This Aerospace Standard covers one type of maximum-allowable-airspeed instrument which gives a continuous indication of both indicated airspeed and maximum allowable airspeed not exceeding 650 knots.This Aerospace Standard establishes the essential minimum safe performance standards for pitot-static type of maximum-allowable-airspeed instruments primarily for use with turbine powered subsonic transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in Section 3.3.