Equivalent airspeed

Description

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 in function of the true airspeed (TAS) as shown.

Related formulas

Variables

EASequivalent airspeed (m/s)
TAStrue airspeed (m/s)
ρactual air density (kg/m3)
ρ0tandard sea level density (1.225 kg/m3 or 0.00237 slug/ft3) (kg/m3)