The objective of this investigation is a preliminary design for an aerodynamic entry vehicle autopilot. The design was tested to its upper altitude limit which provides information for blending during control system transition from reaction jet to aerodynamic control. The longitudinal axis design is conventional for the short period mode with the difficulty that phugoid control with attitude feedback is not possible during entry. The lateral.directional axis design problem is dominated by poor co-ordination with an additional problem caused by large angle of attack variations. In all cases these problems are characterized by unconventional behaviour of the transfer function zeros. It is concluded that navigational aids are necessary for phugoid control and that aileron to rudder crossfeed reduces the adverse angle of attack effects and improves co-ordination.