Which instrument would be affected if the pitot tube got clogged?

The airspeed indicator relies on the pressure measurements provided by the pitot tube to determine the speed of the aircraft relative to the surrounding air. The pitot tube measures dynamic pressure created by the airflow over the aircraft as it moves forward. If the pitot tube becomes clogged, it will prevent accurate measurements of this dynamic pressure, leading to incorrect readings of the airspeed. This malfunction can result in the airspeed indicator displaying zero or an inaccurate speed, which is critical information for safe flight operations.

In contrast, while the altimeter measures atmospheric pressure and could be affected by other factors like changes in weather, it does not depend on the pitot tube. Similarly, the vertical speed indicator measures changes in altitude over time and uses static pressure information, not dynamic pressure from the pitot tube. Lastly, the artificial horizon, or attitude indicator, uses gyroscopic principles to show the orientation of the aircraft and is unaffected by any issues with the pitot tube.