Could your airplane be shot out of the air by lightning strikes?

Illustration for article titled Could your airplane be shot out of the air by lightning strikes?

This picture is undeniably cool, but not what most people want to see from their window as they fly during the holiday season. Lightning is scary for the passengers, but it's no big deal for the plane. There hasn't been a plane downed by lightning for forty years. Here's why.

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I have seen lightning from a plane window. It turned the clouds around the plane into mountains of bright red and green fire, and despite a trooper of a flight attendant insisting that it was only "lights from other planes," no one was fooled. She probably shouldn't have bothered to lie. Though air collisions are extremely rare, other planes are more dangerous to an airplane than lightning is. On average, every commercial plane is struck by lightning once a year.

The three major dangers with lightning are the chance of a spark near the fuel, the temperature of the lightning itself hurting the structure of the plane, and the chance that the charge could move to the interior of the plane and mess with its instruments. A spark igniting the fuel was what caused the last airline disaster due to lightning in 1967. After that, planes were redesigned to keep such sparks and fuel ignition from happening. The temperature is extreme, getting up to 30,000 degrees centigrade but too brief to leave more than a scorch mark on the plane.

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The electrical interference itself is the most fearsome, but is the least likely disaster to happen. Planes form natural Faraday cages. To be fair, Faraday cages are not that hard to make. Benjamin Franklin noticed, when he was first experimenting with electricity, that charge applied to a bucket or cage-like object seemed to distribute itself only on the outside of the object. Michael Faraday studied this more extensively, and started designing cages that we have now. He noticed that if he charged up enclosed metal objects from wire mesh to covered soup tureens, he could leave anything inside - even electrically responsive things like metal balls and wires - and they were unaffected. Objects on the outside of the cage were zapped. The charge ran over the outside of the surface of the Faraday cage, as long as that surface was relatively smooth and unbroken. Planes are made of aluminum, which is an extremely good conductor. Aircraft that aren't made of aluminum often have a thin coating or layer of the conductor in order to let charge flow smoothly over them. They distribute the charge on their outside surfaces, leaving people and equipment undisturbed inside. The lightning then discharges into the air - either heading toward a nearby cloud or the ground. The main danger of lightning now is disorienting the pilots.

Planes do land as soon as possible after being struck by lightning, but that is mainly as precaution. For the most part, in a plane is one of the safest places to be when lightning is around. Still, I'd rather fly through clear skies.

Image: Aindrila Mukhopadhyay

Via The Guardian and Scientific American.

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DISCUSSION

I've actually gotten hit twice by lightening. Well sorta twice, I'll explain the second time in a moment. Both times I was flying the E-2 Hawkeye.

The first time, I got hit it was on the way home to Norfolk, VA at night. It took out all of our DC electrical equipment, which included the radios and the cabin and instrument lights. It got real dark and real quiet all of a sudden. Of course, all the pitot-static instruments such as the altimeter and airspeed indicator still worked. And since it was such a clear night in an area we were familiar with, we didn't have any trouble flying back home. We used our survival radios from our vests to coordinate landing and we used our survival flashlights to illuminate the instruments.

The second time was much more exciting. Think about it afterwards, I don't think we were hit by lightening. Instead I think we charged up going through the cloud and became the source of a discharge.

Anyway, we had just pushed from marshal (holding) on the way back to the carrier on a night landing in the Gulf. So, we were in a 4000 ft/min descent at 250 kts. That's when I noticed that the windscreens looked like the old school "snow" you would get on old TVs and that you could hear a clicking sound. I was sitting copilot and I said to the pilot, "is that rain or hail?" (Hail will really tear up the airplane) He said, "i'm not sure", and we both leaned closer to look. Just then there was a LOUD boom and a bright flash....and then nothing! I could not see at all. The pilot yells, "I can't see!" and I yell back, "me neither". For a bit, I thought the windscreen had imploded and taken out my eyes, so I kept touching my face and making sure it was in one piece.

As you can imagine, screaming towards the ground at night with two blind pilots was not a comfortable position for the 3 NFOs in the back. The problem was, if they got out of their seat to help us fly, they would be disconnected to their parachute. So, they used their altimeter "and seat of the pants" to help us level off and keep wings level.

After a while (it seemed like an hour, but was probably 1 minute) our eyesight came back...slowly (and it was just outlines at first. Like I could see the gauge, but not the numbers or needles). We landed without incident. Of course, we still got the "E-2 dance" and had to land last because the precious Hornets are always low on gas.

The flight doc told me that the optic nerve will actually shut down in the presence of really bright light in order to protect the brain. So we were no kidding blind for those moments.

Crazy huh? Well, those are my two lightening experiences while flying. In both cases the motors still worked and we could land safely. Of course, E-2s are hydro-mechanical. A fly-by-wire jet might have more problems.