"One of the challenges that currently exists for the design of large aircraft structures under natural-laminar-flow (NLF) regime is the extremely high requirements that must be achieved in terms of tolerances with the aim of ensuring that the flow will be sufficiently stable. In systems composed of many parts (such as the Smart Fixed Wing Aircraft torsion box object of study), the assembly processes acquire a special relevance, taking into account that, depending on how they are executed, the tolerances of each part might accumulate and generate deviations much larger than those of the parts taken individually.The objective of the present project is the development of a numerical methodology for theanalysis of the assembly tolerances of aircraft components designed to operate under naturallaminar flow (NLF). The methodology should allow determining the maximum acceptablecomponents deviations to obtain assemblies within the specified tolerances, evaluating theinfluence of the joining techniques and the jigs, and determining the best assembly strategy orbolting sequence. For that, the proposed approach integrates tolerance accumulationtechniques and mechanical/structural tools in order to consider in the analysis the partscompliance and other possible relevant effects associated with the joints."