Sealing system for use in an aircraft device that is to be sealed off from the environment, comprising: - a door element, which is connectable to a housing of the aircraft device and in the state of connection to the housing of the aircraft device is movable between an open position, in which the door element clears a door aperture formed in the housing of the aircraft device, and a closed position, in which the door element closes the door aperture formed in the housing of the aircraft device, - a sealing element, on which a sealing surface is formed, wherein the sealing surface of the sealing element is adapted to interact sealingly with a contact surface when the door element is situated in its closed position, and - a positioning device, which is adapted to move the door element substantially at right angles to the sealing surface of the sealing element or to the contact surface between a first position, in which the sealing surface of the sealing element is not in sealing contact with the contact surface, and a second position, in which the sealing surface of the sealing element is in sealing contact with the contact surface, wherein the positioning device comprises an activating device, which is adapted to exert on the door element a force, by means of which the door element is moved towards the sealing surface of the sealing element or towards the contact surface and the activating device comprises a wedge element, which is fastened to an outer peripheral surface of the door element and adapted to interact with an inner peripheral surface of the door aperture that lies opposite the outer peripheral surface of the door element when the door element is situated in its closed position, characterized in that the activating device further comprises a wedge element, for being fastened to an inner peripheral surface of the door aperture and adapted to interact with an outer peripheral surface of the door element that lies opposite the inner peripheral surface of the door aperture when the door element is situated in its closed position. - a door element, which is connectable to a housing of the aircraft device and in the state of connection to the housing of the aircraft device is movable between an open position, in which the door element clears a door aperture formed in the housing of the aircraft device, and a closed position, in which the door element closes the door aperture formed in the housing of the aircraft device, - a sealing element, on which a sealing surface is formed, wherein the sealing surface of the sealing element is adapted to interact sealingly with a contact surface when the door element is situated in its closed position, and - a positioning device, which is adapted to move the door element substantially at right angles to the sealing surface of the sealing element or to the contact surface between a first position, in which the sealing surface of the sealing element is not in sealing contact with the contact surface, and a second position, in which the sealing surface of the sealing element is in sealing contact with the contact surface, wherein the positioning device comprises an activating device, which is adapted to exert on the door element a force, by means of which the door element is moved towards the sealing surface of the sealing element or towards the contact surface and the activating device comprises a wedge element, which is fastened to an outer peripheral surface of the door element and adapted to interact with an inner peripheral surface of the door aperture that lies opposite the outer peripheral surface of the door element when the door element is situated in its closed position,