Calibrated Airspeed (CAS) is defined as the indicated airspeed corrected for which factors?

• A. Indicated airspeed corrected for installation and instrument error
• B. True airspeed corrected for altitude
• C. Indicated airspeed corrected for altitude
• D. Calibrated airspeed equals true airspeed

Answer: (A)

Calibrated airspeed is the indicated airspeed corrected for instrument and installation errors. The airspeed indicator can be biased by how the instrument is calibrated (instrument error) and how the pitot-static system is installed on the aircraft (installation error). Correcting for these biases gives a reading that represents the speed through the air with perfect instrumentation and mounting. Altitude and density effects influence true airspeed and equivalent airspeed, but those corrections are not part of the definition of calibrated airspeed. So the best description is IAS corrected for instrument and installation error.