Aircraft fuselage sizing with multilevel optimization B. Colson, M. Porcelli and Ph. L. Toint naXys TR 07-2013, 3 May 2013 In this technical report we describe the activity research carried out in the years 2010-2012 at Department of Mathematics, University of Namur, Namur (Belgium) in collaboration with LMS Samtech, Angleur (Belgium), in the framework of the project “Methodes de resolution de problemes d’optimisation de grande taille pour les structures en materiaux composites” (Acronym LARGO “LARge-scale Optimization problems”). LARGO was granted by the Walloon Region and LMS Samtech in the context of the First Program (convention number 916981).