What symptom might indicate a blocked pitot tube in flight?

What symptom might indicate a blocked pitot tube in flight?

• A. Consistently high engine RPM
• B. Erratic or zero airspeed readings or instrument failure
• C. Stable altitude readings
• D. Rapid airspeed increase

Answer: (B)

The pitot tube feeds ram air pressure to the airspeed indicator. If it becomes blocked, that pressure signal is lost or distorted, so the airspeed indicator can read erratic values or drop to zero, and other instruments that rely on pressures from the pitot-static system may also show failures or inconsistencies. That direct disruption of the airspeed signal is what this symptom describes, making it the best indicator of a blocked pitot tube. Other options involve engine performance, altitude, or rapid speed changes that aren’t specific signs of a blocked pitot tube.

The pitot tube feeds ram air pressure to the airspeed indicator. If it becomes blocked, that pressure signal is lost or distorted, so the airspeed indicator can read erratic values or drop to zero, and other instruments that rely on pressures from the pitot-static system may also show failures or inconsistencies. That direct disruption of the airspeed signal is what this symptom describes, making it the best indicator of a blocked pitot tube. Other options involve engine performance, altitude, or rapid speed changes that aren’t specific signs of a blocked pitot tube.