How dangerous is a lightning strike?

JetBlueA jetBlue flight departs Los Angeles International Airport on January 31, 2019, when a lightning strike occurs. The captain decides to turn around to make an emergency landing. As the fuel tanks are fully loaded it is going to be an overweight landing. Less than an hour after takeoff the plane is back on the ground.

Another emergency landing

The same morning, a lightning also strikes a Southwest Airlines flight departing the same airport. This aircraft makes an emergency landing as well, although in nearby Oakland.

LiightningOn average, a commercial aircraft is struck once every 1,000 flight hours, or 1-2 times per year. However, there is no reason to worry about it.

No crashes anymore due to strikes

Since the late1960s there has been no case of a strike causing an airliner to crash. Thanks to better protection measures this is now a thing of the past. Actually, in most cases passengers will not notice a lightning strike. Even the pilot is often not aware that the plane has been struck.

Aircraft hit by lightning while in the air undergo inspection after landing. In most cases the aircraft is either unharmed or sustains only minor damage.

Faraday cage

LightningActually, the lightning does not strike, but the current goes through the plane. When it happens to your plane you will be safe because the plane frame's metal works like a Faraday cage. Theoretically, the electric charge will keep within the frame and cannot penetrate to the electronics and passengers inside. In reality, however, some of the charge will penetrate into the frame. Therefore, the electronics and engines are protected and secured.

Initially, the lightning will attach to an extremity such as the nose or wing tip. The current will travel through the conductive exterior skin and structures of the aircraft and exit off some other extremity, such as the tail.

Low resistance material

ExtremetiesThis requires material with low resistance, like aluminum. However, new aircraft are increasingly made of lighter composites - like carbon fiber - to safe on fuel. As those materials have a higher resistance copper strips are attached to the frame's surface. This way plane makers can still comply with safety standards.

Don't fly through thunderstorms

It is self-evident that the best protection is to avoid flying through or near thunderstorms. Airlines will in the planning stage of a flight check the route on thunderstorm activity. If necessary, they will alter the route.

During the flight, however, a storm system may form on the route unexpectedly. In such a case, the pilot must divert to an alternate airport as it is the only option. After all, thunderstorm systems are not always accurately predictable.

Tags: lightning strike, emergency landing, Faraday cage, thunderstorms

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