Mach meter


The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying.

Source: Pilot's Handbook of Aeronautical Knowledge (definition from the FAA-H-8083-25B, 2016; current: FAA-H-8083-25C, 2023, with the October 2025 addendum).

Related terms

Glossary last updated 2026-10-28.