Assessing the Shield Termination Approaches in Aircraft Wiring to Against the Lightning Indirect Effects

Abstract

Lightning is a natural phenomenon where high voltages and currents suddenly discharge. It can be caused by clouds themselves, clouds between them, or clouds near the earth. Aircraft are at risk of being struck by lightning and there is currently no way to prevent this from happening. Instead, efforts are being made to protect by reducing the effects of lightning. Metal structures in aircraft form a Faraday cage which helps in preventing lightning currents from entering the aircraft. However, composite structures, which are becoming more prevalent in the aviation sector, are less efficient in doing so compared to metals. Additionally, openings such as windows in the aircraft can break the Faraday cage and allow strong electromagnetic fields to penetrate. Hence, all equipment used on board the aircraft must be adequately qualified and lightning-proof. The most popular technique used to reduce the indirect effects of lightning on electronics is cable shielding. In this study, various shielding termination techniques for their effectiveness against indirect effect of lightning examined and it is found that utilizing a 360 degrees backshell termination technique provided to be highly effective, providing protection of nearly 3 dB. The results obtained from the experiments are compared with simulation results and previous studies.