----- Original Message -----
From: "Tower" <email@example.com>
Sent: Tuesday, December 21, 2004 4:11 PM
Subject: Re: [TowerTalk] Collapsed KFI Tower -- Impact of Coax?
> Even tall, unguyed structures tend to fall in on themselves although they
> would form as close a knit pile as the guyed tower.
I don't know that this statement is true. Unguyed structures tend to lay out
flat (kinked, it's true, but the final position is usually laid out). If
you have some analysis that shows otherwise, I'd love to see it (because
this question comes up a lot).
> The acelleration of a tall tower tipping over will cause the top half of
> to bend back on itself.
This is indeed the case (and, interestingly, it also happens when a pencil
point breaks). It's particularly noticeable on masonry columns (smokestacks
are a good example), as they break into segments on the way down. However,
they don't collapse in a heap at the bottom, they just flex and break.
> I'd sure hate to have the liability of a tower near final approach to any
That tower has been there for >50 years and only been hit once before (a guy
wire strike, I believe). It's well marked on the charts, and granted, it's
hard to see in the daytime, but, then, that's why it's on the charts. There
are worse hazards near airports. Hills off the end of the runway, stuff like
that. Power lines across canyons. All those places where the approach plate
says "successful go-around unlikely". In the LA Basin, I'd worry more
about hitting another plane or busting some controlled airspace boundary
because you were talking to the wrong controller on the radio and getting a
nasty note from the FAA.
Since the tower was there before the airport, there's not much liability
that attaches to its continuing existence. Whether it was a good idea to
build parking lots and industrial space underneath it is another question,
but from the photos I've seen so far, the damage to surrounding structures
is limited (if any). So far, it looks like the engineers did a decent job
(after all, having an airplane fly into your tower is a fairly unlikely
There has been some bickering mentioned about why there weren't strobes on
the tower. (Maybe Clear Channel doesn't want to spend the bucks?)
And, it used to be a LOT easier to see from the air, because it was in the
middle of this huge vacant lot, which sort of stood out as you followed the
I5 freeway north or south (the classic IFR (I follow roads) technique).
Personally, I preferred flying a bit farther east (under the controlled
airspace) or west (over the coastline). These days, you'd have to watch out
for the Disneyland prohibited airspace (if it's still in force).
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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