There are also "bridge" UPSes that store energy in flywheels and
ultracapacitors.

I'm no UPS or Power engineer, but isn't the flywheel bridge used to
"bridge" the time it takes for a generator to come online. I was not
aware that there are UPS's using this technology. While ultracaps do
store energy, they are typically only sized to maintain an output load
for a period of about 30 seconds in the flywheel bridge. This
application isn't really a UPS per se, though would be awesome to
prevent the failure Capt Doug speaks of. My specialty isn't UPS's,
rather telecom, so take it all with a grain of salt.

Reading Capt Dougs story makes one wonder about the reliability of the
"things" we rely on for our navigation, communications etc while
flying around. I am a new pilot and would be kinda bummed out if on
final at night and the runway lights went out. Though I probably
shouldn't be, I think I am dependent upon the runway edge lighting to
make a landing at night... Maybe I am wrong... but dang that would be
an eye opener for sure if those things went out on me while on short
final, or even worse, just seconds before touchdown.

Mike Alexander
PP-ASEL
Temecula, CA
See my online aerial photo album at
http://flying.4alexanders.com

I don't know whether a lot of the original story was tongue-in-cheek, or
whether it just got-a-little-better with each retelling; but I really can
not believe the part about the nav-aids going off line.

Basically, the runway and taxiway lighting systems need a lot of power, so I
would not be able to categorically deny any assertion. There are a lot of
budgetary and philosophical considerations involved, so a compromise between
cost and downtime is plausible--maybe even probable.

However, the nav-aids (localizer, glideslope, and marker beacons) require
very little power at each location--probably less than a personal computer.
And a TVOR requires very little more; so, like several others, I am willing
to postulate that the story, as told, is false.

Peter
Just my $0.02