Aircraft Trajectory Optimization and Contrails Avoidance in the Presence of Winds

Abstract

There are indications that persistent contrails can lead to adverse climate change, although the complete effect on climate forcing is still uncertain. A flight trajectory optimization algorithm with fuel and contrails models, which develops alternative flight paths, provides policy makers the necessary data to make tradeoffs between persistent contrails mitigation and aircraft fuel consumption. This study develops an algorithm that calculates wind-optimal trajectories for cruising aircraft while avoiding the regions of airspace prone to persistent contrails formation. The optimal trajectories are developed by solving a non-linear optimal control problem with path constraints. The regions of airspace favorable to persistent contrails formation are modeled as penalty areas that aircraft should avoid and are adjustable. The tradeoff between persistent contrails formation and additional fuel consumption is investigated, with and without altitude optimization, for 12 city-pairs in the continental United States. Without altitude optimization, the reduction in contrail travel times is gradual with increase in total fuel consumption. When altitude is optimized, a two percent increase in total fuel consumption can reduce the total travel times through contrail regions by more than six times. Allowing further increase in fuel consumption does not seem to result in proportionate decrease in contrail travel times.

Integration of Linear Dynamic Emission and Climate Models with Air Traffic Simulations

“…2 In this study, the regions of airspace that have RHw greater than € r contr and RHi greater than 100% are considered favorable to persistent contrails formation. More details for the contrails prediction model and the weather forecasting system, Rapid Update Cycle (RUC), are provided in a previous paper 16 . This model will be used to compute the regions in the U. S. airspace that facilitate persistent contrails formation.…”

“…The amount of additional fuel consumed in flying a contrail reduction route instead of flying a wind optimal route represents increased cost to the airlines as well as a negative impact on the environment due to the resulting excess CO 2 emissions. Each additional kg of fuel produces approximately 3.15kg of CO 2 .The optimization module in the simulation generates trajectories that reduce travel time through contrail regions by imposing a penalty on travel through potential contrail areas 16 . Three optimal trajectories from Chicago O'Hare airport (ORD) to Newark Liberty airport (EWR), corresponding to three different penalties on the contrail regions, are shown in Fig.…”

Mathematical Models for Aircraft Trajectory Design: A Survey

“…The aircraft trajectory synthesis problem is studied in [76] to provide some basic tools for air traffic automation. Somewhat related is the recent work of Sridhar [77], in which he considered the generation of wind-optimal trajectories for cruising aircraft while avoiding the regions of airspace that facilitate persistent contrails formation. A shooting method was employed to solve the associated optimal control problem by minimizing a weighted sum of flight time, fuel consumption, and a term penalizing the contrail formation.…”

Robust Aircraft Trajectory Planning Under Wind Uncertainty Using Optimal Control

“…Then, an optimal control problem is formulated in order to search for the control sequence that minimizes a probabilistic functional that aggregates the cost among all of the trajectories (see Figure 1.b). Some examples of aerospace applications employing this technique are robust trajectory optimization for an aircraft based on dynamic soaring [17,Chapters 2,3], trajectory optimization for a supersonic aircraft with uncertainties in the aerodynamic data [18] and optimization of a spacecraft reorientation maneuver [16].…”