A new digital computer program has been developed for crashworthy analysis of seating systems in light aircraft. The program utilizes a three-dimensional mathematical model of a seat, occupant, and restraint system to predict the effectiveness of the seat and restraint system in protecting the occupant from the injurious environment of a survivable crash. Input data include detailed descriptions of the seat and restraint system designs. The three-dimensional response of the occupant is predicted for any given set of aircraft impact conditions, impacts of occupant extremities against cabin surfaces are recorded, and the injury potential for a given case is measured in terms of various criteria. The paper includes descriptions of the mathematical development of the model and the organization of the computer program.