also shows joystick input, etc. etc.

On an Android phone or tablet, the flight records are in Internal Storage/DJI/dji.pilot/FlightRecord
They are all txt files and the file name includes the date.