Abstract: An external part of an aircraft (such as a fairing) comprising a skin made with flexible materials attached to rigid supporting elements (such as longerons and frames) arranged in, at least, two directions. The skin comprises inner inflatable panels in all bays delimited by the rigid supporting elements and/or an external inflatable panel. The skin is joined to the supporting elements so that its external surface complies with aerodynamic requirements.

Abstract: The present disclosure refers to a multi-spar torsion box structure comprising a plurality of spars of composite material arranged to form a multi-cell structure with two or more cells extending span-wise at the torsion box, and upper and lower skin covers of composite material respectively joined to upper and lower surfaces of the multi-cell structure. The structure further comprises at least one belt-like reinforcing element extending on the outer perimeter of the torsion box, and fixed to the upper and lower surfaces of the multi-cell structure, and transversely arranged with respect to the span-wise direction of the torsion box. The belt-like reinforcing element is made of a metallic or a composite material. The present disclosure can advantageously be used in the manufacture of aircrafts lifting surfaces, such as horizontal tail planes (HTP) or wings.