Answers: Does lightning hit airplanes

By Jack Williams, USATODAY.com

Q: My daughter is concerned about airplanes flying during thunderstorms being hit by lightning. From what I have read thus far, I understand that the greatest risks to planes flying in a thunderstorm are turbulence and lightning flashes that temporarily blind the pilots, but I have not read anything regarding lightning actually striking a plane in the air.

Camera inside a NASA F-106B catches a lighting bolt — to the left of the pilot's head — hitting the airplane's tail. NASA

A: Lightning regularly strikes airplanes. In fact, as far as anyone knows, the odds are that each airliner in the USA will be hit by lightning once a year. (Obviously some would be hit more than once, some not at all.)

But, lightning has not caused an airliner crash in the USA or of a U.S. airline plane anywhere in more than 40 years.

Protection begins with the fact that airliners, and the majority of other airplanes, are made of aluminum, which is a very good electrical conductor. A lightning bolt's electricity flows along the airplane's skin and into the air. As you've found out, one danger is that the flash could blind the pilots for a few seconds, but I've never found any accounts of this causing any problems.

Lightning protection goes far beyond airplanes being good conductors of electricity, and the last airline crash in the USA blamed on lightning was more than 40 years ago. On December 8, 1962 lighting hit a Pan American Boeing 707 in a holding pattern over Elkton, Md. The lightning caused a spark that ignited fuel vapor in a tank, causing an explosion that brought the plane down, killing all 81 aboard.

This led to rules requiring that airplanes have built-in systems that ensure that a spark will not ignite fuel or fuel vapors in tanks or fuel lines.

Then, during a 1980s lightning research project, NASA flew an F-106B jet into 1,400 thunderstorms and lightning hit it at least 700 times. The lightning didn't damage the airplane, but the data the jet collected showed that lighting could induce relatively small electrical currents that could damage electronic systems.

This led to regulations that require aircraft electrical and electronic systems, as well as fuel tanks and lines, to have built-in lightning protection.

As you've also found out, thunderstorms offer plenty of other dangers and pilots try to stay away from them, especially strong thunderstorms. (Related: Why pilots try to avoid thunderstorms).

If pilots try to avoid thunderstorms, how come lightning continues to hit airplanes? A few reasons: All thunderstorms, especially small ones can't always be avoided. Lightning often flashes into the air, and to the ground, a few miles from the thunderstorm that generates it. Finally, an airplane or a rocket flying into a cloud that's built up an electric charge can trigger a lightning stroke even though the cloud isn't producing any lightning on its own.

I've searched the National Transportation Safety Board online database and other aircraft accident databases, and haven't come up with any reports of lightning causing any airline crashes in the USA or Europe since the 1981 crash of a small airliner in Germany that killed 21 people. I also found a report of a Chinese-built airliner crashing in China in 2000 after it was hit by lightning, but no details were available, and I have no idea when the Chinese airliner was built or what kind of lightning protection rules were in force when it was built.

All in all, as long as you are traveling on an airplane built in the USA or Europe or a domestic or foreign airline that operates in the USA, I think the only danger you could face from lightning would be if you happen to board or get off the plane at an airport where you walk down steps and across the ramp into the building. I don't think I'd want to do that if a thunderstorm were around. But, I'd hope that the airline I'm flying on would not want to expose its employees, much less the paying customers, to the danger of being hit by lightning.

In fact, just a few days ago, we reported that flights to and from Denver were delayed because the airlines said lightning that was hitting near the airport was dangerous to their employees. If you're ever on a flight that's delayed for a reason like this, you have no reason to complain.

(Related: Resources: Lightning science and safety and Understanding aviation weather).