When flying, you might see a flash across the plane’s window and hear a loud bang, but most likely you won’t even realize a lightning strike has occurred. This is because airplanes are designed with your safety in mind. They act as giant Faraday cages, protecting you from the harmful effects of lightning strikes. Lightning struck do not affect the plane continue to fly safely as it is equipped with lightning protection systems.
What is a Faraday cage?
A Faraday cage is a metal enclosure made of materials such as copper, aluminum, or iron. When an electric field is near the Faraday cage, the electric charge in the metal redistributes itself on the surface. Exposure to an electric field causes an immediate redistribution of the freely moving electrons, inducing an electric field that opposes the incoming electric field, ultimately canceling out both external and internal electric fields. This ensures that anything inside the metal enclosure is not influenced by the incoming electric field.
How does plane act as a Faraday cage when struck by lightning?
The outer shell of a plane is typically made of aluminum, which is an excellent conductor of electricity, effectively forming a large metal enclosure. When lightning approaches the plane, it generates a strong electric field around the aircraft. This electric field induces a corresponding strong current on the surface of the plane. However, due to the conductive nature of the aluminum shell, the current primarily flows along the surface and does not penetrate into the interior of the aircraft. This phenomenon is known as the Faraday cage effect. Consequently, minimal to no electrical field penetrates inside the passenger cabin. This insulation ensures the safety of passengers and electronic equipment inside the plane, protecting them from electric shock and damage.
Conclusion
While passengers are safe from the direct current of a lightning strike, indirect effects like voltage spikes can still occur, potentially damaging sensitive electronic equipment. Planes are always thoroughly inspected after a strike to ensure everything is functioning properly.