How are planes protected from lightning?

Lightning strikes most of the time as they pass through a cloud as planes often climb or descend. Lightning can also be triggered when airplanes pass through electrically charged areas.

A lightning strike plane becomes part of the charge transfer line between zones that are electrically opposite charged, for example, the cloud and the ground, or the cloud and another cloud. Lightning first touches the pointed parts of the aircraft, such as the nose or wing tip. Around the point where lightning touches the plane, a glare can be seen due to the ionization of the molecules in the air. Electrically charged particles moving along the lightning line then travel along the conductive outer surface of the plane and come out of another pointed part of the plane, for example from the tail.

Airplanes are usually made of aluminum, which has a high electrical conductivity. Today, composite materials consisting of a combination of materials of different properties can be used in the fuselage of aircraft. The conductivity of these materials is generally lower than that of aluminum. The parts made of composite materials are therefore coated with highly conductive materials to smoothly transfer electrically charged particles along the outer surface of the aircraft in the event of lightning strikes.

Sparks that occur at the points where lightning strikes the plane can cause melting or burning. The damage caused by lightning strikes on the fuselage of aircraft is generally not deeper than 1 mm. The outer coverings of the aircraft are made of materials that are thick enough to prevent them from being damaged by such effects, mostly metal. Lightning strikes can cause parts with low electrical conductivity to deform and rupture.