Somewhat hesitant to post this as it appears any mention of a P4 flyaway is met with quite a bit of skepticism, especially given that log files are rarely included.   I, unfortunately, happen to be the lucky recipient of a unit that did just "fly away" (maybe I should go buy a lottery ticket now too...lol)

The P4 is the first drone I have ever bought - I was amazed at how easy it was to fly.  First battery charge followed by some tentative beginner flights, no issues.  Second battery charge (the next day, same location), P-GPS mode, safe to fly, manual liftoff.  Hovering just fine when suddenly the engines went to full throttle - the app said something like "engine max RPM threshold exceeded" and it literally LAUNCHED itself straight up.  Would not respond to any control stick inputs, would not respond to go to home, would not respond to kill command, etc. (not that the kill command would have done much but crash it straight down from a couple hundred feet by that point)

Long story short, it went up and up and started drifting away until we lost sight.  Two hours of fruitless searching with no results...

The plus side - DJI did review the telemetry logs and warranty the lost craft, my new unit arrives tomorrow.  I am still a little frustrated simply because it has taken more than a month to get mine warrantied and a replacement shipped, but I am very happy DJI stood behind the product.  Hopefully I am one of the very few that this will ever happen to with the P4.  

Logs are here:

http://www.phantomhelp.com/logviewer/Q907M28SLKTWLSSJ6HHB/

Most obvious problem is that the machine began to think it was going negative altitude and once that happened I believe all was lost...

Sorry for your loss, Jason. If you have any question when you use your new unit, feel free to post here.

It's not just the altitude that got messed up.
There are several messages that say:
Satellite Positioning Off. Fly with caution
&
[IMU]altitude exception   (In Flight)  please slowly get craft back if craft behave abnormally
These are indicative of a real hardware problem.
Your Phantom also was getting GPS data that told it that it was a couple of thousand feet away from where it really was.

Nice to see DJI replaced it without any problems.

I really was unbelievably amazed at how easy it was to fly - so much so that I posted a short FB video that first day bragging about how this machine was a game-changer for the industry, in my opinion.  So, I was very disappointed when the 'fatal error' occurred, but it does appear to have been a fluke.  Given the lack of others reporting anything similar, I doubt it will happen again.  

Can't wait for the new unit to arrive today!  

Nice! So u got a replacement just like that?!!!!? Crazy! Good crazy!

labroides@yahoo Posted at 2016-5-26 02:48
It's not just the altitude that got messed up.
There are several messages that say:
Satellite Positi ...

I wonder if the GPS-related messages were caused by the discrepancy between barometric altitude and GPS altitude?  This is a perfect example of why a mid-flight barometer failure can be catastrophic.  Even in ATTI it's going to try to hold altitude with barometer, so you can't recover from this by going to ATTI..  

One of those rare situations where an in-flight CSC to kill motprs may be the best choice.  I think OP said that he tried that, not sure why it didn't work.  Or perhaps it did but he had lost visual by then.

Maybe this is another firmware issue. He did it but due to temporary signal lost P4 did not received the kill motors command.
The transmitter must send cut motors command repeatedly until Phantom has received it.
Need to check it out...

jstjohnz Posted at 2016-5-29 15:50
I wonder if the GPS-related messages were caused by the discrepancy between barometric altitude an ...

"I wonder if the GPS-related messages were caused by the discrepancy between barometric altitude and GPS altitude?"
No chance of that.
If the Phantom ever looked at GPS altitude dta there would almost always be a discrepancy.
GPS is useless for altitude data, it can easily be +/- 200 feet or more and swing quickly over time.
That's why the Phantom doesn't use GPS altitude at all.
The problem is due to an electronic malfunction in the Phantom.
Atti would have made no difference.

vad7@yahoo.com Posted at 2016-5-29 17:02
Maybe this is another firmware issue. He did it but due to temporary signal lost P4 did not received ...

We don't know if the OP used the correct kill command for his Phantom.
Since DJI introduced a new method for killing the motors (P4 only), that is a possible area of confusion.
But if you have lost control signal to your Phantom, no amount of CSC or left stick/RTH will have any effect.

The good news is,  Dji replaced it under warranty.  That makes it one of the very rare actual flyaways.  So,  in a way,  you are almost unique.  Special,  even.  I did not see,  in your post,  if the app stopped tracking the Phantom?  According to the Kml file,  the last recorded location was just off Frankford road and N. 40th place.  3312.55 feet bearing 204.80 degrees relative to the takeoff point.  Or at least to the point where you had 100% battery.  Appears to be a tennis court next to a very large house.
Enjoy your new Phantom.  Happy flying.

The good news no person or property was injured, apart from the P4. Very dangerous situation. That type of failure needs very careful investigation. Failsafe should also  operate on separate circuitry.

Phantomski Posted at 2016-5-29 00:51
Nice! So u got a replacement just like that?!!!!? Crazy! Good crazy!

Kind of "just like that".  Had to upload the telemetry data for DJI to review the log, wait several weeks for that review, receive notice that it would be covered under warranty, wait to receive warranty code, wait for replacement from China, etc.

DJI absolutely stood behind the product, but it is a bit of a tedious process - a process I hope I will not ever need to repeat again!

labroides@yahoo Posted at 2016-5-29 03:44
We don't know if the OP used the correct kill command for his Phantom.
Since DJI introduced a new  ...

I have never had a phantom before, so I was using the correct kill command as it is the only one I know.  

Having said that, it took me so long to realize what was happening (and I was attempting to regain control, return to home, etc.) that by the time I sent the kill command it was pretty darn far away and may have already been intermittently losing the signal.  I also may not have held the command long enough, didn't realize until now that it take a continuous signal for the kill command to work.

Kneepuck Posted at 2016-5-29 03:48
The good news is,  Dji replaced it under warranty.  That makes it one of the very rare actual flyawa ...

Yep, I am definitely very special!  lol

My app originally showed only the initial green line on the map and I lost visual sight of the P4 right about the time that the app said download link lost.  At some point while I was driving around the P4 apparently connected again and my app received all that additional map data.  I have no idea how accurate that flight path is (given the massive hardware failure) but the DJI app showed the final location about 100 yards farther Southeast than the log viewer does - so I spent about an hour slogging around the lowlands around that creek, but never found a thing.

jasont Posted at 2016-6-1 10:55
Yep, I am definitely very special!  lol

My app originally showed only the initial green line on t ...

Ah well. Some poor baffled person may have a P4 that he has no idea what to do with.  Maybe he will advertise it or something.

@jasont:I'm writing an academic paper on drone mishaps and I'd like to get a couple more details from you.
There doesn't appear to be a way to PM you on this forum.

If you have time, could you drop me an email to ajohnsonlaird@me.com please?

Thanks
Andy

Glad DJI's replaced the drone Very strange as all flyaway are, too bad you couldn't switch to ATTI mode and recover the drone. Happy Flying!