I did 3 flights with my quad this morning and the first flight went flawlessly. On the second one, the quad suddenly yawed about 45 degrees really fast to the left. I thought it was the wind or a fluke, so I brought it down (with a hard landing) then fired it up again. Same thing happened about 2 minutes into the flight, suddenly yawed really fast at about 45 degrees and starting drifting away from me but I recovered and brought it down safely. (my piloting skills are getting better) .
I was flying in stable mode the entire time, I'm on 2.0.33, with gps, and no magnetometer. Why would this have occured? Could it be a faulty motor or ESC? I checked all connection and found everything to be secure.