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Old 12-16-2002, 04:56 PM
Gaudere Gaudere is offline
Join Date: Jul 1999
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What happens to a helicopter when lightning strikes it?

Does it crash? Are the people inside fried? What about when lightning hits an airplane? How common is being struck by lightning if you are high in the air during a storm in a large metal object?
Old 12-16-2002, 05:10 PM
Richard Pearse Richard Pearse is offline
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We were struck by lightening recently (in a fixed wing aircraft). By that experience I can say that some of the electrics get temporarily fried, turning them off and then back on fixed the problem; and you get lots of little scorch marks over the aircraft. Other than that, no big deal. It is not very common to get struck by lightening, mainly because flying through thunderstorms is best avoided due the extremely turbulent conditions inside them, and hail and icing etc.
Old 12-16-2002, 05:14 PM
Richard Pearse Richard Pearse is offline
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Lightning even.

YMMV of course, some cases may be a lot worse than ours. There's no reason for people to be fried though.
Old 12-16-2002, 05:19 PM
sailor sailor is offline
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Location: Washington dc
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My boat was hit by lightning and no electronics survived. Not even things which were not connected to anything. Everything fried. I am glad I was not onboard at the time.
Old 12-16-2002, 06:21 PM
Broomstick Broomstick is offline
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I wouldn't say aicraft (of any sort) get hit by lightening is common, but it does happen. Things like passenger jets undergo extensive testing that not only includes (dead) chickens lobbed at the windshield by cannon but also testing of resistance to damage from lightning.

Small airplanes intended to fly extensively in "instrument meterological conditions" also undergo some similar tests, although not as extensive.

(Instrumentation to help detect lightning dangers at a distance and avoid it is also available to pilots, although not all small planes have this installed.)

In general, while the electrics may suffer, the occupants generally survive unscathed, although perhaps shook up from the flash of light, possible accompanying >BANG!<, and blinking/failing instrument panels lights and such. Or maybe it won't affect the electricals at all.

The BIG electrical danger in aircraft comes form the possibility of a difference in static charges between the aircraft and the fuel truck leading to a spark around gas fumes. Which is why, when refueling, a grounding wire is strung between the truck and the aircraft, to even out any differences in charge.
Old 12-16-2002, 06:27 PM
happyheathen happyheathen is offline
Join Date: Nov 2001
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All of the above are assuming the aircraft is metallic, or otherwise conductive (being on a wooden/fiberglass boat during a lightning strike is not advised).

In the case of a composite plane (without the new, rare, expanded metal groundplane), the answer I got when I asked about the result of a strike was "You're toast". This was the guy selling the kit.
Old 12-16-2002, 06:31 PM
kanicbird kanicbird is offline
Join Date: May 1999
Posts: 18,608
sorry to hear that sailor. The difference is that your boat provides a path directly to ground (I assume salt water) so had a great potential difference. An aircraft offers no such difference in potentail and results in (usually) little dammage.

Glad you survived it.
Old 12-16-2002, 09:00 PM
bbeaty bbeaty is offline
Join Date: Aug 1999
Location: Seattle WA USA
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When lightning hits aircraft, it doesn't "strike" the aircraft, instead it starts out on the aircraft and leaps outwards.

You'd think that a lightning bolt would have a hard time finding a tiny plane in those cubic miles of atmosphere. But since the airplane strikes the thunderstorm instead of vice versa, lightning on planes is much more common than you'd think.

Analogy: Stress a piece of glass by stretching it, but not so hard that it breaks. If you press the tip of a nail into the stressed sheet of glass, cracks will start at the nail tip and race outwards. The glass is like the space around a charged thunderstorm, the stresses in the glass are like the intense voltage-field in the air, and the airplane supplies the "defect" which concentrates the forces in one spot and starts the "cracks."

Once a crack has started in glass, the concentrated stresses at the tip of the crack will keep it getting longer. And once a lightning bolt has started in the e-field near a charged cloud, the concentrated e-field at the tip of the bolt keep it going.
Old 12-16-2002, 09:17 PM
Race Bannon Race Bannon is offline
Join Date: Oct 2000
Location: Huntsville, AL
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I'm no electricity expert, but I do know that in military helicopters, care is taken to design for lightning strikes. Composite materials (especially blades) are designed to be conductive, even if material is added just for that purpose. Bonding straps are provided between components. Testing is even conducted on things like blades and such to see if there are any problems.
Old 12-16-2002, 11:27 PM
Bob55 Bob55 is offline
Join Date: Sep 2002
Location: Orlando, FL
Posts: 1,179
Ever seen those guys that dangle outside helicoptors to fix huge electrical wires way out in the wilderness? They touch it with a stick first and the electricity goes thru the stick, through the holder, and into the helicoptor, creating an equilibrium state. I'd guess being hit by a lightning bolt in the air is similar. Also, since the electricity has no where to go, there's no reason it would want to hit the helicoptor, lightning bolts like to find charges from the ground to release their energy to.


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