Impact resistant dorsal fin structure of an aircraft being extended along a longitudinal direction X-X' and being symmetric relative to a vertical plane P including the longitudinal direction X-X', the plane P provides two sides A, B on each side of the vertical plane P in the dorsal fin, said dorsal fin is adapted to be arranged on a fuselage of the aircraft and comprises, an upper support at the upper end of the dorsal fin, the upper support comprising a sliding surface (3.1), a ballistic material layer for absorbing high energy impacts, the ballistic material layer comprising a first side (4.1) intended for receiving impacts, said first side (4.1) being arranged on the side A, a second side (4.2) intended for receiving impacts, said second side (4.2) being arranged on the side B and being opposite to the first side (4.1) with respect to the plane P, and an internal surface (4.3) faced to the interior of the dorsal fin; a front frame comprising a substantially planar front edge (5.1), and a rear frame comprising a substantially planar rear edge (6.1), wherein the front frame and rear frame support the ballistic material layer and the upper support, the first side (4.1) of the ballistic material layer comprises a first connecting line, and the opposite side (4.2) comprises a second connecting line, in such a way that the ballistic material layer is adapted to be joined to the fuselage of the aircraft by such connecting lines (1, 2), and the internal surface (4.3) of the ballistic material is in contact with the sliding surface (3.1) of the upper support, and said ballistic material layer is arranged in a sliding manner around the sliding surface (3.1) of the upper support. an upper support at the upper end of the dorsal fin, the upper support comprising a sliding surface (3.1), a ballistic material layer for absorbing high energy impacts, the ballistic material layer comprising a first side (4.1) intended for receiving impacts, said first side (4.1) being arranged on the side A, a second side (4.2) intended for receiving impacts, said second side (4.2) being arranged on the side B and being opposite to the first side (4.1) with respect to the plane P, and an internal surface (4.3) faced to the interior of the dorsal fin; a first side (4.1) intended for receiving impacts, said first side (4.1) being arranged on the side A, a second side (4.2) intended for receiving impacts, said second side (4.2) being arranged on the side B and being opposite to the first side (4.1) with respect to the plane P, and an internal surface (4.3) faced to the interior of the dorsal fin; a front frame comprising a substantially planar front edge (5.1), and a rear frame comprising a substantially planar rear edge (6.1), the front frame and rear frame support the ballistic material layer and the upper support, the first side (4.1) of the ballistic material layer comprises a first connecting line, and the opposite side (4.2) comprises a second connecting line, in such a way that the ballistic material layer is adapted to be joined to the fuselage of the aircraft by such connecting lines (1, 2), and the internal surface (4.3) of the ballistic material is in contact with the sliding surface (3.1) of the upper support, and said ballistic material layer is arranged in a sliding manner around the sliding surface (3.1) of the upper support.