What Happens When Lightning Strikes a Plane?
Quora.com is a question-and-answer site where content is written and edited by its community of users. Occasionally we syndicate content from the site if we think it will interest TPG readers. This article originally appeared on Quora.com in response to the question, What Happens If Lightning Strikes a Plane? and was written by Sky Rudolph, an aeronautical engineer working in aircraft testing and certification.
The short answer is that lightning usually strikes the aircraft on the nose, then travels along the skin until exiting the aircraft at one of the extremities. While it is true that aircraft continue to function safely after a lightning strike (as design rules require) and that there's nothing that should concern a passenger, it does have an effect. Because of this, a lightning strike inspection will be required upon landing.
This inspection will check for any structural damage caused by the strike. The inspection will usually consist of locating the point of entry (usually the nose) and following the electrical path along the skin. It is common to find scorched rivets where the small gap between the edge of the rivet head and adjacent skin results in arcing as the electricity jumps the gap.
The exit point is also identified, often the tail, wing tips or a corner of a control surface. If the electricity makes its way onto a control surface, there will often be some damage to the bushings/bearings, requiring their replacement. There is often some damage at the exit point which requires some repair. There are relatively rare instances of effects to various electrical or sensor systems on the aircraft, but it certainly can happen.
In the course of my aircraft testing career, I have been on aircraft struck by lightning four times. Every time has resulted in some level of damage that needed repair (although the smaller stuff could be safely deferred if needed, if an aircraft is in commercial service).
A google image search for "aircraft lightning strike damage" will show you some of the more extreme cases — these are not for the faint of heart, or for those with a fear of flying to view, however. Although some of those pictures look dramatic, it should be stressed that the aircraft continue to operate safely (if not 100% normally) after a lightning strike.