True airspeed

The true flight speed (Engl. true air speed, TAS), also adjusted equity speed, the actual speed of an aircraft relative to the surrounding medium. To calculate the true air speed is in the modern aviation in addition to flight speed equivalent density in the altitude. The true airspeed decreases in air density absinkender to the Berichtigten flight speed. For pilots of small aircraft first approximation appears in the following rule of thumb sufficiently precise

For example, at an altitude of 5000 ft at an IAS of 100 kt with 5 * 2%, ergo 10% higher speed, TAS to 110 kt. In high altitude, the 'TAS' preferably in Mach, relative to the speed of sound,. If exceeded Mach 1, is the supersonic aircraft in flight.