After takeoff, the pilot of the ultralight vehicle climbed to an altitude of 700 ft AGL in the pattern and turned downwind. According to the pilot's partner, the ultralight began a Dutch roll type of maneuver, and after several oscillations, the vehicle stalled and entered a spin to the left. Four other witnesses also observed parts of the sequence of events. According to them, the vehicle's wings began rocking on downwind, then it entered a spin. An exam of the wreckage revealed no preimpact part failure or malfunction. The pilot had approximately 40 hours of fixed wing flight training about 9 years previously. According to the chief pilot for Mitchell Aircraft, the pilot had completed a 1 week ground school course and had 5.3 hours of dual instruction in a 2 place version of the ultralight. On his first solo flight, the pilot did not perform satisfactorily, due to a panic reaction and was advised not to fly solo until after additional dual instruction.