What is indicated altitude?

Indicated altitude is defined as the altitude read directly from the altimeter when it is set to the local altimeter setting, which represents atmospheric pressure at sea level. This reading reflects the atmospheric pressure at the location where the measurement is taken and helps pilots determine their current altitude based on the local weather conditions.

Understanding this concept is essential because altitude measurements used in aviation must consider the atmospheric pressure variations due to weather changes. When an altimeter is set accurately to the local pressure, what the pilot sees is the indicated altitude. This is a fundamental aspect of flying, as it directly influences safety and navigation.

The other options describe different types of altitude measurements or corrections and do not align with the definition of indicated altitude. For instance, altitude corrected for temperature relates to pressure altitude adjustments, while vertical distance above the standard datum plane is a different concept related to reference points in aviation.