that is your altimeter setting, it gives you the proper altitude below 18'000 feet, and is used by all aircraft to maintain proper altitude seperation, this obviously changes with the weather, but above FL180 it becomes standard 2992
thats a basic thing to it, prob a few mistakes, but i will let someone else give a full explination hope it helps a little

Errrrrrrrrrr.  That would be 29.92 inches of mercury.  

If the barometric pressure was at 29.92 millibars, you wouldn't be too comfortable.  In fact, your head would probably explode.

Malibu,

You can also adjust the barometric pressure by going into the weather settings and changing it.  It can get tiresome hearing "29.92" all the time.  Better yet, if you have the courage to fly in real-world weather, you're certain to hear different readings when flying from one place to another.

I sure hope EMH8 isn't flying a real airplane. I fly a jet all over the world, and have experienced a "standard" day (pressure 29.92), quite frequently, and my head is still intact. Maybe I should start wearing a helmet!
All of you, so far, have missed the mark. "Pressure Altitude" is the indication on your altimeter when the Colesman window is set to indicate 29.92". Standard pressure is 29.92 inches of mercury or QNH (quasi-monohydrostatic) 1013.2 millibars. The reason I mention QNH is not to impress you with my wisdom, but because it often clarifies a simple issue with students transitioning into the U.S. system and it's terminology.       
I think, to answer the root question though, with your airplane sitting on the runway of whatever airport you choose, set the altimeter to indicate the known elevation of that particular airport. The indication in the Colesman window(the little tiny window in the face of the altimeter) is the correct altimeter setting.

Okay, okay, okay....one at a time:

"I fly a jet all over the world, and have experienced a "standard" day (pressure 29.92), quite frequently, and my head is still intact. Maybe I should start wearing a helmet!  "

He wasn't saying that 29.92 can't happen.  He was saying that I mis-spoke when I said that 29.92 means 29.92 millibars.  (And he was correct!)

"I think, to answer the root question though, with your airplane sitting on the runway of whatever airport you choose, set the altimeter to indicate the known elevation of that particular airport. "


That sounds an awful lot like my answer of:

"When ATC gives you an altimeter setting of "2992"...This gives you an accurate reading at that airport of what you have to set your altimeter to in order for it to read "0000 feet" when you're on the ground there. "

yep...I'm way off.

Rifleman, do I even want to know why you've got that so easily accessible?  :::grin:::

Any question deserves the beginning of the information hwy before you try to start a trip in the middle.....I can usually find stuff on here....... 8)

Otto,

No worries!  Welcome to the forum..............

Erik