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Primary measurement system of the United States

Aviation Mechanic General (AMG) practice question 10 of 25 on Mathematics. ACS element AM.I.H.K11 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONWhich system of measurement does the United States primarily use?

  1. AThe conventional (English) system
  2. BThe International System of Units (SI)
  3. CThe metric system, since the 1970s
Show the answer and explanation

Correct answer: A. The conventional (English) system

  • A — correct The handbook states that the United States primarily uses the conventional (U.S. or English) system, although it is slowly integrating the metric system.
  • B — incorrect SI is the metric system; the United States is integrating it slowly but does not primarily use it.
  • C — incorrect A recommendation to transition to metric within ten years was initiated in the 1970s, but the movement lost momentum and the U.S. continues to use both systems.

BACKGROUND

The conventional (U.S. or English) system of measurement is part of the cultural heritage from the days when the thirteen colonies were under British rule, and it includes units such as inches, feet, yards, miles, ounces, pints, gallons and pounds. Because it was not set up systematically, it contains a random collection of conversions, such as 1 mile = 5,280 feet and 1 foot = 12 inches. The metric system, also called the International System of Units (SI), is the dominant language of measurement used today. The United States primarily uses the conventional system while slowly integrating the metric system; a 1970s recommendation to transition within ten years lost momentum, so both systems remain in use.

STUDY TIP

Expect questions that contrast the conventional system's irregular conversions with the metric system's decimal prefixes.

KEY POINTS

  • U.S. primarily uses the conventional (English) system.
  • Metric = SI, based on decimal prefixes.
  • Both systems remain in use, so conversions are needed.

SOURCES

  • FAA-H-8083-30B ch03 "Conventional (U.S. or English) System"
  • FAA-H-8083-30B ch03 "Measurement Systems & Conversions"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.