I went back to same practice spot as the day before. After reading in several places re-calibration isn't necessary if you are close to where the previous flight was, I skipped the step. I had a nice vertical takeoff to about ten feet. Then, on its own, the Phantom tilted to the right and accelerated to 20mph+, flew about 100' and crashed into a tree, bounced off, flipped over, and dropped from about ten feet into several inches of pine needles. I heard the motors whining and immediately cut power. BTW, these Phantoms are tough. Cleaned all of the debris from the Phantom, replaced two props, CALIBRATED, and she flew fine for two batteries worth. Whew!