Getting high...

scottd

scottd

Pre-takeoff checklist
Joined
Dec 6, 2005
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117
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Charlotte, NC
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scottd
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Well, I just got a pretty good snow storm yesterday, with winds and drifts. I am aiming to get out and fly on Tuesday!
 
Ay caramba!! :eek:

No wonder the local forecasters are waffling- we will probably get hammered here, but it'll be hard to say when it will be worst.


Already decided to postpone tomorrow's work... :D
 
That makes me think about FAR 91.144
Temporary restriction on flight operations during abnormally high barometric pressure conditions.

(a) Special flight restrictions. When any information indicates that barometric pressure on the route of flight currently exceeds or will exceed 31 inches of mercury, no person may operate an aircraft or initiate a flight contrary to the requirements established by the Administrator and published in a Notice to Airmen issued under this section.
(b) Waivers. The Administrator is authorized to waive any restriction issued under paragraph (a) of this section to permit emergency supply, transport, or medical services to be delivered to isolated communities, where the operation can be conducted with an acceptable level of safety.
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So is everyone grounded or is there some exception made? How about for your departure Bruce?
 
You're right, Scott. 30.50. Sigh. Late at night......
The Gradient was >0.5. eg when I got to Peoria, it was 29.90 or the like.
Wind's a howling....
 
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scottd said:
Bruce,

Are you sure you mean 31.50" and not 30.50? Assuming you are talking about Thursday, January 27th. The highest altimeter I could find was at 15Z and that was 30.42".

KJAC 271452Z 00000KT 10SM OVC014 M07/M08 A3042
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that's still high! Highest I had experienced was around 3010. Then I flew all the way to california and back. 3076 was the highest we had. pretty ridiculous to me!

I can't even imagine 31 or higher, it's got to be kinda crazy spinning the altimeter to its limits
 
So much for this forecast being clear! This Tuesday morning, it is overcast and snowing where I am in Montana. And it is 30.63...
 
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I have a question that I'm not sure I'll be able to articulate well, but here goes: These pressure measurements are made at the surface AFAIK, but surface elevation doesnt seem to have an effect on the contours, i.e. the increasing elevations dont seem to indicate decreasing pressure. In fact, the current prog chart shows a ridge of high pressure along the rockies. Does this make sense?
 
That makes sense. I thought they may have to be normalized to sea level pressure. So flying through those areas, you would use the numbers on the prog chart as your altimeter setting, if they use a geopotential of 0 MSL.
 
scottd said:
Definitely not. Take a look at my two minute video tip that I posted. The altimeter setting is NOT the same as a reduction to sea level pressure.
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Thanks, that was a great video! I never understood why SLP was given in addition to altimeter setting; seemed redundant to me, but now it makes sense.
 
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