An active Ground Collision Avoidance System (GCAS) has been developed for the F/A-18 using the Naval Air Warfare Center Aircraft Division's F/A-18 simulation. The simulation has been used for the development of all three components of GCAS: (1) the algorithms used to determine the recovery initiation altitude; (2) the additional flight control laws (FCL's) necessary to perform the recovery maneuver; and (3) the visual and audio cues used to provide recovery status information to the pilot. The use of a simulation has allowed the rapid development of a viable F/A'18 GCAS that incorporates technology from the F/A-18 Integrated Fire and Flight Control (IFFC) simulation and the Advanced Fighter Technology Integration (AFTI) F-16 program. Complete system development and preliminary evaluations were performed using the simulation. This increased overall project safety while decreasing development and potential flight test costs significantly.