In this paper, dynamic interpolation is applied to an L1011-100 vertical guidance problem. A flight management system's (FMS) optimized vertical flight plan is used to obtain way points which serve as inputs to the dynamic interpolation algorithm. The algorithm produces reference commands which are issued to a model obtained from a certified FAA L1011-100 and autopilot. The resulting dynamic behavior is compared to the results obtained from reference commands produced by an L1011-like commercial aircraft FMS. Quadratic and cubic spline solutions to the dynamic interpolation problem are presented. Performance degradation with respect to weight uncertainty is examined for both the FMS and the Dynamic Interpolation commands.