Lightning Strikes Gliders

[GM]

Hello all in US-gliderland,
Some time ago, there was an interesting article in Soaring about a
glider being struck by a lightning. I seem to remember a photos of
scourched sneakers, a blown out canopy and other damage. Can anybody
tell me which issue of Soaring this was or if this article is available
online?

Thanks,

Uli Neumann

[Marian Aldenhövel]

Hi,

> Some time ago, there was an interesting article in Soaring about a
> glider being struck by a lightning.

I remember a report on an ASK-21 struck by lightning in the UK. I
have bookmarked

http://www.dft.gov.uk/stellent/groups/dft_avsafety/documents/page/dft_avsafety_500699.hcsp

but that link does not work at the moment.

http://www.pas.rochester.edu/~cline/ASK%20lightning%20strike/ASK%20accident%20report.htm

Seems to have the same report I recall.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"It's easy to make a small fortune in aviation,
provided you start with a big one"

[Chris Reed]

This almost certainly refers to the UK K21 incident in 1999. I don't
know about the Soaring article, but the UK Air Accident Investigation
Board report is at:

http://www.aaib.gov.uk/cms_resources/dft_avsafety_pdf_500699.pdf

Unfortunately the diagrams and pictures which were accessible when the
report first came out are not included in the .pdf.

GM wrote:
> Hello all in US-gliderland,
> Some time ago, there was an interesting article in Soaring about a
> glider being struck by a lightning. I seem to remember a photos of
> scourched sneakers, a blown out canopy and other damage. Can anybody
> tell me which issue of Soaring this was or if this article is available
> online?
>
> Thanks,
>
> Uli Neumann
>

[SAM]

It was in 2002. The author/pilot is Ken Sorenson.
I found it on this on-line index
http://soaring.aerobatics.ws/Soaring_Index/2002/2002_subject.html

[[email protected]]

SAM wrote:
> It was in 2002. The author/pilot is Ken Sorenson.
> I found it on this on-line index
> http://soaring.aerobatics.ws/Soaring_Index/2002/2002_subject.html

In addition, there was a lengthy write up in George Thelen's safety
column in Soaring which is where I recall seeing the scorched sneakers
photo. The pilot was, indeed, Ken Sorenson.

>From the online index, I think it was Oct. 1996 but I'd have to check
my magazine archive at home. The staff at the SSA should be able to
help you.

Chip Bearden
ASW 24 "JB"

[Bob Johnson]

GM wrote:
> Hello all in US-gliderland,
> Some time ago, there was an interesting article in Soaring about a
> glider being struck by a lightning. I seem to remember a photos of
> scourched sneakers, a blown out canopy and other damage. Can anybody
> tell me which issue of Soaring this was or if this article is available
> online?
>
> Thanks,
>
> Uli Neumann

Here's a good writeup, UK in 1999 ----

http://www.aaib.dft.gov.uk/cms_resources/dft_avsafety_pdf_500699.pdf

Bob Johnson

[GM]

Thanks, Brent. That was the one I was looking for. The one about the
British K21 is also very educational.
Thanks to all that resonded.

Uli Neumann

[Bill Daniels]

"GM" > wrote in message
oups.com...
> Hello all in US-gliderland,
> Some time ago, there was an interesting article in Soaring about a
> glider being struck by a lightning. I seem to remember a photos of
> scourched sneakers, a blown out canopy and other damage. Can anybody
> tell me which issue of Soaring this was or if this article is available
> online?
>
> Thanks,
>
> Uli Neumann
>

Did you see some BIG SPARKS lately, Uli?

Bill Daniels

[......... :-\)\)]

A glider is an interesting from the point of view of lightning.

The pilot sits in one of the lightning zone 1 area (i.e. the nose area)
which is prone to direct lightning strike attachment. In more more
conventional light aircraft the cabin is generally in zone 2 which is
subject to flash over only ... not direct attachment.

If lightning strikes an unprotected composite aircraft such as the forward
fuselage of a glider it will in all likelihood blow a hole through the skin
and attach to something metal (such as the rudder pedals). The arcing /
plasma etc can then cause an expansion of the air in the cavity (cockpit).
This phenomina has been responsible for blowing radomes off the nose of jet
aircraft. I assume that this is what blew the canopy out on this glider (I
still need to read the reports).

Composite structures in powered aircraft and helicopters are normally
protected from direct lightening strike in Zone 1 via a fine copper or
aluminium mesh embedded in the laminate (outer layer). These meshes are
generally manufactured by one of a couple of companies (Astrostike or
Exmet). The certification standards for gliders (JAR 22) do not however
require this as does say FAR 23 for light aircraft. It would be interesting
to know if these are isolated incidents (after all gliders don't make a
habit of flying near thunder clouds) or if it is more common than we might
all have imagined.


"Bill Daniels" > wrote in message
...
>
> "GM" > wrote in message
> oups.com...
> > Hello all in US-gliderland,
> > Some time ago, there was an interesting article in Soaring about a
> > glider being struck by a lightning. I seem to remember a photos of
> > scourched sneakers, a blown out canopy and other damage. Can anybody
> > tell me which issue of Soaring this was or if this article is available
> > online?
> >
> > Thanks,
> >
> > Uli Neumann
> >
>
> Did you see some BIG SPARKS lately, Uli?
>
> Bill Daniels
>

[Derrick Steed]

It would be interesting
to know if these are isolated incidents (after all gliders don't make a
habit of flying near thunder clouds) or if it is more common than we
might
all have imagined.=20
################################################## ####################

Try reading Philip Wills book in which he describes taking a wooden
glider into a CuNim and the consequences of that action - he landed the
glider, but it was a write off.

In the UK, it isn't always obvious that the large cloud you are under
has turned into a monster, although the first indication is usually the
difficulty one has in staying clear of it due to the off the clock lift
one encounters in that situation.

Rgds,

Derrick Steed

[Mike the Strike]

As both a glider pilot and a lightning guy, I have kept an eye on this
topic for quite a few years.

I was peripherally involved with the UK ASK 21 accident and received
some unpublished reports from a colleague who was one of the
investigators. The glider in this British incident became part of the
circuit of an unusually powerful positive lightning ground discharge.
It entered one wing, puncturing the fiberglass and flowing down the
control pushrods. The current was so high, it collapsed the pushrod
tubing. Arcing between metal fittings behind the pilots provided the
pressure that both deafened the pilots and blew the canopy off. Damage
to the wings was catastrophic. Investigators concluded that the
lightning current flowing through the glider was greatly in excess of
laboratory test currents used for certification of aircraft (although
gliders and other plastic aircraft are usually not subject to these
tests).

Most aircraft lightning strikes are cloud discharges triggered by the
plane itself and involve quite modest currents and energies. Glider
strikes usually also fall in this category. I inspected an ASW-27 that
was struck by lightning in South Africa a couple of years ago. The
discharge entered the nose, exited through the tail and left just a few
small holes with no major structural damage. Most electronic
instruments were smoked, however.

Interestingly, direct pilot injuries from the lightning seem to be
minimal.

If you are going to regularly fly around or into thunderclouds, I
recommend a strong metal glider and a freshly-packed parachute!

Mike