Airspeed Calibration & Error Solver (IAS, CAS, EAS, TAS & Mach)
Convert Indicated Airspeed (IAS) to Calibrated (CAS), Equivalent (EAS), True Airspeed (TAS), and Mach.
Input Parameters
Instrument and position correction from aircraft POH calibration chart
Calculation Results
Formula & How Airspeed Calibration & Error Solver (IAS, CAS, EAS, TAS & Mach) Works
Indicated Airspeed (IAS) measures dynamic pressure at the pitot tube. Correcting for installation/position error gives Calibrated Airspeed (CAS). Correcting for high-speed air compressibility gives Equivalent Airspeed (EAS). Correcting for ambient air density ratio (sigma) yields True Airspeed (TAS)—the actual speed of the aircraft through the air mass.
- Enter Indicated Airspeed / IAS (knots) (KIAS): Input your target parameter value.
- Enter Pitot-Static Position / Instrument Error (knots) (kts): Input your target parameter value.
- Enter Pressure Altitude (ft) (ft): Input your target parameter value.
- Enter Outside Air Temperature / OAT (°C) (°C): Input your target parameter value.
- Apply Formula: Calculate using
CAS = IAS + Error | EAS = CAS × [1 - 0.5(1-δ)M²] | TAS = EAS / √σ | Mach = TAS / a. - Review Results: View exact computed answers, metrics, and worked mathematical proofs.
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Frequently Asked Questions (FAQs)
Why is True Airspeed higher than Indicated Airspeed at altitude?
Because air density decreases with altitude, fewer air molecules enter the pitot tube for a given speed. The aircraft must fly faster through the air (higher TAS) to generate the same dynamic pressure reading on the ASI (IAS). TAS increases roughly 1.5% to 2% per 1,000 ft of altitude.
When does compressibility become significant?
Compressibility effects become noticeable above 200 knots and significant above Mach 0.4 (approx 250 KTAS), where ram air compression in the pitot tube causes the ASI to read slightly higher than actual Equivalent Airspeed.
Authoritative Standards & Verified Reference Citations
Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:
CASR Part 91 general operating and flight rules, Part 121 fuel reserves, and flight crew licensing standards.
Aviation weather services, standard atmosphere (ISA) profiles, METAR/TAF aerodrome weather reports.
Aeronautical Information Publication (AIP), En Route Supplement Australia (ERSA), and airspace procedures.
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