Simviation Forum - A few questions guys

Sep 14^th, 2003 at 4:25pm

gilbates Offline
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Fly Hyperion
UK

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Work with me here guys please , yes yes i should know the answers but ..... i dont ok

what does QNH stand for exactly

what does NOSIG mean

and when given Alt settings by ATC which are pretty important ( on-line that is ) my plane shows something like 29.?? mb or i think its millibars anyway but they give it to me differently , they give the other way .... er which evades me also , the name i mean

yes yes all pretty vague but ya get my drift , is there a simple mathematic conversion so i can change my Altimeter and set the correct reading

did yiu konw taht aoccdrnig to rscheearch at an&&Elingsh uinervtisy, it deosn't mttaer in waht oredr&&the ltteers in a wrod are, the olny iprmoetnat tihng&&is taht the frist and lsat ltteer is in the rghit&&pclae. The rset can be a toatl mses and you can sitll&&raed it wouthit porbelm. Tihs is bcuseae we do not&&raed ervey lteter by it slef but the wrod as a wlohe.&&Cool eh?&&

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Reply #1 - Sep 14^th, 2003 at 4:44pm

ozzy72 Offline
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NOSIG-means No Significant Change in the weather.
QNF is mean sea level altimeter pressure setting.
Okay if you want to get pressure settings in millibars, you have to change one of the settings in options, I can't remember which one, but it'll stop giving it in millimeters or inches of mercury (I can't remember which as I haven't changed it for about a year Roll Eyes

).

Ozzy

There are two types of aeroplane, Spitfires and everything else that wishes it was a Spitfire!

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Reply #2 - Sep 14^th, 2003 at 4:47pm

Nexus Offline
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QNH is the atmospheric pressure at nautical height, ie: Sea level

NOSIG: Should mean "No Significant change", and that term is used to describe the wheater conditions, I believe.

The 29.92 is NOT millibar. The term aviators would use is Inches of Mercury (inches HG)
That term is used in America. Here in Europe we have the Hecto Pascal (HPA)

Millibar is also used in aviation, but 1mb is 100 pascals.
So 1013 HPA is 1.013mb

The standard is:
Inches HG - 29.92
HPA: 1013

Hope this helps!
8)

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Reply #3 - Sep 14^th, 2003 at 4:50pm

Nexus Offline
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Aww bugger...Ozzy shows who's the daddy on the forums, beat me by 3 mins!
Grin

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Reply #4 - Sep 14^th, 2003 at 5:04pm

ozzy72 Offline
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Pretty scary huh?
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I aim to be an annoying know-it-all Nexus Wink

There are two types of aeroplane, Spitfires and everything else that wishes it was a Spitfire!

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Reply #5 - Sep 14^th, 2003 at 5:06pm

gilbates Offline
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hahah Thanks guys , thats why i like it here , you always make me laugh ..... awww bugger indeed

thanks for the replys and i know its picky but QNH means Atmospheric pressure at nautical height then why the Q ? the big word begins with an A Grin

and i`l have a look to see if i can change the pressure millibars and inches thingy

Very technical me with terminology aint i Grin

did yiu konw taht aoccdrnig to rscheearch at an&&Elingsh uinervtisy, it deosn't mttaer in waht oredr&&the ltteers in a wrod are, the olny iprmoetnat tihng&&is taht the frist and lsat ltteer is in the rghit&&pclae. The rset can be a toatl mses and you can sitll&&raed it wouthit porbelm. Tihs is bcuseae we do not&&raed ervey lteter by it slef but the wrod as a wlohe.&&Cool eh?&&

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Reply #6 - Sep 14^th, 2003 at 5:11pm

Nexus Offline
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The greater of two evils...

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Quote:

I aim to be an annoying know-it-all Nexus Wink

Glad I'm not alone Grin

Have a great one

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Reply #7 - Sep 14^th, 2003 at 5:29pm

Nexus Offline
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The greater of two evils...

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Quote:

hahah Thanks guys , thats why i like it here , you always make me laugh ..... awww bugger indeed

thanks for the replys and i know its picky but QNH means Atmospheric pressure at nautical height then why the Q ? the big word begins with an A Grin

and i`l have a look to see if i can change the pressure millibars and inches thingy

Very technical me with terminology aint i Grin

Allright, the QNH is an OLD abbreviation still being used. Originated from the era of wire-less communications (morse codes and stuff)
Note: The letters in the abbreviation has nothing to do with their actual meaning

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Reply #8 - Sep 14^th, 2003 at 8:31pm

zcottovision Offline
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If you're interested in learning how to read a METAR properly, I'd recommend visiting http://aviation.weathersa.co.za/codesexpl.htm ! They have pretty much everything you need to know about reading a proper METAR, and it really helps!

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Reply #9 - Sep 14^th, 2003 at 9:06pm

OTTOL Offline
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QNH is Quasi-nonHydrostatic. It is read in millibars, as opposed to Standard (US) which is expressed in Inches of Mercury. It's importance has to do with proper indication on your altimeter. Pressure constantly changes, and affects the altimeter indication. One worse case example would be, if you traveled from one airport to another, perhaps 100 miles away. If the temperature at your destination airport is much lower, your altimeter indication will indicate an altitude which is HIGHER than your ACTUAL altitude. ie: you may be at 50ft OR LESS! when your altimeter reads 1000ft. This would be an extreme example, but I think you can see the importance. Sometimes 50ft can spell a LIFETIME! Especially in mountainous terrain. Try to find a thread titled "what does "29.92" mean", it answers all you want to know about the subject, and has some interesting dialogue! Grin

http://www.srh.noaa.gov/elp/wxcalc/altimetersetting.shtml

« Last Edit: Sep 15^th, 2003 at 3:00am by OTTOL »

.....so I loaded up the plane and moved to Middle-EEEE..........OIL..that is......

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