I watched my drone fall approx 5 feet right in front if me the battery was malfunctioned and and drained way before the aloted time given. I was actually bring it down because the battery was low and around 5 ft the motors just stopped and the thing fell. It cracked the frame but other than that it was in pretty good shape. I think it was because the motors had already stopped spinning so maybe that helped it? I don't know but i swear my heart stopped watching that drone fall.. I couldn't imagine 400 feet.