Sunday, June 1, 2008

lightning is striking again

My plane was hit by lightning on my way back from California. There was a big thud, a lot of light, and the plane jolted. It hadn't really come up as an issue before:


How is a plane protected from Lightning strikes?

Asked by: Sridhar Narayanan


Since the outer skin of most airplanes is primarily aluminum, which is a very good conductor of electricity; the secret to safe lightning hits is to allow the current to flow through the skin from the point of impact to some other point without interruption or diversion to the interior of the aircraft.

Estimates show that each commercial airliner averages one lighting hit per year but the last crash that was attributed to lightning was in 1967 when the fuel tank exploded, causing the plane to crash. Generally, the first contact with lightning is at an extremity...the nose or a wingtip. As the plane continues to fly through the areas of opposite charges, the lightning transits through the aircraft skin and exits through another extremity point, frequently the tail (as shown by Gauss's Law).

Another related problem with lightning is the effect it can have on computers and flight instruments. Shielding and surge suppressors insure that electrical transients do not threaten the on board avionics and the miles of electrical wiring found in modern aircraft. All components that are vital to the safe operation of commercial aircraft must be certified to meet the stringent regulations of the FAA for planes flying into the United States.

Answered by: Rich Uranis, B.S., University of Michigan, Ann Arbor

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