Hi All

Lots of interesting questions on lightning.  I can tell you that on boats, what will typically happen is that the attachments on the shrouds, backstays, etc will be burned out and the rig typically will come down.  For those that ground the through hulls (which would typically be bronze), the through hulls may be burned out and the boat may sink, or it may burn out the ground wire instead.  In other words, the non-conductive parts are blown out.  But lightning is a weird phenomenon and no two strikes are exactly the same.

One day I was out racing when another boat was hit by lightning.  The lightning  generally traveled down the backstay but made a bit of a detour and traveled through a crew members's arm.  It turned black and I never heard the final outcome but he was alive when he went off to the hospital.  And on that, the boat never sank nor did the mast come down.  But the rig was not grounded anywhere.

And as it was pointed out earlier, metal planes generally fare pretty well with strikes and most pilots flying the heavy iron never even know they were hit.  However that is not always true.  I know one of the checks that is routinely performed on planes I've worked on is continuity checks to see what rivets got zapped as the lightning was leaving the plane thus oxidizing them and making them electrically isolated from the rest of the plane.  These are simply drilled out, reamed a bit and re-riveted.

Anyway, Beechcraft did a lot of work on lightning strikes for their Starship.  The damage was always pretty minimal as I remember it but my old boss Andy Marshall I think has specific knowledge.  I'll check.  A lot of you may have his book "Composite Basics" which is sold through the LML bookstore and Aircraft Spruce.  I don't remember anything on lightning strikes but I'll ask him what he knows about it.  Also I'd expect very different results between a carbon laminate and an all glass plane.  I'll see what he has to say about that.

If you're going to OSH this year, you also might want to talk to him about it after one of his lectures on composites.

Dan Newland