Since the lightning electric parameters are quite scattered we concentrate on some current waveforms prescribed by the aeronautical standards. Moreover we concentrate on the highest power phase of the discharge which is also called the phase-A. In this phase a maximum current of two-hundred-thousand of Amperes is reached. The loads generated by the various test settings are investigated using a dedicated numerical CFD code. A comprehensive reacting thermodynamic model is considered along with a time-splitting technique particularly suited when a high-temperature gas forms.The validation of our code is particularly tricky since it is not possible to measure the pressure field directly on the impulsed panel. In fact the high current associated with the phase-A can easily disturb or even damage a pressure gauge. To overcome this, we have moved the pressure gauge to safer positions connecting them to the panel with some tubes. We have developed an innovative multi-scale technique that simulates both the air in front of the impulsed panel and the tubes. Through this we get a direct comparison between the numerical results and the experimental ones. Moreover we have acquired some images in optical wavelengths to get a time-dependent measure of the arc channel. The optical data are complemented by a total light-intensity measure. Once validated, our code has been used to investigate the various current waveforms prescribed by the aeronautical norms. Both the damped oscillating waveform and the unipolar impulse are considered. Moreover we have also estimated the effects of other features such as the jet diverting or the triggering wire. Our main contribution is to give a more precise picture of the mechanical interaction between the arc and a metallic plate. Some of the methodologies developed in this work can be applied with some modifications to composite parts.