Static Discharges?

Mon Jul 03, 2000 5:47 pm

I was aboard a Kiwi B727 going from ORD to LGA in the summer of about 1996 and as we were climbing there was a very loud "bang". Of course this startled many of the passengers including myself, but I didn't notice any change in engine thrust, so I figured it wasn't anything major. The captain came on the PA and assured us that it was nothing to worry about and that he'd explain what had happened when we reached our cruising altitude, at which time he explained that we had experienced a "static discharge".

1) Is a static discharge similar to a lightning strike?
2) How common are they?
3) If they're uncommon, has anyone else on this forum experienced one?


RE: Static Discharges?

Wed Jul 05, 2000 12:49 pm

Static discharges can and do occur while flying in precipitation. It's alot like shuffling your feet across the carpet and touching an object and seeing an electrical discharge. The friction of a fast moving aircraft through the precip creates the same thing.

Dry precip, such as snow, can create some pretty spectacular "St Elmo's fire"(static electricity). You'll see electrical discharges across the front windscreen that look like little blue lightening bolts arcing all over the window. On propeller driven planes, you'll see a blue fluorescent ring around the arc of the blades. You can also see blue flames of electrical discharges off of pitot tubes and static wicks on the wings. This is all harmless but can look spectacular and alittle unnerving for the first time viewer.

Occasionally, the build up of static electricity in precip can be so great as to create it's own lightening bolt of discharge departing the aircraft. This is probably what happen on your trip. While alarming to the passengers, it's usually harmless in modern jets.

RE: Static Discharges?

Wed Jul 05, 2000 2:28 pm

Thanks for the response HeavyJet. I kind of figured it was akin to the static discharge one experiences with carpeting and also similar to St.Elmo's Fire, but wasn't sure. It was odd though, because most of my commercial pilot friends had heard of it, but not personally experienced it.


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