Some Considerations Concerning the Natural Oscillations Excited by Lightning in Aircraft Electrical Systems

The transients induced in aircraft electrical systems by a lightning strike often have a shock-excited oscillatory component whose frequency and damping are functions of the aircraft and its systems but whose amplitude depends on the shape of the disturbance. The relation between the amplitude of the oscillations and the parameters of the transient excitation (including the slope of the leading edge) is investigated analytically, assuming linearity. The effect of damping (resistance) in the systems is considered. The results are applied to some specific circuits, excited by the lightning current waveforms specified in the test Standards.