Stiffener skeleton for a firewall arrangement of a rotary wing aircraft

1. A stiffener skeleton that is configured to be mounted to an upper deck of a rotary wing aircraft in a maintenance phase, comprising:

an upper stiffening structure with a plurality of supporting arms for providing upside stiffening support; and

a lateral stiffening structure with a plurality of supporting legs for providing lateral stiffening support;

wherein the plurality of supporting arms and the plurality of supporting legs form a self-supporting frame structure; and

wherein the self-supporting frame structure is configured to be arranged in the maintenance phase on a firewall arrangement provided on an upper deck of a rotary wing aircraft for supporting and stiffening at least a front firewall, a rear firewall, and a mid firewall of the firewall arrangement.

2. The stiffener skeleton of claim 1 further comprising mounting means that are configured to be fixedly mounted to an upper deck of a rotary wing aircraft.

3. The stiffener skeleton of claim 2 wherein the mounting means are integrated into the plurality of supporting legs.

4. The stiffener skeleton of claim 1 further comprising lower linking arms that interconnect associated supporting legs of the plurality of supporting legs.

5. The stiffener skeleton of claim 1 wherein the upper stiffening structure is attached to the lateral stiffening structure in an assembled state.

6. The stiffener skeleton of claim 5 , wherein the upper stiffening structure is detachably attached to the lateral stiffening structure in an assembled state.

7. The stiffener skeleton of claim 1 wherein the self-supporting frame structure is foldable.

8. The stiffener skeleton of claim 1 further comprising a plurality of supporting legs connections that detachably attaches the plurality of supporting legs to the plurality of supporting arms in an assembled state of the stiffener skeleton.

9. The stiffener skeleton of claim 8 wherein at least one of the plurality of supporting legs comprises an associated hinge that enables folding of the at least one of the plurality of supporting legs at least in a disassembled state of the stiffener skeleton.

10. The stiffener skeleton of claim 8 wherein at least one of the plurality of supporting arms comprises an associated hinge that enables folding of the at least one of the plurality of supporting arms at least in a disassembled state of the stiffener skeleton.

11. The stiffener skeleton of claim 1 wherein at least one of the plurality of supporting arms comprises an associated hinge that enables folding of the at least one of the plurality of supporting arms in an assembled state of the stiffener skeleton, and wherein each one of the lower linking arms comprises an associated hinge that enables folding of the lower linking arms in the assembled state of the stiffener skeleton.

12. The stiffener skeleton of claim 1 further comprising a plurality of hinges that pivotally connects the plurality of supporting legs to the plurality of supporting arms to enable folding of the plurality of supporting legs toward the plurality of supporting arms in an assembled state of the stiffener skeleton.

13. The stiffener skeleton of claim 1 wherein at least two of the plurality of supporting legs and an associated one of the plurality of supporting arms form a C- or U-shaped skeleton section.

14. The stiffener skeleton of claim 1 wherein a first and a second leg of the plurality of supporting legs and a first supporting arm of the plurality of supporting arms form a front skeleton section, wherein a third and a fourth leg of the plurality of supporting legs and a second supporting arm of the plurality of supporting arms form a rear skeleton section, and wherein a third supporting arm of the plurality of supporting arms connects the front skeleton section to the rear skeleton section.

15. The stiffener skeleton of claim 1 further comprising an extension supporting arm that is connected to one of the plurality of supporting arms.

16. The stiffener skeleton of claim 15 , wherein the extension supporting arm is connected to one of the plurality of supporting arms by means of an associated hinge.

17. The stiffener skeleton of claim 16 , wherein the upper stiffening structure is attached to the lateral stiffening structure in an assembled state and wherein the upper stiffening structure is detachably attached to the lateral stiffening structure in an assembled state.

18. The stiffener skeleton of claim 16 , further comprising an extension supporting arm that is connected to one of the plurality of supporting arms, wherein the extension supporting arm is connected to one of the plurality of supporting arms by means of an associated hinge.

19. A stiffener skeleton configured to be removable mounted to an upper deck of a rotary wing aircraft in a maintenance phase, the stiffening skeleton comprising:

an upper stiffening structure with a plurality of supporting arms for providing upside stiffening support; and

a lateral stiffening structure connected to the upper stiffening structure, the lateral stiffening structure having a plurality of supporting legs for providing lateral stiffening support;

wherein the plurality of supporting arms and the plurality of supporting legs cooperate together to form a self-supporting frame structure configured to be removably arranged in the maintenance phase on a firewall arrangement provided on an upper deck of a rotary wing aircraft for supporting and stiffening a front firewall, a rear firewall, and a mid firewall of the firewall arrangement.

20. The stiffener skeleton of claim 19 further comprising mounting means configured to be fixedly mounted to an upper deck of a rotary wing aircraft, wherein the mounting means are integrated into the plurality of supporting legs, and further comprising lower linking arms that interconnect associated supporting legs of the plurality of supporting legs.