A very high pressure settled in Pacific NW:

KPSC 020453Z 31006KT 6SM BR BKN007 BKN075 M07/M08 A3066 RMK AO2
SLP389 T10671078

That's the highest that I've ever remember seeing.

I always thought that the NW seems to have larger pressure swings
(probably more so in Alaska). We can go from 2960 to 3060 in about two
days.

BTW, FAR 91.144 restricts flight operations when barometric pressure
exceeds 31 inch mercury. Any idea why? (note this restriction applies
to VFR traffic a well).

M wrote:

I don't believe VFR flight requires accurate altimeter adjustable for
barometric pressure. 91.205 only requires such altimeter for IFR
operations.

J. Severyn wrote:

I don't believe VFR flight requires accurate altimeter adjustable for
barometric pressure. 91.205 only requires such altimeter for IFR
operations.

J. Severyn wrote:

Heck,,, get out and go flying. The wings love the thick air and the
motor really LOVES it too.

M wrote:

M wrote:

The "why" is that the altimeter setting range on most altimeters doesn't
go past 31.00". Does anyone have an example of a NOTAM under 91.144?
(how restrictive is it).

The rules that apply in Canada are a bit more explicit: >
http://www.tc.gc.ca/CivilAviation/publications/tp14371/RAC/12-1.htm#12-12

Basically it says
- for enroute, set the altimeter to 31"
- for IFR approaches, set the altimeter to the actual altimeter setting
if able, otherwise set it to 31" and adjust the altitude minima (add
100' and 1/4 SM per 0.1" above 31.00")
- aerodromes which cannot report the actual altimeter setting are
restricted to VFR.
-"For aircraft operating VFR, no additional restrictions apply; however,
extra diligence in flight planning and in operating in these conditions
is essential. "

benford2@aol.com wrote:

The engine will produce more power with denser air, but
atomization of the fuel suffers in the cold and consumption can go up.
Condensation in the engine is much more pronounced in the cold, too,
and corrosion starts to set in if the thing isn't run until the oil's
hot enough to get rid of it. Here in Alberta the engine simply won't
get hot at -25

"M" jthome.com> wrote in message
news:1165038178.941152.61430@n67g2000cwd.googlegroups.com...

Actually got out and practiced in the pattern a little bit today with my
instructor, but since he isn't allowed to instruct in our clubs planes, we
were splitting time (we did my primary instruction through a different
club).

Jim Macklin wrote:

I can hardly see how it should affect VFR flights. Additionally if the
pressure is higher than 31 inch mercury and the altimeter is set to
3100, the true altitude would be higher than what's indicated by the
altimeter. For VFR flights this would almost never introduce any
problems. (Even for IFR terrain separation this allows a bigger margin
for terrain clearance).

The only problem I could think of is the mode C requirement for
altitude above 10,000 MSL, if someone flying without a mode C x-ponder,
set their altimeter to 3100, on day with pressure higher than 31"
mercury, and flying right near 10,000 feet indicated on their altimeter
:-)

"M" jthome.com> wrote in message
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