What is the primary purpose of an altimeter in an aircraft?

The primary purpose of an altimeter in an aircraft is to measure the altitude of the aircraft above sea level. An altimeter works by detecting changes in air pressure; as an aircraft ascends, the atmospheric pressure decreases, and the altimeter converts those pressure readings into an altitude reading. This is crucial for pilots to maintain safe altitude levels, comply with air traffic control instructions, and avoid terrain.

Understanding an aircraft's altitude is essential for ensuring safe navigation and operation in varying airspace and weather conditions. This capability is particularly vital during takeoff, landing, and in-flight maneuvers, where precise altitude management is necessary to promote safety and efficiency.