Numeric lightning protection prediction for wires in an aircraft wing raceway

Measurement or numeric simulation are well known means in the EMC business. Both can give an early idea of the electromagnetic protective performance of a particular design that should be optimized for example to provide for lightning protection. Measurements require hardware; models need to be well understood. This contribution deals with the application of tools for assessing the lightning protection performance during the design phase of an aircraft. The subject of investigation is the protection performance of so-called raceways which are installed inside an aircraft wing. The raceways are extruded aluminum profiles with bays in which the wire bundles are routed. The wire bundles are protected against the lightning impact by the depth of the raceway bays, their minimized exposure along raceway interruptions and the filling level of the bays. All this protection is given by the presence of the conductive aluminum material. On the other hand an optimum design from a weight or mechanic perspective may be achieved with minimal use of material. In order to optimize all design aspects measurements can help but require effort in organization and prototype availability. Full-scale models of an aircraft can be exhaustive but cumbersome when optimizing small scale details. This paper outlines a methodology which avoids these drawbacks by a simplified network model.