Abstract:
A cabin structural segment is provided for an aircraft that includes, but is not limited to a fuselage structure and a floor structure. The fuselage structure defines an interior and separating it from an environment. The fuselage structure includes, but is not limited to an opening for a door. It is possible to provide via the opening a connection between the interior and the environment. The cabin structural segment is designed to be self-supporting. The cabin structural segment is fastenable exclusively to the floor structure. The cabin structural segment is constructed in such a way that the one cabin structural segment frames the opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. 10 2011 102 364.3, filed May 24, 2011 and also priority to U.S. Provisional Patent Application No. 61/489,612, filed May 24, 2011, which are hereby incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The technical field relates to a cabin structural segment for an aircraft. In particular, the technical field relates to a cabin structural segment for an aircraft, which segment is designed to be self-supporting and frames an opening, an aircraft comprising the cabin structural segment, a cabin structural arrangement comprising the cabin structural segment and a cabin structural unit, an aircraft comprising the cabin structural arrangement, and a method for installing the cabin structural segment for an aircraft. 
     BACKGROUND 
     In modern commercial aircraft, cabin built-in elements, for example luggage compartments, lining parts or other interior built-in elements, are fastened directly to an aircraft structure, for example the formers, the stringers or other load-bearing elements of the aircraft fuselage. Owing to a wide range of structural stresses, for example the build-up of a pressure field in the passenger cabin, thermal deformations or flight mechanical loads, the aircraft structure is constantly subject to deformations. These deformations of the aircraft structure inevitably also result in a change in the position of the cabin built-in elements, since these are fastened directly to the structure. 
     In order to counteract these deformations of the aircraft structures and thus the displacements of the cabin built-in elements, in particular the lining parts, longitudinal and radial gaps having a sufficient width, which may for example be between approximately 8 mm and approximately 25 mm, extend between the cabin built-in elements. The door frames and the covers of the boarding regions, in particular, are fastened from many individual components to fastening elements, which are screwed or riveted directly or indirectly to the structure. Production inaccuracies of the individual components and addition of individual tolerances when assembling the individual components make it difficult to attach the door frames and the cover components precisely. For aesthetic reasons, the individual components which face the passenger cabin and can be seen by the passengers must be aligned with one another, since disharmony in the transition from one visible individual component to the adjacent, likewise visible individual component stands out and inevitably results in complaints. The entire door frame and cover assembly in the boarding region is therefore a very complex process and thus a very demanding assembly operation, which is therefore correspondingly time-consuming and thus cost-intensive. 
     DE 10 2006 048 376 discloses a self-supporting cabin structural unit for an aircraft, which unit can be fastened only to a floor structure and can be supported in a moment-free manner on a fuselage structure, the cabin structural unit being designed for attaching cabin built-in elements such as luggage compartments, seat units or step elements. 
     It may be considered at least one object to provide a cabin structure for the door frames and the covers of the boarding regions for a commercial aircraft, in which structure the number of individual components is reduced and the orientation of the individual components is simplified. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background. 
     SUMMARY 
     According to a first embodiment, a cabin structural segment is provided for an aircraft comprising a fuselage structure and a floor structure. The fuselage structure defines an interior and separates the interior from an environment. The fuselage structure comprises an opening for a door, it being possible to provide via the opening a connection between the interior and the environment. The cabin structural segment is designed to be self-supporting. The cabin structural segment can be fastened exclusively to the floor structure. The cabin structural segment is formed in such a way that the one cabin structural segment frames the opening. 
     In this context, fuselage structure is to be understood to mean reinforcing elements of the aircraft fuselage, for example stringers, formers or the outer skin. The floor structure generally has crossbars to which, for example, the rows of seats are fastened in modern commercial aircraft. For their part, the crossbars are usually supported on the formers of the fuselage structure by means of tension-compression rods, known as tie rods. 
     The opening in the fuselage structure is to be understood to mean the opening through which, for example, passengers coming from the gangway enter the aircraft, or rather the interior. This opening can be sealed with an aircraft door. Self-supporting is to be understood to mean that the cabin structural segment does not require further external load-bearing elements in order to fulfil its function. The construction thus supports itself. Thus, all the loads which occur during operation are absorbed centrally in the cabin structural segment. In this case, all the forces and/or moments acting on the cabin structural segment are introduced exclusively into the floor structure. 
     In addition, between the cabin structural segment and the fuselage structure there are no fastening elements which would be used to fasten the cabin structural elements to the fuselage structure. An intermediate space located between the fuselage structure and the cabin structural segment is thus free from fastenings. Owing to the lack of fastening elements of this type between the fuselage structure and the cabin structural segment, forces acting on the fuselage structure, as are produced for example by wind, temperature, pressure differences or other structural movements, are also not transmitted to the cabin structural segment. The cabin structural segment thus forms a unitary, self-supporting static unit, without absorbing deformation forces and/or deformation moments of the fuselage structure. 
     The framing formed in the cabin structural segment may be smaller than, the same size as, or larger than the opening for the door in the fuselage structure, which door is to be opened outwards, that is to say into the environment. Of course, the framing can also be selected in such a way that the door may be opened into the interior. The size of the area framed by the framing may thus not be bound to the size of the opening for the door. Owing to aesthetic and technical considerations, the size of the area framed by the framing will in general basically correspond to the size of the opening in the fuselage structure. 
     Against the background of the aesthetics in particular, an inner lining of the door comprising the cabin structural segment can be formed in such a way that a harmonious overall impression is produced. Owing to the lack of fastening elements between the fuselage structure and the cabin structural segment, cold bridges and structure-borne-noise bridges can be omitted. Equipment holders and structural holders, using which individual panels were previously fastened to the fuselage structure, are also omitted. Individual parts can thus be reduced significantly. 
     Owing to the avoidance of fastening elements and individual panels for constructing the door frames and the covers of the boarding regions, tools for producing the individual parts can be reduced. Owing to the styling of an individual self-supporting cabin structural segment which can be fastened exclusively to the floor structure and when installed frames the opening in the fuselage structure, the assembly is simplified. In addition, reference documentation and management thereof can be reduced. Electric components such as lighting, high channels, cabling or supply units can also be fastened directly to the cabin structural segment. Interfaces, as were previously required between the individual panels, can also be omitted. Interfaces are thus reduced. Overall, the provision of a cabin structural segment of this type results in a significant saving in terms of production and assembly costs. In visual terms, the cabin structural segment can be formed as a free-standing arch which is formed in one piece and through which a passenger can enter the interior of the aircraft. 
     According to a further embodiment, the one cabin structural segment frames two mutually opposing doors. Specifically owing to styling of this type, a separate cabin structural segment is not required for every door. Rather, two mutually opposing openings can be framed in a single cabin structural segment. 
     According to a further embodiment, the one cabin structural segment frames only mutually opposing longitudinal sides of an opening, which extend substantially transverse to the floor structure, and an upper side, opposing the floor structure, of the opening. The opening is thus framed by the one cabin structural segment on three sides, namely at the upper side opposing the floor structure and at the two longitudinal sides of the opening of the cabin structural segment, but not at the side facing the floor structure. Passage through a frame, framing the opening, of the cabin structural segment thus takes place in a sill-free manner. The term sill-free is thus to be understood to mean that the cabin structural segment does not require a frame element which reinforces the cabin structural segment in the region of the floor structure. 
     According to a further embodiment, the cabin structural segment comprises a frame part which frames the upper side, the frame part extending in a screen-like manner towards the fuselage structure. The frame part need not necessarily be straight; it can also be curved, for example. In this case, the frame part can be formed in such a way that it extends as close as possible to the opening for the door in the fuselage structure. This can be achieved for example by guiding the upper side of the frame part which frames the opening as close as possible to the fuselage structure in a screen-like manner. 
     This screen can, for example, be formed parallel to the floor structure. A configuration of this type avoids the possibility that, during flight operation, heat from the passenger cabin may be drawn out towards the cold fuselage structure via a gap that might otherwise be present between the framing of the cabin structural segment and the opening in the fuselage structure, despite the door being closed. This may result in an airstream from the passenger cabin towards the opening, or rather the door. Of course, for improved thermal insulation, the cabin structural segment can comprise a sealing element which can be connected to the fuselage structure. However, this insulating element may be designed in such a way that it cannot transmit any forces between the fuselage structure and the cabin structural segment. The insulating element can also be constructed in a noise-reducing and heat-insulating manner. Of course, frame parts which frame the longitudinal sides of the opening can also be brought as close as possible to the opening. 
     According to a further embodiment, the cabin structural segment comprises an arch segment and a cover segment, the arch segment extending substantially along an inner face of the fuselage structure from the floor structure to the cover segment. The cover segment is spaced apart from the floor structure. The arch segment and the cover segment are rigidly interconnected. The cover segment can also be formed in such a way that it also extends substantially along an inner face of the fuselage structure. However, this cover segment can also be planar, in such a way that it extends substantially parallel to the floor structure. In a configuration of this type in particular, a space is produced between the cabin structural segment, or rather the cover segment, and the fuselage structure, in which space aircraft components can be accommodated such that they are not visible to passengers. The cover segment and the arch segment can be formed in one piece. The cover segment can be spaced so far apart from the floor structure that there is sufficient spacing between a standing passenger and this cover segment. 
     According to a further embodiment, the cover segment comprises an outer face, the outer face being adjacent to the fuselage structure. An electric unit for supplying a passenger cabin with power can be fastened to the outer face. In this case, the electric unit for the power supply can be mounted in the interior either before or after the assembly of the cabin structural segment. The electric unit is formed in such a way that, if the electric unit is mounted on the outer face of the cover segment and is thus not visible to passengers, the electric unit is not additionally fastened to the fuselage structure. 
     According to a further embodiment, the cabin structural segment can be divided substantially centrally in the aircraft longitudinal direction, such that a first cabin structural segment and a second cabin structural segment are formed. A configuration of this type makes it possible on one hand for the cabin structural segment to be produced more easily and also handled more easily by the producer. On the other hand, a division of the cabin structural segment makes it possible for the cabin structural segment produced in cabin structural subsegments to be inserted into a fully assembled fuselage structure through the opening in the fuselage structure to the interior, positioned on the floor structure and orientated relative to the opening in the fuselage structure more easily than a cabin structural segment produced in one piece. 
     After positioning and orientation, the two cabin structural subsegments can be interconnected. In this case, too, the cabin structural segment made up of the first and the second cabin structural subsegment does not comprise any fastening elements with regard to the fuselage structure; rather, it is fastened only to the floor structure. The division can also offer the advantage that less space is required to put up the cabin structural subsegments within the fuselage structure than would be the case for a cabin structural segment produced in one piece. 
     According to a further embodiment, the first and the second cabin structural segment are formed so as to be identical. This can result in a saving with regard to the production and tool costs. Styling of this type also reduces the variety of the individual parts. 
     According to a further embodiment, the cabin structural segment comprises at least one transition segment in the aircraft longitudinal direction, the transition segment being rigidly connected to the cabin structural segment. In particular, the transition segment, which extends towards the lining parts of the passenger cabin, can be formed in such a way that an inner face, facing the passenger cabin, of the transition segment follows an inner contour formed by the lining parts. Thus, a passenger will not perceive the cabin structural segment as a separate component within the overall styling of the passenger cabin. It is also possible to construct the passenger cabin in the region of the windows using individual panels according to the prior art and only construct the boarding region comprising the self-supporting cabin structural segment using the transition segment. Of course, the transition segment can also accommodate seats, doors for toilet facilities or storage compartments. 
     According to a further embodiment, an aircraft is provided comprising a cabin structural segment of this type. According to a further embodiment, a cabin structural arrangement for an aircraft comprising a fuselage structure and a floor structure is provided, it being possible to connect the cabin structural segment in the aircraft longitudinal direction to a cabin structural unit for attaching cabin built-in elements for an aircraft. The cabin structural unit is arranged in such a way that a cabin built-in element can be attached. The cabin structural unit is formed so as to be self-supporting. The cabin structural unit can be fastened only to the floor structure. The cabin structural unit can be supported on the fuselage structure in a moment-free manner. 
     The cabin structural segment can thus be connected to a cabin structural unit as described in DE 10 2006 048 376. Of course, an insulating element can be inserted between the cabin structural segment and the cabin built-in element in order on one hand to compensate possible production tolerances of the cabin structural segment and/or the cabin structural unit. On the other hand, the insulating element can be used so as not to transmit forces applied to the cabin structural unit, which might result in deformation of the cabin structural unit, to the cabin structural segment. 
     According to a further embodiment, an aircraft is provided comprising a cabin structural arrangement of this type. 
     According to a further embodiment, a method for installing a cabin structural segment for an aircraft comprising a fuselage structure and a floor structure is provided, the fuselage structure defining an interior and separating it from an environment. The fuselage structure comprises an opening for a door, it being possible to provide via the opening a connection between the interior and the environment. The method comprises the following steps: pre-assembling the cabin structural segment in the environment of the fuselage structure, guiding the pre-assembled cabin structural segment through the opening of the fuselage structure into the interior, positioning the pre-assembled cabin structural segment at a predetermined location in the interior in such a way that the at least one opening is framed by the cabin structural segment, and fastening the cabin structural segment exclusively to the floor structure, the cabin structural segment being formed so as to be self-supporting. The method steps may relate mainly to the installation of a cabin structural segment produced in one piece. 
     According to a further embodiment, a method for installing a cabin structural segment for an aircraft comprising a fuselage structure and a floor structure is provided, the fuselage structure defining an interior and separating it from an environment. The fuselage structure comprises an opening for a door, it being possible to provide via the opening a connection between the interior and the environment. The method comprises the following steps: pre-assembling the cabin structural segment in the environment of the fuselage structure, dividing the pre-assembled cabin structural segment into a first and a second cabin structural subsegment in the environment, guiding the first and the second cabin structural subsegment through the opening of the fuselage structure into the interior, positioning the first and the second cabin structural subsegment at a predetermined location in the interior in such a way that the at least one opening is framed by the first and/or the second cabin structural subsegment, assembling the first and the second cabin structural subsegment to form the cabin structural segment, and fastening the cabin structural segment exclusively to the floor structure, the cabin structural segment being formed so as to be self-supporting. 
     It is noted that embodiments are described herein in connection with a cabin structural segment, an aircraft comprising a cabin structural segment, a cabin structural arrangement, an aircraft comprising a cabin structural arrangement, and a method for installing a cabin structural segment. In this context, it is clear to a person skilled in the art that the individual features described can be combined with one another in a variety of ways in order thus also to arrive at other embodiment configurations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention are described below with reference to the appended figures, which are merely schematic and are not to scale, and: 
         FIG. 1  is a 3D side view of a cabin structural segment; 
         FIG. 2  is a further 3D side view of the cabin structural segment from  FIG. 1 ; 
         FIG. 3  is a 3D plan view of the cabin structural segment from  FIG. 1 ; 
         FIG. 4  is a 3D side view of a cabin structural arrangement comprising the cabin structural segment from  FIG. 1  and a cabin structural unit; 
         FIG. 5  is a 3D side view of a first cabin structural subsegment; 
         FIG. 6  is a 3D side view of a cabin structural segment comprising a transition segment and an electric unit rigidly connected to the cabin structural segment; 
         FIG. 7  shows a cabin structural arrangement comprising the cabin structural segment from  FIG. 6  and a cabin structural unit; 
         FIG. 8  is a plan view of the cabin structural arrangement from  FIG. 7 ; 
         FIG. 9  is a 3D representation of a cross-section through a fuselage structure of an aircraft, in which fuselage structure a first cabin structural subsegment has been inserted into an interior through an opening for a door; 
         FIG. 10  is a further 3D representation of a cross-section through a fuselage structure of an aircraft, the first cabin structural subsegment from  FIG. 9  having been positioned at a predetermined location on a floor structure; and 
         FIG. 11  is a further 3D representation of a cross-section through a fuselage structure of an aircraft, the first or the second cabin structural subsegment from  FIG. 10  framing the opening for a door. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description. 
       FIG. 1  to  FIG. 3  show a cabin structural segment  2  comprising an arch segment  4  and a cover segment  6 , the representation of the cabin structural segment  2  in the individual figures differing merely in terms of the views. In this case, the arch segment  4  and the cover segment  6  are rigidly interconnected.  FIG. 1  also shows a centre plane  8  which extends parallel to an aircraft longitudinal direction X which is represented by a double arrow. In this case, the centre plane  8  divides the cabin structural segment  2  into a first cabin structural subsegment  10  and a second cabin structural subsegment  12 . 
     The first cabin structural subsegment  10  is mirror-symmetrical to the second cabin structural subsegment  12 . In the representation selected in this case, the first cabin structural subsegment  10  and the second cabin structural subsegment  12  are each formed in one piece. The representation selected in this case shows both a cabin structural segment  2  formed in one piece and a cabin structural segment  2  made up of the first cabin structural subsegment  10  and the second cabin structural subsegment  12 . 
     Each cabin structural subsegment  10 ,  12  and the cabin structural segment  2  formed in one piece are each designed to be self-supporting. The arch segment  4  extends substantially along a fuselage structure (not shown in this case) of an aircraft. The cover segment  6  is formed substantially parallel to a floor structure (also not shown in this case) of an aircraft. The cabin structural segment  2  has, in the region of the arch segments  4  thereof, a respective opening  14 , the two openings  14  opposing one another. The individual elements are described below merely in connection with the first cabin structural subsegment  10 , since this is more visible. The representation selected in this case also applies for the second cabin structural subsegment  12  and for the cabin structural segment  2  formed in one piece. 
     The opening  14 , which is shown in the first cabin structural subsegment  10  and basically corresponds to an opening (not shown in this case) for a door in a fuselage structure, is defined by two frame longitudinal profiles  16  and a frame part  22  in the form of a frame transverse profile. The two frame longitudinal profiles  16  and the frame transverse profile  22  are components of the arch segment  4  and are accordingly formed in one piece with the first cabin structural subsegment  10 . Each frame longitudinal profile  16  extends from a first end  18  of the frame longitudinal profile to a second end  20  of the frame longitudinal profile. The first end  18  of each frame longitudinal profile can be rigidly connected to a floor structure (not shown in this case). The second end  20  of each frame longitudinal profile ends at the frame transverse profile  22  and is rigidly connected thereto. 
     The frame transverse profile  22  extends in a screen-shaped manner and substantially parallel to the floor structure in the direction of the fuselage structure. The cabin structural segment  2  also has, at its sides which extend transverse to the aircraft longitudinal direction X, a peripheral edge  23 . The cabin structural segment  2  thus forms a U-shaped cross-section when looking towards the centre plane  8 . The peripheral edge  23  can also coincide with one frame longitudinal profile  16  or the two frame longitudinal profiles  16 . In the embodiment shown in this case, the frame longitudinal profile  16  is spaced apart from the peripheral edge  23 . 
     In particular when using CFRP materials, very stabile and very light constructions are possible, and widths B of a few millimetres between an outer face, facing the opening  14 , of the frame longitudinal profile  16  and an outer face, opposite the outer face of the frame longitudinal profile, of the adjacent peripheral edge  23  are therefore sufficient for self-supporting styling. It can also clearly be seen that the two frame longitudinal profiles  16  do not comprise a connecting element, for example in the form of a sill, connecting the two frame longitudinal profiles  16  in the vicinity of the floor structure and thus in the region of the first ends  18  of the two frame longitudinal profiles. A sill-less passage through the opening  14  of the cabin structural segment  2  is thus possible for passengers. 
       FIG. 4  is a 3D side view of a cabin structural arrangement  25  comprising the cabin structural segment  2  already known from  FIGS. 1 to 3  and a cabin structural unit  24 . In this case, the cabin structural unit  24  is rigidly connected to the cabin structural segment  2  in the aircraft longitudinal direction X. The cabin structural segment  2  can be made in one piece or assembled from the first  10  and the second cabin structural subsegment  12 . On each side along the aircraft longitudinal direction X the cabin structural unit  24  has an indentation  26  for receiving cabin built-in elements in the form of overhead storage compartments (not visible in this case). The cabin structural unit  24  is also formed so as to be self-supporting. In this case, ends  30  of the cabin structural unit  24  are fastened only to the floor structure (not shown in this case). The elements which can be used to support the cabin structural unit  24  on the fuselage structure in a moment-free manner are not shown on an outer face  32 , facing the fuselage structure, of the cabin structural unit  24 . 
     In contrast thereto, an outer face  34 , facing the fuselage structure, of the cabin structural segment  2  has no elements which may be used to connect the cabin structural segment  2  to the fuselage structure. The outer face  34  also has no elements which may be used to support the cabin structural segment  2  on the fuselage structure. The cabin structural unit  24  also has openings  28  for windows of the aircraft. 
       FIG. 5  shows the first cabin structural subsegment  10 . In contrast to the representations of  FIGS. 1 to 3 , in this case the cabin structural segment  2  has been divided mechanically along the centre plane  8  in the aircraft longitudinal direction X into the first  10  and the second cabin structural subsegment  12 , only the first cabin structural subsegment  10  being shown in this case. Otherwise, the configuration of the cabin structural subsegment  10  is no different from the representation of  FIG. 1  to  FIG. 3 . 
       FIG. 6  is a 3D side view of the cabin structural segment  2  comprising a transition segment  36  and an electric unit  40  which is rigidly connected to the outer face  34  of the cabin structural segment  2 . In this case, the electric unit  40  for distributing power into a passenger cabin extends along the aircraft longitudinal direction X. Of course, the electric unit  40  can also be arranged transverse to the aircraft longitudinal direction X. The transition segment  36  is rigidly fastened to the cabin structural segment  2 . The transition segment  36  can also be formed in one piece with the cabin structural segment  2 . The transition segment  36  has indentations  26  in which storage compartments of the cabin structural unit  24  can be arranged. The electric unit  40  is connected only to the cover segment  6  of the cabin structural segment  2  and has no fastening to the adjacent fuselage structure. The electric unit  40  also does not hinder the self-supporting structure of the cabin structural segment  2  in such a way that connections to the fuselage structure would then be necessary. 
       FIG. 7  shows the cabin structural arrangement  25  comprising the cabin structural segment  2  comprising the transition segment  36  from  FIG. 6  and the cabin structural unit  24  already known from  FIG. 4 . A damping element  42  is arranged at an interface  41  between the transition segment  36  and the cabin structural unit  24 . At the interface  41  the transition segment  36  is also formed in accordance with the cabin structural unit  24 , in such a way that an inner face  43 , facing the passenger cabin, of the cabin structural unit  24  and an inner face  45 , likewise facing the passenger cabin, of the transition segment  36  produce an aesthetic overall impression. In the embodiment shown in this case, the inner face  43  of the cabin structural unit  24  transitions smoothly into the inner face  45  of the transition segment  36 . 
       FIG. 8  is a plan view of the cabin structural arrangement  25  from  FIG. 7 . It can clearly be seen how small the width B of the frame longitudinal profile  16  and of the peripheral edge  23  is, in the selected embodiment the edge  23  transitioning into the frame longitudinal profile  16  and continuously having the width B. The width is selected from approximately 2 to approximately 5 mm. 
       FIG. 9  is a 3D representation of a cross-section through an aircraft fuselage  44 . The fuselage structure  46  and the floor structure  48  are clearly visible. The fuselage structure  46  basically consists of formers  50 , stringers (not shown in this case) and an outer skin  52 . The fuselage structure  46  also has two mutually opposing openings  54  which can be sealed by means of doors (not shown in this case) which open into an environment  58 . The opening  54  is defined by longitudinal sides  62  of the opening, which oppose one another and extend substantially transverse to the floor structure  48 , and an upper side opposite the floor structure  48 . The fuselage structure  46  defines an interior  56  and separates it from the environment  58 . A passenger wishing to enter the aircraft passes from the environment  58  into the interior  56  through the opening  54 , for example via a gangway. The interior  56  can thus be connected to the environment  58  via the sealable opening  54 . 
     The floor structure  48  mainly has crossbars  51  which extend transverse to the aircraft longitudinal direction X and are supported on the formers by means of tension-compression rods  53 . A portion of the interior  56  is equipped with cabin structural units  24 , the inner faces  43  of which define the passenger cabin. It can clearly be seen that the ends  30  of the cabin structural unit  24  are connected to the floor structure  48 . Overhead storage compartments  60  are already mounted on the cabin structural units  24 . To facilitate handling, the cabin structural segment  2  is divided into the first  10  and the second cabin structural subsegment  12 , only the first cabin structural subsegment  10  already known from  FIG. 5  being shown in this case. The first cabin structural subsegment  10  has been displaced from the environment  58  into the interior  56  through the opening  54  of the fuselage structure  46 . It can clearly be seen that the first cabin structural subsegment  10  is wider than the opening  54 , and the first cabin structural subsegment  10  was therefore guided on end through the opening  54 . 
       FIG. 10  differs from the representation of  FIG. 9  in that the first cabin structural subsegment  10  has been displaced from its upended position in such a way that the first ends  18  of the frame longitudinal profiles and thus the first cabin structural subsegment  10  were then positioned at a predetermined location in the interior  56 , or rather on the floor structure  48 . 
       FIG. 11  differs from the representation of  FIG. 10  in that the first cabin structural subsegment  10  has been displaced into its final position. For the sake of clarity, the second cabin structural subsegment  12  is not shown. The second cabin structural subsegment would also be fastened to the floor structure and, together with the first cabin structural subsegment  10 , would form the self-supporting cabin structural segment  2 . It is self-evident that the two cabin structural subsegments  10 ,  12  are also each formed so as to be individually self-supporting. It can clearly be seen that the first cabin structural subsegment  10  and thus also the cabin structural segment  2  frame the opening  54  of the fuselage structure  46 . 
     In particular, the two frame longitudinal profiles  16  frame the longitudinal sides  62  of the opening and the frame transverse profile  22  frames the upper side  64  of the opening  54 . It can also be seen that the two frame longitudinal profiles  16  and the frame transverse profile  22  are formed in such a way that a gap S between the cabin structural segment  2  and the fuselage structure  46 , which gap extends around the two frame longitudinal profiles  16  and the frame transverse profile  22 , is minimal. 
     In particular owing to the styling of the very narrow gap S between the fuselage structure  46  and the frame transverse profile  22 , a situation can be avoided in which, during flight operation, heat from the subsequent passenger cabin would be drawn out to the cold fuselage structure  46  via a gap which might otherwise be present in a wider form between the frame transverse profile  22  of the cabin structural segment  2  and a closed lined door. This would result in a draught in the region of the openings  54 , and this may impact on the comfort of passengers sitting in the vicinity of the opening  54 . 
     The configuration of the cabin boarding module as a self-supporting cabin structural segment  2  makes it possible to omit cold bridges and structure-borne-noise bridges owing to the lack of connecting elements between the cabin structural segment  2  and the fuselage structure  46 . Equipment holders and structural holders are also omitted. The number of individual parts is also reduced, and this in turn results in a reduction in tools and a reduction in reference documentation and the management thereof. The assembly is also greatly simplified. In addition, electric components such as high channels, cabling or other electric, pneumatic or hydraulic devices can be arranged directly at the cabin structural segment  2 . Interfaces are also reduced, in that the plurality of lining panels required to construct the boarding module has been reduced to a single cabin structural segment  2 . This also results in significant savings in terms of production and assembly costs. 
     In addition, it should be noted that “comprising” does not exclude any other elements or steps and that “a” or “an” does not exclude a plurality. It should also be noted that features or steps which have been described with reference to one of the above embodiments can also be used in combination with other features or steps of other embodiments described above. Moreover, while at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.