ATIS Terminology

[MFD4305]

My local AFB ATIS uses the following terms after the 'altimeter' reading:
"Pressure Altitude" and "Density Altitude." Can someone enlighten me on what these mean?
Thanks!

 

[mibzzer15]

Pressure altitude = Pressure altitude - Wikipedia, the free encyclopedia

Density alititude = Density altitude - Wikipedia, the free encyclopedia

 

[MFD4305]

Thanks!

Thank you for the prompt and thorough response, '15. I'm a bit embarrassed that I didn't find those entries myself, but I appreciate your help!

 

[pinballwiz86]

I was just wondering about pressure altitude myself. I was listening to Fort Leonard Wood's ATIS while I was parking my car. Funny enough, ATIS said Forney air field is closed. But, I could hear them running maneuvers on mil air. Probably just means the air field is closed to the civies.

 

[Colin9690]

Pressure and density altitudes are useful for predicting aircraft performance, and many fields only include them in the ATIS if conditions are exceptionally crappy in regard to performance. Many fields out west at high elevations include it continuously, since high elevation+hot and humid air = high density altitude = poor aircraft performance (piston aircraft only).

 

[majoco]

since high elevation+hot and humid air = high density altitude = poor aircraft performance (piston aircraft only).

Hot'n'high is a limiting factor with turboprops too, so I guess it is with any turbine. Sometimes even APU's have trouble starting!

 

[patrauma_nurse]

ATIS usually includes density and pressure measurements (usually referred to as altimeter) where weather is extremely variable or where temperatures are maintained at extreme levels. They are used by prop driver aircraft to help pilots predict settings such as prop pitch and blade rotations when attempting landing or takeoff procedures. Commercial jet aircraft are not so much affected by these conditions but are often useful in predicting turbulence and windshear which might affect performance. The term altimeter is somewhat of a misnomer as these conditions are also affected by the mean altitude of the airport above sealevel where pressure and density factors may vary greatly from those at sea level.