Which type of pressure is typically used by the altimeter?

The altimeter primarily relies on static pressure to determine altitude. Static pressure is the atmospheric pressure measured at a given point in the atmosphere, taken without any additional influences from airflow around the aircraft or variations caused by the aircraft's motion.

As an aircraft climbs or descends, the ambient air pressure changes, and the altimeter responds to these changes in static pressure. This allows the altimeter to calculate and display the aircraft's altitude relative to sea level or a predetermined pressure setting.

Other types of pressure are not suitable for altitude measurement. Dynamic pressure, for instance, relates to the pressure caused by the aircraft's motion through the air and is used in instruments like the airspeed indicator. Total pressure incorporates both static and dynamic pressures, typically acting in systems measuring airflow, while compressor pressure pertains to the pressure developed in a compressor in a different context, usually concerning engine performance rather than altitude measurement.