The ultralight was on a demonstration flight. Reportedly, the pilot made a pass down the runway, then had turned downwind at 400 to 500 feet, when witnesses heard a loud bang or crack and saw the wings of the vehicle fold. The ultralight then entered a spiral and crashed in a canal. An examination revealed that the wing had folded downward. Compression buckling had occurred at the wing center section. Also, the Mylar skin was found separated from the top and bottom of the wing center section at the bonded attach areas. According to the manufacturer, loss of the Mylar skin on the top of the wing would result in an aft shift in the center of pressure and cause the vehicle to pitch forward. Witnesses thought that the wings had folded upward, but the investigation verified that they failed in a negative mode. After this occurrence, the Mylar material on the Mitchell A-10 vehicles was replaced with Ceconite covering and was riveted in place with aluminum battens. Although the prototype had balance weights, they had been removed from production models to eliminate weight.