Thread: chain of events
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Old March 10th 07, 07:59 AM posted to rec.aviation.piloting
Dave S
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Default chain of events

KM wrote:
On Mar 9, 9:39 am, Dave S wrote:

KM wrote:


I dont know about the approach itself, but the power issue is very
believable. If the main transformer for the whole place let go, its VERY
likely that it takes 10 or more seconds for the generator to get up and
running. Also, if I understand right, the generators dont serve the
entire airport, just select facilities and one or two main runways.



Dave, you also have to understand that the ATC facilities are at two
separate locations.


I understand that perfectly. Tower in one place. VOR in another.
Localizer in a shack off the end of the runway. Glideslope in yet
another shack about 1000 feet beyond the threshhold off to the side.
These shacks and boxes may be hundreds or thousands of yards from each
other.

I also know that if the BIG transformer that steps down from the big
high tension lines lets go, as in.. the BIG one in the substation.. then
the whole grid downstream of that transformer drops offline. That can
include an airport.

I once was a volunteer fireman for about 10 years... in that time, we
had a big snake go slithering up equipment in a substation one night. I
guess the hum and warmth of the stuff was just tooo inviting to resist.
He completed a short circuit that took out power to thousands of homes,
caused a PCB oil fed fire and had the fire marshall's office initially
investigating it as a terrorist act until we found the charred skeleton
of the snake. (Pre 2001 but after 1994 - the first WTC). The transformer
bit is quite credible, and if you are ever near one when one lets go,
its an underwear changing event.

As for UPS and such.. I've seen UPS's on computers, and on some radio
gear, but nothing big enough to run an airport or hospital
stand-alone.. maybe there are enough little boxes in the shacks, but if
what NEWPS says is true, then I doubt it.

The local big city fire department, at one time, had a hardened concrete
2 story windowless dispatch center, with 2 sources of incoming power
on lines, PLUS a generator with over a week's worth of fuel, PLUS a bank
of batteries to run it all until the generator could kick over. That
struck me as robust...

But again.. something like this happens, with big iron yanking and
banking on the final approach course, after an explosion at an airport,
with a power loss.... and never heard a word about it except here.. hmmm..