Helicopter Private Pilot Practice Exam 2026 – Complete Test Prep

When the pitot tube becomes clogged in the Schweizer 300c, it directly impacts the airspeed indicator, causing it to become unreliable. The airspeed indicator operates by measuring the dynamic pressure of the air entering the pitot tube, which correlates to the aircraft's speed through the air. If the pitot tube is blocked, it cannot accurately measure this dynamic pressure; thus, the airspeed reading will be incorrect.

While the clogged pitot tube does not affect the altimeter or vertical speed indicator directly, as they use static pressure for their measurements, it specifically compromises the accuracy of the airspeed indicator. In a helicopter, maintaining accurate airspeed is critical for safe operations, particularly during maneuvers like takeoff, landing, and autorotation.

The other instruments, which rely on static pressure rather than dynamic pressure from the pitot tube, would remain functional, maintaining their reliability unless influenced by separate factors.