ABSTRACT
The NASA F-106 has acquired considerable data on the rates-of-change of electromagnetic parameters on the aircraft surface during over 700 direct lightning strikes while penetrating thunderstorms at altitudes ranging from 15,000 to 40,000 feet. These in-situ measurements have provided the basis for the first statistical quantification of the lightning electromagnetic threat to aircraft appropriate for determining lightning indirect effects on aircraft. The data are presently being used in updating previous lightning criteria and standards developed over the years from ground-based measurements. The new lightning standards will be the first which reflect actual aircraft responses measured at flight altitudes. Nonparametric maximum likelihood estimates of the distribution of the peak electromagnetic rates of change for consideration in the new standards are obtained based on peak recorder data for flights which have multiple strikes. The linear and nonlinear modeling techniques developed provide a means to interpret and understand the direct strike electromagnetic data acquired on the F-106. The reasonable results obtained with the models, compared to measured responses, help yield confidence that the models may be credibly applied to other aircraft types and used in the prediction of internal coupling effects in the design of lightning protection for new aircraft.
