Up until 2 days ago, I had never had any GPS errors or really any mishaps or crashes. I did have to send the bird back to DJI last month for a shell replacement due to some stress cracks on one of the arms, but DJI replaced the entire shell under warranty and I have had over 75 successful flights since it has been back with no problems.
Now the one thing that is really weird is the day before this I was flying along just under 400 ft in an entirely different location and I had the same thing happen. The bird started to tumble and I got the "motor obstructed" message and I watched in horror as the video showed the bird tumbling down to earth. However, that time the bird recovered itself and started to hover and I was able to fly back to the home point after letting it hover for a little bit to recover my composure and make sure everything seemed to be working OK again.. That time I figured it was some kind of bird strike from behind (like a hawk thinking it was prey) even though I did not see any birds and I could see from the live video nothing was in front of me and I was traveling forward. Of course when I got the bird back to the home point I checked everything. There were no signs of anything hitting the bird, no smears like feathers or feet hitting the blades, the motors all seemed like they were spinning freely and none of them were hot to the touch. Even so I recharged the batteries, waited for the bird to cool down so I could do a cold IMU calibration and then flew a few test flights over a large grassy area with no problems and no errors popping up on the screen during the flights so I thought I was in the clear.
Then came yesterday. I had a full 16 minute flight before the dreaded fall with no problems at all. I did compass calibration before the flight and had full GPS signals and the "safe to fly" message before take off on each flight. There was very little wind and everything seemed fine on both flights until it all went so wrong. On the first flight I was over the water enjoying the sights and landed at the home point when the battery got down to 30% with no problems and no error messages at all during the flight. I was actually starting to fully trust the bird again since I had now had several successful flights since the tumble the day before and there were no signs of any trouble from any of the flight logs. As a matter of fact just before the tumble into the ocean I was thinking to myself thank God the day before was just a fluke because this is so much fun and I still have the whole day ahead of me for flying (I actually bring an external power source with me so I can recharge the batteries while we grab some lunch). Well, I think God answered back not so fast there because right after that came the fall from the sky and I could only watch the screen in horror as the bird kept tumbling down into the water (I could see from the video that it still had power because when one of the arms came into view as it was tumbling the lights under the motors were still on and working).
One way or another I will get another Phantom. This hobby is just too much fun to abandon it over one horrific day. I will contact DJI on Monday and see if they can figure out what happened and see if they can provide any assistance in getting a replacement bird. Actually, all I really need is just a new bird since I have a controller already, but I don't know if DJI ships just a bird by itself. Anyway, thanks for listening to my long sad story. Hopefully someone here or at DJI will be able to determine what went wrong, but I have a feeling we may never know for sure what happened.