Shocking Truth About Lightning Strikes

Back in the day, when Uncle Sam footed the bill for my flying addiction, the rules and regulations required that we steer clear of thunderstorms by 10-20 miles. 

In theory, this would help us avoid errant lightning strikes, hail, and any other side effects of these 50,000-foot-tall natural hazards to navigation. 

So, imagine my surprise when last  week I read that in 2017 NASA identified a 515-mile-long lightning strike  that stretched from east Texas to  Kansas City, Missouri. Not sure how you avoid that one.  

Actually, in the airline world, lightning strikes occur much more often  than you might think. 

Statistically, every airliner gets struck by lightning about once a year. Thankfully, these strikes usually cause little damage, and in most cases after checking to see if all the systems are on line, the plane continues to its destination. There it is inspected, and the passengers and crew have a good story to tell. 

This kind of outcome is due to the rigorous certification standards for air carrier aircraft, both the aluminum and composite variety. However, down here in General Aviation Land, the story is both good news and bad news.  

The good news is that general aviation (GA) lightning strikes are rare,  and fatal accidents associated with strikes are even rarer. This may be due to the “little airplane vs. big storm” theory that causes us piston pilots to steer clear of these behemoths. 

But as our little airplanes become more capable, especially in the area of near real-time graphic weather data, it may tempt some to try to boldly go near severe weather when they shouldn’t. 

And the bad news is that our fleet of piston singles and twins contain a mixed bag of lightning protection. Older aircraft operating under type certificates from the 1960s and ’70s, which make up a large segment of the fleet, are generally less protected than more recent designs. 

And let’s face it. A lightning strike on our tiny 2,500-pound chariots is going to be a bit more up close and  personal than on a half-a-million- pound airliner. So, let’s dig in and  see if there are a few things we might need to know. 

Lightning: Where to Find It 

Down here in Florida where I live, we can set our watches by the afternoon thunderstorms. 

During the day, the clouds build up over the center of the peninsula, and around 4 p.m. EDT, they head toward  the beaches, spewing heavy rain, deafening thunder, and some truly awe  inspiring cloud-to-ground lightning. An hour later, the skies are clear. 

This daily process is the recipe for the creation of lightning. Warning: I, a pilot, am about to attempt a scientific  description of the lightning generation process, so all you amateur and  professional meteorologists out there cut me a little slack. 

Lightning strikes in and around thunderstorms occur due to the vertical development of the storm. Within the clouds rising and descending ice crystals, soft hail and precipitation cause the middle to top  of the storm to take on a positive electrical charge. At the same time, the  lower reaches of the storm generate a negative charge. 

Anyone who has connected the positive and negative battery posts with jumper cables on their car will see where this is going. Oh, and all of this positive and negative charging can be going on well before precipitation is actually coming out the bottom of the storm. 

Temperature plays a role as well. Most lighting strikes occur between 5,000 and 15,000 feet, or within 10,000 feet at or above the freezing level. As the storm is developing, with heavy rain reaching the ground, the lightning can take on three forms—intra-cloud, or lightning within the thunderstorm itself, cloud to ground, or cloud to cloud. 

To these technical descriptions I like to add my own personal favorite: “cloud to my little airplane.” This last one I like to avoid. 

What Does a Lightning Strike Look Like? 

I have been struck by lightning/static discharge three times during my flying career—thankfully, never in our beloved Cessna Cardinal. 

Two of the strikes occurred on a single flight at 12,000 feet over the stunning vistas of Monument Valley in southern Utah. 

We were entering a low-level navigation route in the mighty B-52 Stratofortress and entered an innocent-looking cloud. There was a little virga, or rain that does not reach the ground, coming out of the bottom, and because our radar was configured for our descent to 800 feet above the desert, we did not have a clue what was coming. Shortly after entering the cloud, the precipitation and turbulence began, and the radios began to snap, crackle, and pop—but not in a good way.  

Then suddenly, five fingers of electrical energy reached down over the nose and left side of the “BUFF,” about 2 feet from my left hip. The thunder-clap was deafening, even through our  helmets and earmuffs. Seeing that we were still alive, and all the major systems appeared to be working, we started a climb and turned toward home in California. Too late, as the radio began to hiss and pop again, and another strike occurred.  

Once safely back on terra firma, we tallied up the damage. There was a silver-dollar-size hole in the nose radome, and several burn marks on the side of the cockpit area. But that was not all. The wingtips of the bomber are made of a composite material called phenolic resin, and apparently the charge passed through the fuselage, through the wing fuel tanks with around 80,000 pounds of JP-4, and as it exited both wingtips, blew the wingtip trailing edges apart. However, because the B-52 had  been hardened against electromagnetic pulse, and the systems were  stout analog computers, we never noticed any damage until after landing. 

Dry Thunderstorms and Virga 

One lesson learned from this close encounter of the lightning kind was that strikes can occur in a variety of conditions. 

Years later while living in northern Arizona, I learned about these “dry thunderstorms” that caused so much damage years earlier. Unlike East Coast storms, the spring and summer monsoons in the Southwest cause thunderstorms with high bases, upward of 10,000 feet msl or more, that spew wispy veils of virga and elegant lightning bolts that reach down 5,000 feet or more to the ground. 

These are one of the chief causes of the damaging brush fires that plague the region, but they can also be deadly to the unwary pilot who believes the virga is safe to fly through. 

Who Is St. Elmo? 

Another indication that you are getting too close to a storm’s electrical activity is the blue glow, plasma  plumes, or miniature lightning bolts that play across the cockpit windows and leading edges. 

St. Elmo’s Fire, not to be confused with the 1980’s coming-of-age movie,  is the result of atmospheric ionization, similar to what happens inside a  neon light, coming into contact with your airplane. Sailors have seen it for centuries on the tips of their masts in bad weather. Its name is derived from St. Erasmus,  the patron saint of Mediterranean sailors. It is also a good sign that you are nearing an area of unstable air and electrical activity, so it might be a good time to change course. 

Then There Is Thundersnow 

While we normally equate lighting  with spring and summer thunderstorms, there are some occasional  oddities that can catch us napping. 

Years ago, I was spending a delightful evening as the supervisor of flying, armed with a pickup truck and a radio and driving around the ramp at Griffiss Air Force Base in Rome, New York. My job was to keep an eye on the weather and help the flyers get off and back on the ground safely. 

The usual lake-effect snow was  falling briskly, and the wind was whipping, unusual for this upstate winter wonderland of quiet snowfalls. Of course, the freezing level was right at the surface.

Suddenly, the sky lit up, the thunder was instantaneous, and I nearly jumped out of the truck. This was my first, but not last, encounter with thundersnow. While rare, it reminds us that the electrical energy in the clouds, especially at the freezing level and above, can be present at any time. 

Rules Are the Same Everywhere 

It does not really matter where you fly, some good rules of thumb to avoid lightning strikes apply. 

Avoid active thunderstorms up to 20 miles. Resist the temptation to  use your NEXRAD display to navigate between cells. That cloud-to-cloud, or cloud-to-your-little-plane  lightning bolt is just waiting for you to try it. 

Remember that the airspace at and above the freezing level is the most likely lightning generator. If you live in Florida like I do, don’t try to fly under the ominous dark clouds in the afternoon just because the rain has not started to fall. Avoid the rain shafts by a wide margin. 

If you fly in the Northeast, the embedded storms can be the hardest to anticipate. My guideline is, if I am not in clear air on top, navigation through an area of storms is a no-go and it is time to land.  

Avoid First Lightning Bolt—and All the Rest 

NASA astronaut Frank Borman famously said: “A superior pilot uses his superior judgment to avoid situations which require the use of his superior skill.” 

This applies to thunderstorms and lighting avoidance in spades. Today we have near real-time graphical weather tools on our iPads that let  us see where precipitation, lightning strikes, and turbulence exist. We know the temperature at altitude within a degree or so at all times. 

More than that, we keep our “mark one eyeballs” out of the windows to help us avoid electrical storms and our own good judgment to keep us safe. Let’s use all these to avoid that first bolt of lightning, and all the rest. 

Fly safe!