All aircraft are equipped with a small hole in the surface of the aircraft called the static port. The air pressure in the vicinity of the static port is conveyed by a conduit to the altimeter and the airspeed indicator. This static port and the conduit constitute the aircraft's static system. The objective of the static system is to sense the pressure of the air at the altitude at which the aircraft is flying. In an ideal static system the air pressure fed to the altimeter and airspeed indicator is equal to the pressure of the air at the altitude at which the aircraft is flying.