Indicated altitude

Indicated Altitude - Altitude data shown on the altimeter using the current altimeter setting input by the pilot.
True Altitude - Height above mean sea level (MSL).
Absolute Altitude - Height above ground level (AGL).

indicated altitude
The altitude as shown by an altimeter
INS (Inertial Navigation System)
A totally self-contained system which requires no information from outside references.

Indicated Altitude
The altitude as shown by an altimeter. On a pressure or barometric altimeter it is altitude as shown uncorrected for instrument error and uncompensated for variation from standard atmospheric conditions.

Indicated altitude, this is the altitude that is read directly from the altimeter when it is set to the current altimeter.
True altitude, the vertical distance from the aircraft above sea level, the actual altitude.

Cloud layers at the indicated altitude above the airport
Temperature 15, dewpoint 13
Temperature and dewpoint in degrees Celsius.

This brings us to the subject of calibrated altitude and indicated altitude.

Density altitude is pressure altitude (pressure altitude is indicated altitude against 1013.25 hPa / 29.92 in HG) corrected for non-standard atmosphere temperature.

Note the altitude and the heading of the airplane, as we will strive to maintain both during slow flight. (I like to use an indicated altitude of 3,500 feet and one of the four cardinal headings - north, south, ...

SAY ALTITUDE- Used by ATC to ascertain an aircraft's specific altitude/flight level. When the aircraft is climbing or descending, the pilot should state the indicated altitude rounded to the nearest 100 feet.

To determine pressure altitude from the altimeter, place the altimeter setting indicator at standard sea level pressure (29.92 inches) and read the indicated altitude which will also be pressure altitude.

A flying arrival into colder conditions means actual altitude is lower than indicated altitude.
Proper crosswind control positions are more vital than ever on a slick runway.

See also: Weather, Aircraft, Aviation, Altitude, Pilot