How does the altimeter react to a blocked pitot tube?

When a pitot tube gets blocked, it affects the airspeed indicator but has specific implications for the altimeter. In this case, the altimeter measures static pressure, which is provided by the static port and not directly affected by a blocked pitot tube. However, if we focus on the dynamics of the situation, when the pitot system is blocked, the altimeter will essentially "freeze" at the last altitude it read before the blockage occurred. This means it will maintain that last reading until the blockage is resolved, and the aircraft climbs or descends.

This behavior is crucial for pilots to understand during flight operations since a blocked pitot tube can lead to unreliable airspeed readings, but the altimeter retains the last known altitude as a reference until there is a change in atmospheric pressure or a resolution of the blockage.