Airplane often trigger lightning when flying through a heavily charged region of a cloud.
When a plane is struck by lightning, passengers and crew may see a flash and hear a loud noise.Other than that, there are no serious damage that may occur. That is because of the carefullightning protection engineered into the airplane and its sensitive components.Most airplane skins consist primarily of aluminum, which conducts electricity very well. Bymaking sure that no gaps exist in this conductive path, the lightning current will remain on theexterior of the airplane.
Some more advanced airplanes are made up of composite materials thatcontain an embedded layer of conductive fibers or screens designed to carry lightning currents.Initially, the lightning will attach to an extremity such as the nose or wing tip. The airplane thenflies through the lightning flash, which reattaches itself to the fuselage at other locations while theairplane is in the electric “circuit” between the cloud regions of opposite polarity. The current willtravel through the conductive exterior skin and structures of the aircraft and exit off some otherextremity, such as the tail.This protection is based on the principle known as the Faraday cage, first devised by thephysicist Michael Faraday in 1836. A Faraday cage is a hollow enclosure made of conductingmaterial, such as the hull of an airplane.
In the presence of a strong electric field, any electriccharge will be forced to redistribute itself on the outside enclosure, but the space inside the cageremains uncharged. Thus, the metal hull of the aircraft acts as a Faraday cage, protecting theoccupants from lightning.When a lightning hits a car, lightning flows around the outside of a car, and the majority of thecurrent flows from the car’s metal cage into the ground below. This applies only to those carswhich are made of a mesh metal or other conducting material, which allows the electrical currentto pass through the conducting material without reaching whatever is inside. It moves the currentaround the car rather than through it. In essence, a car acts like a Faraday cage.
However, notall vehicles are created equal anymore. Convertibles do not have metal roofs, which compromisesthe Faraday cage affect. In addition, some vehicles are manufactured out of non-metal parts,which impedes electricity’s ability to flow through the car.Both incidents applies the same principle. In that both acts as a Faraday cage. A Faradaycage operates because an external electrical field causes the electric charges within the cage’sconducting material to be distributed such that they cancel the field’s effect in the cage’s interior.Electrostatics theory also tells us that there is no electric field inside a charged shell. Since itis the electric field which causes the motion of charged particles, there can be no current insidethe shell either.
The current is only experienced as you pass through the shell. This is why,although the airplane and the car is very highly charged, the passengers are in no danger of beingelectrocuted unless they touch the outer surface.
