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Why is airspeed indicator sealed with sea level pressure ?


Sea level is a benchmark - we compare all other pressures to air pressure at sea level. Airspeed can be deduced from the pressure of the air, because faster air has lower pressure. 


To be completely accurate, it needs to have its "zero", or baseline, at sea level pressure.  So we seal the airspeed indicators with sea level pressure to have the most accuracy. 

Categories: Aerodynamics