Don't always believe the AWOS...

Machines are much better at precise measurements than people. I'm not
sure I could tell the difference between 200 OVC and 700 OVC by eye, and
I'm sure I couldn't between 1000 and 2000.

I don't claim to be expert at that, either, but when the previous a/c
reported breaking out at minimums, 200 feet, the observer continued to
report 700 feet.

vince norris

Most weather ceilings are now determined by machine (a laser
ceilometer), even if it's relayed by a human. The old balloon method
that determined ceilings by how long it took for the balloon to enter
the clouds is only used these days at those sites that don't have a
working ceilometer.

JPH

vincent p. norris wrote:
Nothing, but nothing, beats a set of human eyeballs
in the location right now to report what the weather is doing.


Human eyeballs can't always be trusted, either. Returning home to a
non-towered field shortly after dark, I was told by Unicom that the
ceiling was 700 feet. But the aircraft just ahead of me reported
breaking out at minimums--200 feet. I, too, broke out at 200 feet.

The observer was at the terminal, half a mile from the end of the
runway.

vince norris

I supposed balloons were used only for atmospheric sounding anymore.
I didn't know they were still used *anywhere* as a substitute for =
ceilometers.
I'm pretty sure I remember ceilometers being deployed 45 or more years =
ago.

"J Haggerty" wrote in message =
news:Qk_Bd.4488$2_4.750@okepread06...
Most weather ceilings are now determined by machine (a laser=20
ceilometer), even if it's relayed by a human. The old balloon method=20
that determined ceilings by how long it took for the balloon to enter=20
the clouds is only used these days at those sites that don't have a=20
working ceilometer.
=20
JPH
=20

"John R. Copeland" wrote in
:

I supposed balloons were used only for atmospheric sounding anymore.
I didn't know they were still used *anywhere* as a substitute for
ceilometers. I'm pretty sure I remember ceilometers being deployed 45
or more years ago.

Nope, they're still around. Balloons are a lot cheaper than ceilometers,
especially if you only need an exact ceiling now and then.

--
Regards,

Stan

"Steven Barnes" wrote in
m:

I got my IR last August and finally got to log my 1st post-checkride
actual approach. All while the airport I was landing at was reporting
10 miles and clear below 12,000. More like 1,200. All day long this
place was reporting clear skies. All day long it varied between 1,200
and 1,700.

I've also seen the ASOS reporting fog, low visibility and low ceilings,
and had the airport in sight 30 miles out, and no problems all the way
in. Automated systems do lie sometimes, but they're better than nothing.

--
Regards,

Stan