Equivalent airspeed (in function of impact pressure and static pressure)


Equivalent airspeed (EAS) is the airspeed at sea level in the International Standard Atmosphere at which the dynamic pressure is the same as the dynamic pressure at the true airspeed (TAS) and altitude at which the aircraft is flying. In low-speed flight, it is the speed which would be shown by an airspeed indicator with zero error. It is useful for predicting aircraft handling, aerodynamic loads, stalling etc.

It can be calculated as a function of impact pressure and static pressure (valid for subsonic flow)

Related formulas


EASequivalent airspeed (m/s)
a0standard speed of sound at 15 °C (661.47 knots) (m/s)
Pstatic pressure (Pa)
P0standard sea level pressure (1013.25 hPa) (Pa)
qcimpact pressure (Pa)