Conductive thermoplastic ground plane for use in an aircraft

#The present invention relates to ground planes for use on an interior or exterior of metallic or composite cured aircraft skins and methods of forming the same, and more particularly, to a conductive thermoplastic ground plane that facilitates electrical continuity and flexibility.

#A ground plane is an electrically conductive surface that serves as part of an antenna to reflect radio waves from other antenna elements. The ground plane may function as lightening protection, and/or shield to protect electronic equipment, particularly sensitive electronic equipment such as computers, and communications equipment against electromagnetic interference. In the aircraft industry, electromagnetic interference may cause aircraft instruments to malfunction and can result in navigational errors and even the loss of the aircraft. In the past, the metal skin of the aircraft served as the ground plane. However, at least some known aircraft use composite laminates as the skin material to reduce weight. In such cases, the laminate skin itself is no longer electrically conductive and a conductive ground plane may need to be integrated therein.

#At least some known ground planes for use in an aircraft composite skin include embedded structural materials within the composite, such as non-woven fiber mats, which may be heavy and brittle. Additionally, the fiber mats may cause electrical discontinuity at the manufacturing joint between adjacent composite panels. Another known method of introducing a conductive ground plane to nonconductive composite skin is to apply a sprayed-on conductive material, such as a paint, to the surface of the skin. However, such paints are prone to damage and chipping and lose their continuous electrical conductivity where such damage occurs.

#FIG. 1 is a flow diagram of an exemplary aircraft production and service methodology;

#FIG. 2 is a block diagram of an exemplary aircraft;

#FIG. 3 is a schematic diagram illustrating a method of forming an exemplary conductive thermoplastic ground plane for use with the aircraft described in FIG. 2;

#The implementations described herein relate to a plurality of composite skin panels for use for use with an aircraft. More specifically, the aircraft includes a deformable structure, such as the wings or the empennage, and a plurality of skin panels coupled to the deformable structure. In various embodiments, the skin panels may be fabricated from a metallic material, such as aluminum, a composite material, or a combination of metallic and composite materials. In the illustrated embodiment, each skin panel includes at least a laminated composite layer and a ground plane coupled to the composite layer, wherein the ground plane is an electrically conductive elastic thermoplastic. The conductive thermoplastic ground plane is configured to deform in response to a corresponding deformation of the skin panels, fasteners, and structural joints caused by structural loading, flight loads, thermal expansion and contraction, ground handling and other types of aircraft loads which may deform the structure of the aircraft. As such, the ground plane repeatedly accommodates the stresses and strains associated with being coupled to a deformable surface while maintaining its electrical conductivity and without being prone to fatigue damage. In operation, the conductive thermoplastic ground plane minimizes and/or eliminates electrical surface discontinuities such as may be caused by gaps between adjacent skin panels, fasteners, and differences between the conductivities of adjacent skin panels. In some embodiments, the conductive thermoplastic ground plane may be installed over a portion of the aircraft. Optionally, the conductive thermoplastic ground plane may be installed over the entire exterior surface, i.e. the metallic or composite surfaces, of the aircraft to provide a uninterrupted electrically sealed envelope covering the exterior surface of the aircraft. As a result, the conductive thermoplastic ground plane reduces and/or eliminates electrical interference that may occur between various electronic components installed on the aircraft and also functions as a lightning protection device.

#Referring FIG. 1, implementations of the disclosure may be described in the context of an aircraft manufacturing and service method 100 and via an aircraft 102 (shown in FIG. 2). During pre-production, including specification and design 104 data of aircraft 102 may be used during the manufacturing process and other materials associated with the airframe may be procured 106. During production, component and subassembly manufacturing 108 and system integration 110 of aircraft 102 occurs, prior to aircraft 102 entering its certification and delivery process 112. Upon successful satisfaction and completion of airframe certification, aircraft 102 may be placed in service 114. While in service by a customer, aircraft 102 is scheduled for periodic, routine, and scheduled maintenance and service 116, including any modification, reconfiguration, and/or refurbishment, for example. In alternative implementations, manufacturing and service method 100 may be implemented via vehicles other than an aircraft.

#Each portion and process associated with aircraft manufacturing and/or service 100 may be performed or completed by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.