Identification and Validation of an Aircraft Performance Model for the Study of Flight Trajectories of the Cessna Citation X

Abstract

Flight trajectories optimization has been identified as one of the solutions to reduce fuel consumption, and carbon footprint of aircraft in the short term. To be able to analyze and optimize aircraft flight trajectories, it is necessary to develop mathematical models capable of predicting aircraft performance with great accuracy. Within this context, the main goal of this thesis was to propose different techniques to identify a mathematical model of an aircraft, and to predict the trajectories and flight performance of an aircraft. The studies presented in this thesis were carried out in collaboration with the LARCASE industrial partners, and were applied on the well-known Cessna Citation X business jet for which a highly qualified research aircraft flight simulator was available. The first part of this thesis focused on the identification and creation of a mathematical model of the Cessna Citation X based on data published in the aircraft flight manuals (or equivalent source). The objective of this mathematical model was to represent the aerodynamic and propulsive performance of the aircraft. Two approaches were then considered. The first approach consisted of identifying a propulsion model of the aircraft assuming that the data published in the flight manuals included sufficiently relevant information regarding the engine performance. The second approach assumed that no engine information was available, and that only flight trajectories data was accessible to the user. In both approaches, it was possible to obtain a mathematical model of the aircraft that was both reliable and accurate. The second part of this thesis focused on the study and prediction of aircraft flight trajectories. A mathematical model of the aircraft, different algorithms have been developed to predict the performance, and flight trajectories of the Cessna Citation X. Once again, this study was divided into two subparts; the first subpart was devoted to the takeoff phase study, while the second subpart was devoted to the portion of the flight above 1500 feet (i.e., excluding the takeoff and landing phases). The algorithms and techniques proposed in this thesis made it possible to account for the effects of the wind, but also to take into account the piloting techniques. Finally, the last part of this thesis focused on the monitoring of the aircraft performance, and on the automatic update of the mathematical model of the aircraft. For this purpose, an algorithm to analyze the aircraft performance in cruise was developed. This algorithm allowed, in a first step, to collect various aircraft flight parameters and to perform different analyses to identify the flight segments in which the aircraft was in trim conditions. Once these flight segments were identified, the algorithm correlated the measured flight parameters with those predicted by the aircraft mathematical model. This analysis was then used to assess the accuracy of the aircraft mathematical model. If the model was no longer accurate, then its automatic update was performed. The combination of all the studies presented in this thesis has allowed the design of mathematical tools for the study, analysis and prediction of the flight trajectories of the Cessna Citation X aircraft. These tools were developed to meet specific needs of the aeronautical industry, but also to help LARCASE researchers in their research.

Date	11 Nov 2020
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Ruxandra Botez (Supervisor)