Abstract: An elongate member is coupled by a socket at one end to the aircraft surface, whilst a tip forms its other end. The electrical resistivity of the elongate member, tip and coupling is equal to or greater than 10.sup.2 ohmmeter; and are preferably molded from a high temperature thermoplastics material having an electrical resistivity equal to or greater than 10.sup.16 ohmmeter. The plastics material is selected from the group comprising polyetherimide, polyethersulphone and polyetheretherketone. The material of the tip is provided with an embedded aligned array of carbon or silicone carbide fibers while the other parts of the discharger are loaded with carbon black or coated with the same thermoplastics material loaded with 4% by weight carbon black. The adhesive used to mount the socket has an electrical resistance between 5 to 10K ohms, while that of the socket is between 5 to 10M ohms, that of the elongate member between 20 to 100M ohms, and that of the tip is between 2 to 5 ohms.

Abstract: Lightning strike protection for an aircraft or part of an aircraft is provided by mounting metal (aluminium) rods adjacent but spaced from the inner surface of the aircraft wall. The rods are provided with ball joints from which extensions through the wall stand proud of the aircraft outer surface and within the material of static dischargers. The rods are coupled to bus bar which run the length of the aircraft in turn are coupled to lightning strike dischargers (again in the form of metal rods carried on but spaced from the wall of an aircraft and having extensions which pass through the aircraft wall). The application of the lightning strike protection system to radomes, antennas, pitot tubes carbon fiber reinforced plastics structures is discussed, in the former two cases metal rods being provided to extend in the null field of a device within the radome or the antenna.