Mach Indicator

A Mach indicator is an instrument that displays the ratio of the aircraft’s true airspeed to the speed of sound (Mach number). It is standard equipment on aircraft that operate at high subsonic or transonic speeds, where Mach number becomes a critical performance and structural parameter.

Mach and V_MO/M_MO

High-performance aircraft have two maximum operating speed limits: V_MO (maximum operating indicated airspeed) and M_MO (maximum operating Mach number). At lower altitudes, V_MO is the active limit; at higher altitudes, M_MO becomes the limiting factor. Modern aircraft have overspeed warnings for both limits.

Related Terms

See also: Mach Number, V_NE.