Lightning on aircraft
Does lightning strike an aeroplane in flight?
If not, what is the reason?
Sujitha, Chennai
Nothing prevents lightning from striking an aircraft during flight. It is the metallic or conducting surface that protects the aircraft. When a lightning strikes the aircraft, the large electric discharge current gets thinly spread over the conducting surface of the aircraft and gets out from some other part of the surface of the aircraft. The physics behind this shielding as well as electromagnetic shielding is called Faraday Cage Effect.
Fuel tanks are vulnerable and will explode if there are electrical discharges inside the tank. Further, the fast flowing current through the surface will induces currents in the electrical circuits of aircraft and play havoc. Fortunately, fuel tanks, electrical circuits and passengers inside are well shielded from lightning current by a suitable design of conducting surfaces of the aircraft.
Contrails or vapour trails are line-shaped clouds produced by aircraft engine exhaust, at high altitudes. They are composed primarily of water, in the form of ice crystals. Contrails have also been observed to influence lightning to a small degree. The water-vapour-dense contrails of aeroplanes may provide a lower-resistance pathway through the atmosphere having some influence upon the establishment of an ionic pathway for a lightning flash to follow
Prof. G Baskaran, Institute of Mathematical Sciences, Chennai
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