Method of repairing an aircraft structure component

1. A method of repairing an aircraft structural component, which has a component fault in a portion adjoining a cavity of the aircraft structural component, wherein the method comprises the following steps:

removing a region of the aircraft structural component that has the component fault,

introducing an expansion body comprising a balloon made of a heat-resistant expandable plastics material into the cavity of the aircraft structural component through an opening that has been formed in the aircraft structural component by the removal of the region of the aircraft structural component that has the component fault, wherein the expansion body while being introduced into the cavity of the aircraft structural component is in a non-expanded state,

converting the expansion body that has been introduced into the cavity of the aircraft structural component to an expanded state such that the expansion body in its expanded state fills the cavity to an extent that it exerts a first pressure on an inner surface of the aircraft structural component that faces the cavity and completely overlaps the opening, and

closing the opening by means of a repair material,

wherein during closing of the opening by means of the repair material the expansion body in its expanded state exerts the first pressure on the inner surface of the repair material that faces the cavity of the aircraft structural component, and the expansion body is converted to its expanded state by introducing a self-hardening foam material into the expansion body.

2. The method according to claim 1 , characterized in that during closing of the opening by means of the repair material a second pressure is exerted on an outer surface of the repair material that faces away from the cavity of the aircraft structural component.

3. The method according to claim 2 , characterized in that the first pressure, which during closing of the opening by means of the repair material is exerted by the expansion body in its expanded state on the inner surface of the repair material facing the cavity of the aircraft structural component, corresponds in value substantially to the second pressure, which during closing of the opening by means of the repair material is exerted on the outer surface of the repair material that faces away from the cavity of the aircraft structural component.

4. The method according to claim 1 , characterized in that the self-hardening foam material is introduced into the expansion body by means of a lance, which during introduction of the self-hardening foam material into the expansion body projects through the opening into the cavity of the aircraft structural component.

5. The method according to claim 4 , characterized in that after hardening of the foam material the lance is removed from the expansion body.

6. The method according to claim 1 , characterized in that the region of the aircraft structural component that has the component fault is removed in steps.

7. The method according to claim 1 , characterized in that the opening is closed by means of a plurality of superimposed repair material layers.

8. The method according to claim 7 , characterized in that an inner repair material layer that adjoins the cavity of the aircraft structural component has a smaller area than an outer repair material layer that faces away from the cavity of the aircraft structural component.