Development of a conceptual aircraft design system based on ACSYNT, an aircraft synthesis program written by the NASA Ames Research Center; is discussed. The system, named ACSYNT/VPI, was written using the PHIGS graphics standard for machine independence and designed based on top·down principles and standards. A functional description of ACSYNT is presented as well as detailed software requirements for ACSYNT/VPI. The software's design is covered in depth including design philosophies and software functional specifications. Program output and design results are presented in conjunction with project recommendations. The appendices include supporting design and development information.</P / Master of Science