Numerical Analysis of Lightning Induced Transients in Electro-Electronic Systems Interfacing an Externally Mounted Sensor

This paper describes a computer analysis developed to
evaluate the expected lightning induced transients in a critical
aircraft equipment interfacing an externally mounted sensor
subject to a direct lightning attachment. At first, a discussion
of the coupling mechanism in a metal airframe is presented.
Once it is established an understanding of the coupling
process, by modeling and testing a metal airframe, the article
progresses to the evaluation of a case where the skin material
is replaced by a quasi-isotropic carbon fiber composite
laminate. Finally, it was also investigated the effects of the
inclusion of a metal strip, to divert the current from the
cabling, and the addition of cable raceways in the composite
mounted installation. The results found for lightning induced
transients, in each different proposed installation, provided
valuable comparative effects expected for each airframe
construction design and an indication of the level of protection
to be considered for each respective system application.