NONE 20260722112810414 wseas/wseas content-registration-form@crossref.org content-registration-form International Journal of Applied Mathematics Computational Science and Systems Engineering 2766-9823 Alexandre Mantovani Davanzo Department of Aerospace Federal University of ABC São Bernardo do Campo - SP, 09606-045 BRASIL Liz Carlos Gadelha De Souza Department of Aerospace Federal University of ABC São Bernardo do Campo - SP, 09606-045 BRASIL This work presents the development of software, implemented for Windows using Visual Studio and C#, aimed at estimating the fuel load required for a commercial aircraft prior to departure. The system is based on the operational parameters of the Boeing 777-300ER equipped with GE90-115B engines and allows the user to select departure and destination airports from a database containing major international airports and their respective geographic coordinates. The distance between airports is calculated using the WGS-84 geodetic model, a standard widely adopted in international aviation, ensuring greater accuracy in distance computation. In addition to distance, the system considers operational factors such as onboard weight, mandatory fuel reserves, and other parameters defined by civil aviation safety standards. The application also enables the inclusion of alternate airports and estimates total fuel consumption based on realistic and safe flight scenarios. The results are displayed clearly to the user, serving as a support tool for academic simulations and operational studies. Complementing the software development, the associated monograph conducts a comparative analysis between commercial aircraft from different generations, focusing on fuel efficiency. The comparison involves an older model, predominantly built with aluminium, and a more modern aircraft constructed from composite materials. The analysis highlights performance gains associated with higher cruising altitudes, reduced drag, and lighter structural weight, demonstrating the direct impact of these variables on fuel consumption. 07 22 2026 07 22 2026 134 13 https://creativecommons.org/licenses/by/4.0/deed.en_US 10.37394/232026.2026.8.13 https://wseas.com/journals/amcse/2026/a26amcse-013(2026).pdf Mendonça PTR (2005) Materiais compósitos & estruturas-sanduíche: projeto e análise. Barueri (SP): Manole. International Civil Aviation Organization (2018) Annex 6 to the Convention on International Civil Aviation: Operation of Aircraft. Part I – International Commercial Air Transport – Aero planes. 11th ed. Montreal: ICAO.https://www.icao.int/safety/airnavigati on/NationalityMarks/annexes_booklet_en.pd f.> May 21, 2025. Boeing (2010) Flight Crew Operating Manual – 777-300ER (GE90). Seattle: Boeing. Boeing (2010) Flight Crew Operating Manual – 787 Dreamliner. Seattle: Boeing. Anderson JD (2017) Fundamentals of Aerodynamics. 6th ed. New York: McGrawHill Education. Alexandre MD (2025) Software development for calculation of fuel consumption in commercial aircraft. Undergraduate thesis. São Bernardo do Campo (Brasil): Federal University of ABC.