 One of the problems of interest
nowadays is the effects of lightning on aircraft. Some of these
effects are melting of the aircraft skin, deformation due to pressure
waves and magnetic forces, explosive vaporization of conductors,
sparks in the fuel system which can cause explosion and damage in
externally mounted composite materials.
Another serious issue is the electric and magnetic fields coupled
to the interior of the aircraft. These can cause interference to
the electronic equipment. This is of increased importance nowadays
for two reasons: One is the high dependence of modern aircraft on
sophisticated electronic circuits to perform flight critical operations.
These circuits operate at low voltage and current levels which makes
them more sensitive to electromagnetic interference. An other reason
is that composite materials are used increasingly in modern aircraft,
since they offer advantages in terms of mechanical strength and
weight. However these materials are poor conductors of electricity
and do not offer as much shielding as the traditional all metal
structures.
In Figure 1 we see the
surface current density on the Blackhawk helicopter, where a lightning
current enters at the end of the front right rotor and exits from
the right wheel.
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