What could be a sign of a malfunctioning pitot-static system?

Erratic altitude readings are a strong indicator of a malfunctioning pitot-static system. The pitot-static system is responsible for measuring air pressure to provide crucial flight data, including altitude and airspeed. If there are irregularities in the altitude readings, it suggests that the system is experiencing issues, such as blockages in the static line or inaccuracies in the pitot tube.

On the other hand, accurate airspeed readings, consistent vertical speed indications, and normal instrument function would generally point to a properly functioning pitot-static system. Any deviations from expected readings, such as erratic altitude measurements, can help pilots identify problems that could affect flight safety and performance, necessitating further troubleshooting and inspection.