Human transient into-the-loop simulation for NGATS

Serious planning is underway for the United States Next Generation Air Transportation System. While design decisions are far from complete, there is consideration of having aircraft-trajectory control in space and time be determined by some combination of pilots, air-traffic personnel, and computers. Insofar as any control input is continuous in time, because of human perception and decision response times and/or computer multitasking or optimization-cycle times, there are likely to be time delays (e.g., human transients getting “into the control loop”) that could threaten control stability. Using the MATLAB Simulink dynamic simulation tool this paper examines some hypothetical situations and offers examples of how delays and signal sampling in aircraft control could cause unacceptable oscillations and instability.