Cruise Flight Performance Optimization for Minimizing Green Direct Operating Cost

Abstract

To cope with the environmental impact of aviation and pollution problems in the future, airlines need to assess environmental impacts and offer countermeasures in advance. In order to measure the influence of environment on the airlines’ operational costs, this paper establishes an aircraft green direct operating cost (GDOC) model to quantify adverse environmental effects, such as air pollution and greenhouse effects, into the direct operating cost (DOC). Furthermore, fuel consumption, flight time, and distance in the cruising stage account for about 80% of the entire flight mission, and optimizing cruise flight performance can contribute greatly to reduce GDOC. Therefore, this paper sets up an optimal control model to minimize GDOC, establishes a discrete time dynamic system for optimizing the cruise altitude and speed profiles, and searches the optimal results by using dynamic programming. Besides, as meteorological conditions affect aircraft aerodynamics, fuel flow rate, contrail formation, and so on, this paper analyzes meteorological uncertainty by using historic meteorological data. Finally, a route is selected as an example, and the rationality of the optimal results is proven by comparing GDOC with DOC. The results and discussion of the numerical test also show that environmental effects on aircraft operation can be reduced significantly by adopting GDOC as the optimization objective, especially the contrail cost, and the step-climb cruise mode can further reduce GDOC effectively.

Simulation, Optimization, and Machine Learning in Sustainable Transportation Systems: Models and Applications

“…Hence, it is expected that there will be an increase in the application of optimization for sustainable airlines. For example, Tian et al [55] developed a model that optimizes the speed profile and cruising altitude of a flight by taking into account the environmental impact.…”

A Scheme of Sustainable Trajectory Optimization for Aircraft Cruise Based on Comprehensive Social Benefit

“…However, the value of the NO x emission index is affected by the real-time atmospheric conditions and fuel flow rate in addition to the aircraft type, meaning that it will change constantly during operation. erefore, the total NO x emissions, E NO x , should be the integral of emissions at all times as equation (7) shows…”

“…As developed by Hartjes et al [6], it can be achieved by minimizing the flight time in the area where contrails may take place. With the consideration of both CO 2 emissions and contrail formation, Tian et al [7] defined the green direct operating cost (GDOC) and succeeded in obtaining the optimal cruise altitude and speed with the minimum GDOC. e four-dimension (4D) green trajectory optimization was further implemented by their group [8] taking more factors such as NO x emissions and other harmful gases into account.…”

4D Trajectory Optimization of Commercial Flight for Green Civil Aviation

“…Compared with the costs of greenhouse gases, the costs of harmful gases HC, CO, and NO x are more uniform. The calculation formula for the emission costs of harmful gases is proposed by Phleps and Hornung [11]: (35) Cost (36) where Cost HC , Cost CO , and Cost No x are emission costs of HC, CO, and NO x (e),C U = 4 (e/t) is the harmful gas emission cost coefficient and f emission = 15.9% is the percentage of the flights affected by emission charges. Therefore, the model of the harmful gas cost is:…”

“…Hartjes et al developed a tool that optimizes the trajectories of multiple airliners that seek to join in formation to minimize overall fuel consumption or direct operating cost [34]. Tian et al set up an optimal control model to minimize green direct operating cost (GDOC) and established a discrete time dynamic system for optimizing the cruise altitude and speed profiles [35].…”