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Direction of balance tab movement

Aviation Mechanic Airframe (AMA) practice question 5 of 16 on Flight Controls. ACS element AM.II.C.K12 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONA balance tab moves in what way in relation to the primary flight control surface on which it is installed?

  1. AIt stays fixed in neutral
  2. BIn the same direction, but farther
  3. CIn the opposite direction
Show the answer and explanation

Correct answer: C. In the opposite direction

  • A — incorrect A tab that remains fixed would provide no aerodynamic assistance to the primary control surface.
  • B — incorrect Moving the same way as the surface would not produce the assisting force that a balance tab is designed to create.
  • C — correct Balance tabs are designed to move in the opposite direction of the primary flight control so aerodynamic forces on the tab assist in moving the surface.

BACKGROUND

Trim controls include trim tabs, servo tabs, balance tabs, and spring tabs, and each is hinged to its parent primary control surface but operated by an independent control. Trim tabs are small airfoils recessed into the trailing edges of the primary control surfaces, and they let the pilot trim out an unbalanced condition without exerting pressure on the primary controls. Servo tabs, sometimes called flight tabs, are used primarily on large main control surfaces; only the servo tab moves in response to pilot movement of the primary flight controls, and it aids in moving and holding the main surface. Balance tabs are designed to move in the opposite direction of the primary flight control, so that aerodynamic forces acting on the tab assist in moving the primary control surface. Spring tabs look similar to trim tabs but serve the same purpose as hydraulic actuators, aiding the pilot in moving the primary control surface.

STUDY TIP

Sort the four tabs by what each one does before the exam: trim relieves pressure, servo moves the surface, balance opposes the surface, spring boosts pilot effort.

KEY POINTS

  • A balance tab moves opposite to the primary control surface.
  • Its aerodynamic force assists movement of that surface.
  • Trim, servo, and spring tabs each have a different job.

SOURCES

  • sources/ama-airframe/ch02.txt "Trim Controls"
Practice the Aviation Mechanic Airframe (AMA) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON FLIGHT CONTROLS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.