Are airplanes lightning proof?

This is what I remember from my first flight ride: I had pressed the ‘Help’ button so many times while my mom was asleep beside me that the air-hostess came and disconnected it. Those days, the button came in what looked like a telephone that was connected with a cord to the seat and was not integrated to the dashboard on top of your head. Even though I was just two, I knew that what I had done was cause enough to be embarrassed and have always chosen the window seat ever since to occupy my mind with the beauty of the skies.

Over the years, many like me would have lost track of the number of times they have walked the narrow aisle. Over the years, we have also lost track of how we could, once-upon-a-time, walk into the airport and literally see the flight standing 20metres away and board it like we were climbing into a taxi.

Many things have changed. Things have changed so much that while Air India once gave cotton to everybody for their ears, those with the need need to place a request for the same nowadays.

We are flying into a new city at 6am, finishing the meeting and catching the evening flight back home as if it were a bus. Why, turbulence feels just like driving on a potholed road! Surya namaskars are done as the first rays of the rising sun kiss our cheeks through the windows. The night lights of the bejeweled city below mesmerize us for a candlelight dinner with the stars above as we land after a hectic day. The magic of nature enthralls each of us as we see a million hues on the horizon or the snowy white of the clouds which puts Tide ki safedi to shame.

                 

The other day I was on one such flight, eating and conversing with the moon while soaring in the darkness and.. a sudden flash of brilliance startled me as it sliced the sky in two. A second later, it was as if nothing had happened at all. The darkness and the silence of the night was restored. The monotony of the engine’s drone continued.

And that is when I got curious: How are airplanes lightning proof?

The last airline crash in the USA blamed on lightning was more than 40 years ago, though every flight gets hit atleast once a year on average, I am told. During a 1980s 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 could induce relatively small electrical currents that could damage electronic systems.

As Edward J. Rupke (senior engineer at Lightning Technologies, Inc.) explains, “Initially, the lightning will attach to an extremity such as the nose or wing tip. The airplane then flies through the lightning flash, which reattaches itself to the fuselage at other locations while the airplane is in the electric "circuit" between the cloud regions of opposite polarity.”

Most of the planes are made of aluminum bodies, a very good conductor. Modern aircrafts might be made of advanced composite materials which are significantly less conductive than aluminum itself. A lightning bolt's electricity flows along the airplane's skin and into the air as long as there are no gaps on the exterior. Every circuit and equipment is checked for lightning safety according to the federal laws. The pilots may be blinded for a few seconds. However, there is no report of this having caused any major issues.

A point to note: When flying through a heavily charged region of a cloud, airplanes might actually TRIGGER lightning bolts that originate and then extend in opposite directions away from the plane!

                           

The major concern would be the fuel system, where even a tiny spark can prove to be disastrous. The aircraft skin around the fuel tanks is made thick enough to withstand a burn through. Access doors, fuel filler caps, the engines, fasteners and joints – they are all designed to withstand lightning. In addition, new fuels that produce less explosive vapors are now widely used.

The nose cone contains radar and other flight instruments. Lightning protection engineers pay special attention to this area as well. Lightning diverter strips applied along the outer surface protect this area. These strips can consist of solid metal bars or a series of closely spaced buttons of conductive material affixed to a plastic strip that is bonded adhesively to the cone. Diverter strips function like a lightning rod on a building.

So, as long as you aren’t flying in a private jet that is not required to satisfy the safety regulations, you are safe.