Airspeed

What's the relationship between IAS and CAS?

Calibrated airspeed (CAS) is calculated by correcting indicated airspeed (IAS) for instrument and position errors, and this correction is typically done using a calibration table provided in the Pilot Operating Handbook (POH) or other aircraft specifications.

Calibrated airspeed (CAS) is typically defined per aircraft type, not per individual plane.

When to use CAS?

What we read from the Airspeed Indicator is the IAS. CAS need to be looked up when calculating true airspeed.

When is CAS the same as TAS?

When flying at sea level under International Standard Atmosphere conditions (15 °C, 1013 hPa, 0% humidity) calibrated airspeed is the same as equivalent airspeed (EAS) and true airspeed (TAS).

How to get TAS from CAS?

CAS + pressure + temperautre => TAS

What is EAS?

Equivalent Airspeed (EAS) is the calibrated airspeed (CAS) corrected for compressibility effects, representing the speed at sea level in the International Standard Atmosphere (ISA) that would produce the same dynamic pressure as the aircraft's true airspeed (TAS) at altitude.