A system box for accommodating aircraft systems, and for load transmission between an aircraft structure and a crew rest compartment. The system box comprises a first, a second and a third region, wherein the three regions differ from each other. The first region is adapted attachment of the system box to the primary structure of the aircraft, wherein the second region is adapted for mechanical contact with a crew rest compartment for the aircrew. The mechanical contact in turn is adapted for load transmission between the aircraft structure and the crew rest compartment. Necessary aircraft systems are accommodated in the third region of the system box.