Re: Aircraft and lightning

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Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

> Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

>
> The one I observed was essentially silent (or, at least, you couldn't
> hear it over the relatively high background noise in the plane).
> There was a lot of turbulence at the time, so there was a lot of
> rattling and creaking noises, as well as a higher than usual amount
> of engine noise (no fool, that pilot.. carry lots of power, so you
> don't have to wait for the engines to spool up when you need it) It
> was VERY bright, but, inasmuch as there was lots of lighting in the
> area, most people had their window shades down and were trying to
> watch the movie.  (Aside from the inevitable folks going "we're going
> to die" from the turbulence.)

With the plane moving at say 560mph and the velocity of sound at 680mph (sea
level lower at altitude), perhaps that stops or reduces the sound amplitude
reaching the cabin. and distorts the
steep front in to a more gentle rise that would be less detectable with the
cabin background noise.

> As far as the sound of lightning "up close and personal" goes, the
> three times I've been near a stroke, it's sounded more like a very
> loud crack rather than a boom.  More precisely, it sounds like "hiss,
> buzz, crackle, BANG" as the field comes up before hand.

Many of the near (not close, noticeable delay between flash and bang but
less than second ) strikes I have observed are preceded by more of tearing
ripping type of sound followed by a bang.
A boom type of sound a associate with strikes several seconds away.
I had assumed the tearing ripping  type of sound was the sound of the
leader. But this is a guess.
For close (flash and bang almost simulation, fraction of a second) strikes I
have only heard the bang.

> what the buzz comes from, but it's been there all three times, and
> it's very distinct from the usual corona hiss and crackle we're all
> familiar with.  Someone suggested that it's some sort of relaxation
> oscillation as a metal object in the field charges up and discharges
> with a streamer.  The whole time sequence is maybe 3 or 4 seconds.
> Except for the hiss and buzz, which can last a lot longer, and occur
> whenever the field is high, even without a long stroke, and is really
> really creepy, because you just know something big might happen.  You
> also get to feel your hair standing on end.
>

The only time I felt my hair move on my head was when  sheet of lightning
moved over my me.
It was one of those tendril like sheets sometimes observed to progress
outwards from an initial discharge.
I assumed it was my hair relaxing as the field disappeared. I had recently
had my hair cut relatively short perhaps 1/2inch.

I have never heard a buss or hiss. If I had I would be inclined to run for
cover or crouch on the ground.

I have observed such tendril sheets move from horizon to horizon from a
storm several miles away.
Its even possible to follow them with movements of your head.
The one that I assumed made my hair move, progressed  almost instantly
across the sky and with no sound.
It appeared to be at a relatively low altitude compared the sheets I can
follow with my head.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400