Here's a couple of approaches. I'm using an Android device. If you're an Apple person, you're half on your own!
I connect my Galaxy S5 to my PC. PC sees it as an external device. Search through the Phone until I find the DJI folder, then the pilot folder, then the logs folder. Thre's a gob of flyxxx.txt files in there - but they ain't text files. Copy one or more to your computer.
Then go to one of the following - maybe both will work -
Settle back in your chair - this is long - I'll try to keep to the point.
My choice of device here is a Galaxy S5 phone. If you're using an iOS device this technique will most likely need to be modified.
I connect my phone to my PC with the charging/USB cable. The PC "sees" it as an external device.
Open "phone" to get to folders.
Find the DJI folder
Find the pilot folder
Find the log folder - this should all be very straightforward
Inside the "log folder" you'll find an array of flyxxx.txt files. They're not text files - they're binary. Copy one or more of them to your PC in a temporary location. It might help if you go back to your Pilot app and quickly review your flight records. Then, when you choose a file you'll know the proper date/time to grab one - pain in the butt to grab one where you sat on the ground just testing!
Open browser - navigate to
www.djilogs.com
Upload the pilot log (you can only do one at a time) and convert to the file type of your choice.
CSV files are comma-delimited files that can be seen in Excel. There is an overwhelming amount of data available, particularly in the comprehensive CSV format.
Now that you have your CSV file, go to
www.flightreplay.com and you can actually view your flight. Apparently the actual .txt file is of great value to the engineers at DJI - they can get a really good idea of what went wrong.
There's another step as well, but, if your Phantom is in pieces, this one will not work for you. But I'll pass it on anyway.
Inside your Phantom - now that yours has been eviscerated you might be able to see it! - is an internal SD card. It's epoxied in there somewhere and wasn't designed to be removed. But, when your Phantom works, you can access the data. With everything connected and running (P3, Pilot app and RC), tap the Flight Mode icon, then select Advanced Settings, the select Enter Flight Data Mode.
You will then be prompted to connect a cable between the front USB port on your Phantom (it's underneath that little rubber door below the Phantom logo on the front) and your PC and download the .dat files - flight records.
Once you have your pinkies on those .dat files, you can go the route above (djilogs.com) and covert the same way - see the data, see the flight, etc.
So, without total destruction, there's two ways to gain access to the flight record data - you're down to one but there's still a good chance you can retrieve the data from your device and get it to DJI - MAKE A COPY OF WHAT YOU SEND!
Good luck - hope this helps.