What do static ports on an aircraft measure?

Static ports on an aircraft are crucial components that provide accurate measurements necessary for various flight instruments. Their primary function is to measure atmospheric pressure outside the aircraft. This atmospheric pressure is vital for the operation of altimeters, airspeed indicators, and vertical speed indicators, which rely on the difference between static pressure and other pressures (like dynamic pressure) to function correctly.

When the aircraft is in flight, the static pressure measured by the static ports allows these instruments to perform essential calculations, helping the pilot determine altitude, airspeed, and the rate of climb or descent. The understanding of atmospheric pressure as measured by static ports is foundational in safely navigating and managing the aircraft's performance, especially when considering changes in altitude and the resulting variations in air pressure at different flight levels.