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Flight Phase

Mach number

The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.

Quick answer: The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.

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Quick answer

The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.

Why it matters

Mach number matters because it supports clear communication in Flight Phase contexts for Pilots, Air Traffic Controllers, and Cabin Crew. It also connects to aviation training and exam language such as ICAO Level 4, ICAO Level 5, ICAO Level 6, and EASA FCL.055.

Editorial context

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Questions and answers

Questions and answers

What is Mach number?

In this glossary, Mach number refers to: The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.

How is Mach number used in aviation?

In aviation communication, this term appears in contexts such as: "Maintain Mach decimal eight zero or greater, advise if unable due to turbulence or performance limitations."

Why does Mach number matter in aviation?

Mach number matters because it supports clear communication in Flight Phase contexts for Pilots, Air Traffic Controllers, and Cabin Crew. It also connects to aviation training and exam language such as ICAO Level 4, ICAO Level 5, ICAO Level 6, and EASA FCL.055.

Who uses Mach number?

Mach number is mainly used by Pilots, Air Traffic Controllers, and Cabin Crew.

What category does Mach number belong to?

In this glossary, Mach number is grouped under Flight Phase. Related pages in this category explain adjacent procedures, commands and operational concepts.

Where does this definition come from?

This definition is sourced from ICAO Doc 9432, FAA PCG and published by Protermify Aviation as a static aviation reference page.

Definition

The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.

Operational example

Maintain Mach decimal eight zero or greater, advise if unable due to turbulence or performance limitations.

Definition language

English reference definition

Source

ICAO Doc 9432, FAA PCG

Category

Flight Phase

Exam relevance

  • ICAO Level 4
  • ICAO Level 5
  • ICAO Level 6
  • EASA FCL.055

Target audience

  • Pilots
  • Air Traffic Controllers
  • Cabin Crew

Related terms

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