Airspeed indicator

An airspeed indicator is the cockpit instrument that shows indicated airspeed from the difference between pitot pressure and static pressure. It is used in all phases of flight to keep the aircraft within safe speed limits for climb, cruise, approach and flap operation. Its colored arcs and lines mark important operating ranges such as normal operating speed, flap range and the caution area. The pilot cross-checks it with attitude, power and other instruments and treats abnormal readings as a possible pitot-static system problem.