Modern aircraft, particularly passenger jets, have a number of inbuilt or on-board features to protect them from damage due to lightening strikes.
The first and most useful piece of equipment is called the Pilot. The pilot and a weatherman back on the ground will try and plot a course that means the aircraft will not have to fly through any storm clouds on its journey. Should an unexpected storm formation actually be encountered, the pilot will often try to climb over it, preventing damage from downward directed lightening altogether.
Should the aircraft find itself in a storm cloud anyway, or below one, it has other features designed to protect it and its occupants. The skin of most modern aircraft is made of aluminium, due to its excellent strength to weight ratio and relative cheapness and ease of manufacture. Aircraft are generally struck at one end, such as the nose, with the lightening exiting through the other, i.e. the tail (this is shown by Gauss’ Law). The aluminum skin of the aircraft allows the massive current to be safely conducted through the aircraft without endangering passengers or damaging sensitive electronic components such as the radar systems or flight computers.
Aircraft also use small devices called “Static Wicks” to help protect them from lightening strikes. The static wick is a piece of metal, connected to the aircraft’s fuselage by an electrical connection, with one or two needle-like spikes on the end. These act in the same way as lightening conductors, which do not actually conduct the lightening – the sheer current would melt them. Lightening is, as all electricity is, caused by a difference in charge between one point and another. When that difference gets too great, and some air between the points is ionised (has electrons removed from the atoms. This allows the material to conduct electricity), then a lightening bolt is generated, as electrons flow from one point to another to return the difference in charge back to nothing, i.e. 0V (V, Volts, is the measure of the difference of charge between two places). The static wick on the aircraft allows the air and the aircraft to be at the same charge. If the aircraft is positively charged, then the Wick takes electrons from the air (electrons carry a negative charge), and the plane returns to electrical neutral. If the aircraft is negatively charged, the wick conducts excess electrons back to the air, again resulting in electrical neutral. In short, static wicks prevent lightening strikes by allowing the air and the plane to be at the same charge. If the charges are the same, and there is no potential difference (the scientific name for voltage) between the air and aircraft, then it will not be hit by lightening. If for some reason it is though, its aluminum skin will protect it from damage by conducting away the bolt and allowing it to continue to the ground.
