First fly away!

So I had my first fly away this weekend. Have had my Phantom 3 for about two weeks and I've gotten pretty good at flying it, not an expert but definitely good enough. It happened so fast, but I just stopped myself and said, "Don't panic, think this through." So I wanted to ask how common this sort of event is because it was very scary and had I not been 10 miles outside of town I would have hit a building or a car or a person and that would have been terrible.I'm going to tell the whole story because I don't know what parts may or may not be relevant. I'd really like to understand if I caused this or if fly aways can happen anytime for whatever reasons cause them.So it starts with me buying a brand new battery for my used Phantom 3. It was generic, but it showed up and I charged it. As soon as it was charged I went out for a drive. I stopped at a spot near the river and started to get things set up. For some reason my phone wouldn't connect to the drone. I tried and tried but couldn't do anything. The drone would fly and it was in GPS mode so it was flying just fine, but no camera, no stats nothing. Restart everything. Nothing. Restart my phone. Nothing. I end up looking in the first screen of information and it said there was extreme interference in this area fly with caution. I looked around, I didn't see a damn thing. There was a river on my left, a field with cows on my right. That's it. I gave up and drove on down the road.I get to a field about 5 miles away and start again. I power everything on and my camera is now back, but now it tells me I have to upgrade the firmware on my battery. This is a new concept to me so I figure it's a nice feature, but not required to fly. Everything is ready, but now it says compass error on my screen. I decide to restart everything one more time. I power off the controller and as soon as it is off the drone flies up into the air. I can't remember if I had the engines running or if they spun up on their own. It flies up, forward, and left at the exact same time in this huge probably quarter mile arc. It gets 200 feet away over the field before I get the controller turned back on. It comes on, shows me the compass error again, but no camera, no control. I pause and think, there is literally nothing I can do except try the controller again. I watch it fly more, it's now about 180 degrees through the circle it is flying in, but now instead of being in a soy bean field it is heading over a forest behind me.I power off the controller. I power it back on. The drone is now over the forest and I've lost sight of it. I'm definitely thinking my drone is gone, it's going to keep going up until the batteries die and by then who knows where it might be. But somehow the controller connects. I see the trees on my screen. It's trees as far as the eye can see and it's flying really crazy, looks like it's doing donuts on the screen. I press the forward joystick and it moves forward. I press rotate right to pull it out of the counter clockwise circle it was in and it started flying straight. I now have control of it. It's not in GPS mode so I'm controlling the whole thing fighting the wind. It shows I'm just under 6000' feet away and about 150' in the air. I'm not sure if that is accurate or not, but I spin it around and see the huge clearing in the trees where the field was and I press forward.It makes it way to the field and I descend into it. Landing was pretty hard without GPS but I got it done. I powered everything off and put one of my old batteries back in it. I turned it all back on and it was fine. Compass was good, camera view came on, and I flew for about 10 minutes in this area checking it all out.Does anyone have any theories about this? Was it the new battery? Something weird in this area? Powering off the controller when the drone was powered on? Powering off the controller with the engine running? Or just one of those things a P3 will do every 100 hours of flight? It freaked me the fuck out and while all's well that ends well, I want to make sure to learn from this experience. Thanks in advance for any insights you might have. via /r/drones https://ift.tt/3b9NJmX