When I do a Calibration. My first rotation is green then second rotation is a momentary split second yellow then instant slow green double. When I fist turned my bird on my app displayed "MC Calibration Needed" I performed the calibration and got the above results. Bird does not drift and maintains hover within 4-5 foot radius. Put your bird in a hover in front of you at about 6' and grab on of the skids and gently pull it to one side or the other. You should feel and here the rotors trying to compensate for the drag. if this occurs you are in GPS Mode.