Altimetry and Atmospheric Pressure Concepts - Video

15 vocabulary flashcards covering altimetry concepts, pressure vs. density altitude, true altitude, and related instruments.

Altimeter

An instrument that measures altitude by sensing ambient pressure via the static port and converts pressure changes into altitude with three hands.

Altimeter setting

The pressure value entered into the altimeter's Colesman window to compensate for nonstandard pressure and produce accurate indicated altitude.

Station pressure

The actual atmospheric pressure at a location, before any sea level correction, used to derive the altimeter setting.

Indicated altitude

The altitude shown by the altimeter after applying the current altimeter setting; represents altitude above mean sea level under standard conditions.

Pressure altitude

The altitude the aircraft would indicate if the altimeter were set to standard pressure (29.92 inHg); reflects nonstandard pressure conditions.

Density altitude

Pressure altitude corrected for nonstandard temperature; higher density altitude means thinner air and reduced engine and wing performance.

True altitude

The actual height above mean sea level; affected by temperature causing expansion or contraction of the air column.

Static port

An opening that senses ambient air pressure for the pitot-static instruments; can be blocked, causing errors in multiple instruments.

Colesman window

The altimeter setting window used to input the station pressure to adjust indicated altitude.

Surface analysis chart

A weather chart showing areas of high (H) and low (L) pressure; used to explain changes in outside pressure and altimeter readings.

Standard pressure

The reference sea-level pressure of 29.92 inches of mercury used in defining pressure altitude under standard conditions.

Pressure altitude conversion

The process of converting indicated altitude to pressure altitude using the current altimeter setting; indicates how high or low the airplane thinks it is under nonstandard pressure.

Standard temperature

ISA sea-level temperature of 15 C (59 F) and a 2 C per 1000 ft decrease with altitude; used to compute density altitude.

Outside air temperature (OAT)

The actual air temperature outside the aircraft, used with pressure altitude to determine density altitude and engine performance.

Vertical Speed Indicator (VSI)

An instrument connected to the static port that shows the rate of climb or descent in feet per minute by monitoring the rate of pressure change.