Evaluation of the F/FB/EF-111 Ground Collision Avoidance System (GCAS).

Abstract : In support of the F/FB/EF-111 Digital Flight Control System Program Office, subjective and performance data were collected in order to provide the Government and contractor engineers with information needed in the design of a Ground Collision Avoidance System (GCAS) for all P/PB/SF-111 aircraft. The GCAS, one of the new safety of flight systems is being included as part of the Digital Flight Control Computer. The GCAS will serve to alert the crew of an impending ground impact. This decision will be based on sensor data collected mainly from the Combined Altitude Radar Altimeter (CARA). The GCAS, due to the down looking nature of the CARA will not be as effective as the forward looking Terrain Following Radar (TFR) and will only serve to complement this system. Its efficacy will be emphasized in non-TFR modes of flight. The evaluation was comprised of three phases. All were conducted using the simulation and computation capabilities of the ASD/ENECH Crew Station Design Facility. The Phase I evaluation focused primarily on two main efforts related to the prediction power of individual equations within the GCAS algorithm.