Re: getting hit by lightning

From:         falke@pweh.com ( 0 Falke_Charlie phone dist )
Date:         17 Jul 96 04:05:34 
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Konrad Kelley <wingnut@mail.utexas.edu> writes:
> In article <airliners.1996.1228@ohare.Chicago.COM> Pete Mellor,
> pm@csr.city.ac.uk writes:
> >That was always my understanding. However, I have heard that the
> >increasing use of composites in airframe construction has significantly
> >reduced the "Faraday cage" properties of modern airliners. Anyone know
> >anything about this?

>         The addition of a fine wire mesh in the composites provides
> the current path for lightning protection and greatly reduces the
> damage to the composite. So the Faraday cage is still there. A recent
> "Beyond 2000" or "Next Step" had a segment on this issue.

   I covered the FADECS on board the A310-300 cert flight test with
PW4152s.  During one flight, we had a direct strike to the right
engine.  (We were struck 4 times that I could hear, it made a very
curious sound, not like I expected, more like snapping wood.)
   There was a slight discoloration on the composite fan case
where it was hit, and some missing aluminum (~3/8") where (I presume)
the stoke left via the fan nozzle.  The FADEC, just behind the
composite, didn't complain.  (The harnessing, of course, is well
shielded.)

Charlie Falke
System Test Team Leader         Pratt & Whitney Aircraft
203-565-9063 desk 1261 fax      m.s. 121-05
203-565-6462 x286a stand        400 Main St.
203-565-1261 Fax, PW office,    East Hartford, Ct 06108