Which statement defines Calibrated Airspeed (CAS)?

• A. IAS corrected for instrument errors only.
• B. IAS corrected for instrument errors, position error, and installation errors.
• C. IAS read directly from the pitot tube with no corrections.
• D. Ground speed adjusted for wind.

Answer: (B)

Calibrated Airspeed is the indicated airspeed corrected for instrument errors, position error, and installation errors. The airspeed indicator shows IAS, but that value is affected by inaccuracies in the instrument itself and by how the pitot-static system is mounted and routed on the aircraft. Instrument errors come from the instrument’s own calibration and mechanism; position error arises because the pitot tube and static ports sample air that can be disturbed by the airplane’s shape and attitude; installation errors include the plumbing, leaks, and other setup factors that alter the pressure signals. Applying these corrections yields CAS, which more accurately represents the pressure-based speed of the aircraft. Uncorrected IAS would ignore these real-world effects, and ground speed is a different quantity altogether.