Why is the front windshield of the cockpit covered with power grids when the plane flies in thunderstorm weather?

The problem of lightning strike has been considered in aircraft design, and there are targeted solutions. For the traditional aluminum alloy structure, because aluminum is a good conductor, lightning strike will not cause serious consequences, generally two holes are pierced in the skin. The development direction of aircraft is to use a large number of composite materials, and the conductivity of composite materials is relatively poor. When lightning strikes, it will generate a lot of heat to burn or even explode, so measures must be taken during manufacturing, such as adding conductive materials. One of the reasons why composite materials are still widely used is the doubt and controversy about the lightning resistance level.

The fire in St. elmo was actually caused by the strong electric field in the thunderstorm that ionized the air in the field when the plane passed through the thunderstorm. Because the very large potential difference in thunderstorm environment exceeds the dielectric breakdown value of air, air becomes conductive and emits strong light in the process of conduction.

For the plane in flight, the whole can be regarded as faraday cage, and it is not afraid of being struck by lightning.

Generally speaking, the cockpit windshield consists of six windows: front windshield, side sliding window and fixed window. In the 1920s, ordinary glass was first used for airplane windshields. Later, with the improvement of aircraft flight speed, composite glass was used; After 1950s, it became a multi-layer composite windshield made of plexiglass or tempered glass. After World War II, airplanes began to fly under pressure. In order to improve the bird impact resistance of windshield and prevent the sudden explosion of aircraft cockpit glass, the United States and the Soviet Union began to study the tensile orientation of plexiglass. The aviation single-layer windshield is gradually developing towards integration, integration and thinness, and more attention is paid to the ergonomics of transparent parts, so as to realize the comprehensive optimization of optical performance, structural strength and special functions and provide a safer, more comfortable and efficient driving environment for pilots?

There is another example in aviation history. The St. elmo fire almost caused an air crash. However, the fire in St. elmo was not caused by thunderstorms, but an accident in which volcanic ash particles rubbed on the plane when the plane crossed the volcanic ash cloud, and the engine swallowed volcanic ash and stopped for four times. Fortunately, it finally restarted in the air.