An introduction to a new aerospace lightning direct effects research programme and the significance of Zone 2A waveform components on sparking joints

PROTEST is the name of a new UK based aerospace lightning direct effects research program with the principal purpose of researching the lightning direct effects of structural aircraft fuel tank joints. It is particularly focused on understanding the out-gassing phenomena and its relationship with the various design parameters of composite structures. Early activity within the project investigated the waveform components that are of most relevance to future studies. The paper documents the findings of this early activity. It was found that the D-component is the only aerospace standard lightning current component relevant to the generation of out-gassing phenomena in Zone 2A. Lightning direct effects tests where the C-component was used in isolation did not produce any out-gassing when there was a total deposited charge of both 100 and 200 Coulombs. Combined waveform sequences of D, DB and DBC all produced similar results; and it was found that out-gassing is sensitive to scaled versions of the D-component.