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Definition of center of gravity

Aviation Mechanic General (AMG) practice question 14 of 25 on Weight and Balance. ACS element AM.I.C.K5 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONThe center of gravity of an aircraft is the point at which

  1. Athe center of lift is located, so no flight control force is needed
  2. Bthe nose-heavy and tail-heavy moments are exactly equal
  3. Call horizontal measurements for balance are taken
Show the answer and explanation

Correct answer: B. the nose-heavy and tail-heavy moments are exactly equal

  • A — incorrect The CG is close to the center of lift on an efficiently loaded aircraft, but the two points are not the same and the CG is defined by balance, not lift.
  • B — correct The handbook defines the CG as the point where all the weight is concentrated and balanced, with the nose-heavy and tail-heavy moments exactly equal.
  • C — incorrect That describes the datum, the reference plane for arms, not the CG.

BACKGROUND

The center of gravity (CG) is the point at which all the weight of the aircraft is concentrated and balanced, so the aircraft could be supported at that point. At the CG the magnitude of the nose-heavy and tail-heavy moments are exactly equal, and an aircraft suspended from it would have no tendency to rotate nose up or nose down. The handbook compares the CG to the fulcrum of a first-class lever or a seesaw. Knowing the CG is essential because an aircraft that does not balance properly can exhibit poor maneuverability and controllability.

STUDY TIP

Define the CG in terms of equal moments on either side; that same idea is used to prove a CG calculation is correct.

KEY POINTS

  • The CG is the balance point of the aircraft.
  • Nose-heavy and tail-heavy moments are equal at the CG.
  • It behaves like the fulcrum of a lever.

SOURCES

  • FAA-H-8083-30B ch06 "Center of Gravity (CG)"
Practice the Aviation Mechanic General (AMG) test →Timed 60-question exam, by ACS area, or review your misses. Free.
MORE ON WEIGHT AND BALANCE

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.