What are common consequences of a pitot-static system failure on airspeed and altitude readings?

• A. Altitude readings may be affected due to static pressure errors.
• B. A/S may read erratically, freeze, or swing to extreme values; altitude readings may also be affected due to static pressure errors.
• C. A/S readings remain accurate; altitude readings are unaffected.
• D. Only engine instruments are affected.

Answer: (B)

A pitot-static system provides the signals for both airspeed and altitude by using dynamic pressure from the pitot tube and ambient static pressure from the static port. When this system fails, those signals become unreliable, so the readings that depend on them behave accordingly. If the pitot tube is blocked but static pressure is still sensed, the airspeed indicator loses its dynamic pressure input and can read zero, wander erratically, or swing to extreme values as the remaining pressures shift with changes in actual speed. If the static port is blocked or leaking, the altimeter and the vertical speed indicator rely on static pressure and will no longer track true altitude or rate of climb, often freezing or showing incorrect readings. Since airspeed depends on the difference between pitot and static pressures, and altitude depends on static pressure, a pitot-static failure typically produces simultaneous issues in both airspeed and altitude readings. Engine instruments aren’t the primary concern in this failure mode.