This paper discusses the Micco spin flight test program for the FAA Part 23 certification of the MAC-145A and the MAC-145B light single engine aircraft. The 145A was awarded FAA certification in January 2000 in the Utility Category (spins prohibited in operation use). Approximately 120 one turn spins were completed in the flight test program with no anomalies or safety incidents. The 145B, and increased power derivative of the 145A, was intended to be immediately certified in the Acrobatic Category which permits spins and acrobatic maneuvers. However, spin flight tests of approximately 210 spins revealed that the 145B, in its current configuration, could not meet the Acrobatic Category recovery criteria for multiple turn spins. It is now intended to certify the 145B in the Utility Category (spins prohibited) until further modifications and flight tests can be completed.