Head free (Care free) mode uses the compass and your last known position to transform the commanded stick input from your transmitter from the persepective of the copter into the persepective of you the pilot. For most beginner pilots the toughest part of flying is projecting yourself onto the copters orientation so that you can determine how you need to move the control stick. You have to imagine in your minds eye, you are sitting on the copter and facing the same direction. Head free mode removes this burden! The copter control software, knowing where you are, adjusts the stick input so that roll left is always left on the copter from your perspective and roll right is always right, and the same with the pitch. You take away the notion of a "front" on the copter, there is no front anymore!