Indicated airspeed (IAS)

Definitions

• The direct instrument reading obtained from the airspeed indicator, uncorrected for variations in atmospheric density, installation error, or instrument error. Manufacturers use this airspeed as the basis for determining airplane performance. Takeoff
• Means the speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors.

References

• 14 C.F.R. Part 1, Federal Aviation Administration, 2026
• Airplane Flying Handbook, Federal Aviation Administration, 2021