[TowerTalk] planes and towers

[Gary - AB9M]

In the mid 80's or early 90's, State Farm Insurance was involved in 
upgrading their Corporate Headquarters Campus two-way radio system.  The 
antenna used was some 12 feet long which would extend above the clearance 
lights three feet above the four corners of the 13 story building which just 
happened to be 197 feet tall. When I went to submit the license application 
to the FCC, I noticed the LAT/LONG of the previous license was incorrect, 
showing the building which had stood at the corner of Veterans Parkway and 
Washington street in Bloomington, IL for over twenty-five years, to be 
several miles away near the south-west split of I-55 and I-74. Given the 
actual building proximity to the Bloomington Airport (BMI), I was required 
to also notify the FAA of any changes in frequency or antenna height.

Several weeks later I received a call from the FAA's Chicago Office 
informing me that I had to reduce my tower height by sixty feet! When I 
replied, "you don't understand", the FAA official said, "NO YOU DON'T 
UNDERSTAND, your tower is too close to the end of the Bloomington Airport 
runway"! I then replied, the antenna support structure is not the type tower 
you envision, but rather it is a building tower which has been in place for 
over twenty-five years".

I was then required to have the site surveyed by a local engineering group. 
Included in the survey  were the direction and distance from the center of 
the runway to the clearance lights, antenna, and any other object which 
might project above the clearance lights. In addition to the FAA permit for 
the radio antenna, State Farm holds a seasonal permit to erect and extend a 
crank up pole supporting a Christmas tree shaped configuration of colored 
bulbs.

The net result of the survey of the State Farm Executive Tower at One State 
Farm Plaza, Bloomington IL, was a "Notice To Airmen" published by the FAA, 
which changed take off and landing angles to and from BMI, as well as 
increasing the "free circling plate height" of BMI to 1244 feet AMSL.

Unfortunately sometimes the FAA does not have ALL the facts or the correct 
facts for pilots flying near our antenna structure.  As it was explained to 
me, an aircraft flying under limited visibility conditions has a two hundred 
foot clearance buffer in the "free circling plate height".  Changes in 
atmospheric pressure or incorrect setting of the altimeter can put a plane 
lower in height and into a tower in the flight path to the end of the runway 
if the tower location and height are not accurately reported.


73 & DX,

Gary - AB9M

-----Original Message----- 
From: Courtney Judd
Sent: Thursday, September 18, 2014 1:30 PM
To: Towertalk at contesting.com
Subject: [TowerTalk] planes and towers

Looking at the W9ZUC incident and the clip below it about the
duster/tower made me think back about several incidents with mine. I
live directly in a MOA (military operating area) and 20 or so years ago
maybe more a F4 blew over my tower while I was working at the top
exceeding the speed of sound. He put a sonic boom on me which i would
have jumped off if i had not been securely fastened to the tower.
Normally it is illegal to create a sonic boom over the continental US
but they had a waiver in order to re-certify the F4's before giving them
to the national guard.  this turned out to be pretty regular for the
next several months. Another time I was up at daylight standing on my
porch looking at my 140' tower which was hidden in fog from about 50 ft
and up when i could hear helicopters coming my way. I could tell that
they were heading right at my tower. They were flying right at the
bottom edge of the fog. They came into my view a couple of hundred ft
from the tower. One broke left; the other went right. I thought  was
going to witness a big one for a minute!  Scary! 73's Cort K4WI
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk