Indirect Effects of Lightning on Aircraft and Rotorcraft

This article discusses issues related to indirect lightning effects on aircraft/rotorcraft. The standard waveforms used for qualifying the vulnerability of a system are introduced, with their frequency spectrum. The identification of the elementary EM coupling phenomenon allows the understanding of the key drivers of the current distribution and field scattering on a complex structure. The system level EM coupling analysis starts with examples of cable- measurements on real aircraft/rotorcraft, from which simple models are derived in order to understand the origin of the resulting waveforms. Various ways of protection are then proposed, ranging from passive to active solutions. Finally, despite limitations, 3D EM modeling is presented as an efficient complement to scale-one tests. The article concludes on the validity of current knowledge on indirect lightning effects  for future aircraft designs.