Trajectory design for aircraft taxi automation to benefit trajectory-based operations

Trajectory-based operations constitute a key mechanism considered by the Joint Planning and Development Office (JPDO) of the U.S. for managing traffic in high-density or highly complex airspace in the Next-Generation Air Transportation System (NextGen). With this concept applied to surface operations at major airports, current research has been exploring the use of surface 4-dimensional (4D) trajectories, which require the taxiing aircraft to meet required times of arrival (RTAs) at selected locations along the taxi route. Observing these RTAs as constraints along the taxi route, the flight still has many degrees of freedom in adjusting its state profiles (i.e., position, velocity, etc. as functions of time) to achieve the timing constraints. Previous research has applied the trajectory control freedom to assure passenger comfort by keeping the accelerations and decelerations within prespecified limits. This paper explores untapped flexibility in the trajectory design problem to achieve additional desirable behaviors, beginning with the consideration of fuel burn, emissions, and noise. A flight-deck automation experimental prototype serves as the platform for evaluating the designs. The findings will benefit future designs of flight-deck automation systems, as well as tower automation systems which rely on accurate understanding of the flight deck's operational behaviors to plan efficient and safe operations for the entire surface traffic.