the exemplary embodiment shown in the figures of an aircraft fuselage structure 1 according to the disclosure herein extends along a longitudinal axis x and has a substantially round cross section . the fuselage structure 1 is provided with an outer skin 3 which is formed from aluminium sheet elements and which surrounds the internal space of the structure . if directions are referred to below , the usual coordinate system in aircraft design and illustrated in fig1 is used , wherein the x - direction extends parallel to the longitudinal axis x and from front to back . the y - direction extends parallel to the plane of the support surfaces and perpendicular to the x - direction . finally , the z - direction faces downwards perpendicular to the x - direction . the outer skin 3 is retained on the side facing the internal space by a plurality of circumferential ribs 5 which are at intervals from one another and which extend in planes perpendicular to the longitudinal axis x along the outer skin 3 . as may be further seen from fig1 , 2 and 3 , in the upper region , symmetrically about a vertical longitudinal central plane 6 extending through the longitudinal axis x , the fuselage structure 1 has a recess 7 which is defined by longitudinal edges 9 extending parallel to the longitudinal axis x and transverse edges 11 extending transversely thereto . the recess 7 thus extends in this exemplary embodiment symmetrically away from the highest point of the fuselage structure 1 on both sides . this recess 7 is provided for receiving a wing torsion box , not shown in the figures , which serves to connect the support surfaces , also not shown , to one another and to the fuselage , and additionally to absorb the wing moments , i . e . m x due to the wing bending about the flight axis , m y due to the wing torsion and m z due to moments about the vertical axis as a result of the air resistance . the connection of the wing torsion box permits the reduction of the moments as force pairs . the wing torsion box may extend in the z - direction into the fuselage through the recess 7 in the fuselage structure 1 so that , as a result , the aforementioned advantages of a high - wing plane produce less air resistance , etc . the transverse edges 11 of the recess 7 are formed by crossmembers 13 extending in a linear manner , the crossmembers being arranged such that in the region of the vertical longitudinal central plane 6 of the fuselage structure 1 they are spaced apart from the outer skin 3 in the vertical direction ( see fig2 ). as is visible in particular from fig3 , the recess 7 extends in the direction of the longitudinal axis x across a plurality of ribs 5 ′ from the front transverse edge 11 to the rear transverse edge 11 , wherein the ribs 5 ′ are interrupted by the recess 7 and thus do not extend over the upper region of the fuselage structure 1 . along the longitudinal edges 9 of the recess 7 first longitudinal members 15 initially extend immediately adjacent to the recess 7 . the longitudinal members 15 in this case extend over the entire length of the recess 7 and the end regions 17 thereof extend beyond the recess 7 , viewed in the direction of the longitudinal axis x . in this case , the end regions 17 of the first longitudinal members 15 are fixedly connected to those ribs 5 which extend circumferentially at intervals from the transverse edges 11 and / or the crossmembers 13 along the outer skin 3 and extend across the vertical longitudinal central plane 6 ( see fig3 , 4 , and 5 ), viewed in the longitudinal direction x . in this case , the first longitudinal members 15 are also connected to the crossmembers 13 . in addition to the first longitudinal members 15 , second longitudinal members 19 extending parallel and at intervals therefrom are provided in the fuselage structure 1 , wherein the second longitudinal members 19 extend on the side of the first longitudinal members 15 remote from the recess 7 . the second longitudinal members 19 also extend beyond the length of the recess 7 , viewed in the x - direction , and the end regions 21 are fixedly connected to ribs 5 which fully extend over the circumference of the fuselage structure 1 , and thus also extend in the region of the vertical longitudinal central plane 6 . the free ends 23 of the ribs 5 ′ facing the recess 7 , which do not extend over the full circumference of the fuselage structure 1 are fixedly connected to the first longitudinal members 15 ( see fig5 ). the ribs 5 ′ extend through the second longitudinal members 19 and / or across said longitudinal members , wherein tabs are used for connecting the rib portions across the second longitudinal members 19 . the ribs 5 ′ thus have rib portions 24 between the first and the second longitudinal members 15 , 19 , the rib portions extending perpendicular thereto and connecting the first and the second longitudinal members 15 , 19 together . moreover , the free ends 25 of two ribs 5 ′ in the region of the recess 7 have first retaining tabs 27 which extend through corresponding recesses 29 in the first longitudinal members 15 towards the recess 7 ( see fig4 and 5 ). the first retaining tabs 27 serve to couple the first longitudinal members 15 to the wing torsion box , not shown , to absorb loads . additionally , the first retaining tabs 27 may be connected to corresponding pendulum supports . in addition , the second longitudinal members 19 have second retaining tabs 31 for coupling the support surfaces , wherein the second retaining tabs 31 extend to the outside through the outer skin 3 and may also be connected to pendulum supports ( see fig1 and 3 ). in order to introduce the forces absorbed by the longitudinal members 15 , 19 and extending in the direction of the longitudinal axis x in the upper portion of the fuselage structure 1 extending in the vicinity of the vertical longitudinal central plane 6 , oblique portions 33 are provided on the outer skin 3 , the oblique portions starting from crossmembers 13 extending along the transverse edges 11 of the recess 7 , so that the oblique portions 33 connect the crossmembers 13 to the ribs 5 of the outer skin 3 ( see fig7 to 9 ). such oblique portions 33 are provided at both ends and / or both at the front and at the rear transverse edge 11 . the oblique portions 33 extend in planes which are inclined relative to the longitudinal axis x and which slope away from the outer skin 3 towards the crossmembers 13 . moreover , rib elements 35 are provided on the inwardly facing side of the oblique portions 33 , the rib elements extending perpendicular to the crossmembers 13 towards the ribs 5 of the outer skin 3 ( see fig7 and 9 ). to this end , on the ribs 5 which extend immediately adjacent to the recess 7 , additional members 37 extending at an angle thereto are provided , the additional members extending along the connecting line 39 between the oblique portions 33 and the outer skin 3 , and the ends thereof facing the center of the fuselage are connected to the adjacent rib 5 . the inclined path of the additional members 37 relative to the ribs 5 , together with the rib 5 to which the additional members 37 are connected , combine to produce a horseshoe - shaped path . as the oblique portions 31 extend in an inclined plane and the outer skin 3 , in particular in the upper region of the fuselage structure 1 , has a substantially circular cross section , a connecting line 39 extending in a curved manner is produced in each case between the outer skin 3 and the oblique portion 33 . in order to strengthen further the connection between the oblique portions 33 and the rib elements 35 , strut elements 41 are provided between the additional members 37 and the rib elements 35 , the strut elements connecting both together . by the construction of the fuselage structure 1 with the first and second longitudinal members 15 , 19 extending in each case on both sides of the recess 7 parallel to one another , which , as is revealed from fig1 and 2 , in addition to the connection to the ribs 5 extending on the other side of the recess 7 , are also fixedly connected to the crossmembers 13 , the loads which are otherwise absorbed by the upper portion of the fuselage structure 1 are forwarded in the vicinity of the vertically extending longitudinal central plane 6 around the recess 7 . this is additionally assisted by the path of the oblique portions 33 , the connection thereof to the crossmembers 13 as well as the additional members 37 extending at an angle . thus it is ensured that the forces are introduced into the upper portion of the outer skin 3 . moreover , the region around the recess 7 is also particularly stabilized as the first and second longitudinal members 15 , 19 provided on both sides of the recess 7 form “ torsion boxes ” with the outer skin 3 and the ribs 5 , 5 ′ connecting the longitudinal members 15 , 19 . the support surfaces are received thereon via the first retaining tabs 27 , 31 , so that the loads thus produced are introduced via said “ torsion boxes ” into the fuselage . with the design according to the subject matter herein of a fuselage structure 1 , it is thus possible to forward forces in the longitudinal direction absorbed in the upper portion thereof around the recess 7 for the wing torsion box , without it being necessary to provide supports or the like extending over the length of the recess 7 .