Roll Control (Ailerons)

081-05-04Pablo Asensio Martínez2026-04-011 min

Mechanism

Ailerons work by changing the camber of the outer wing section.

  • Stick Left: Left aileron UP (decreases lift) -> Left wing drops. Right aileron DOWN (increases lift) -> Right wing rises.

Adverse Yaw

When banking (e.g., to the left):

  • The Right Wing (Up-going) produces More Lift -> Therefore produces More Induced Drag.
  • The Left Wing (Down-going) produces Less Lift -> Less Induced Drag.
  • Difference in drag yaws the nose to the Right (Opposite to the turn).

Solutions

  1. Differential Ailerons: The up-going aileron travels further up than the down-going travels down. Reduces drag on the up-going wing (less projection) and increases drag on the down-going wing (more projection).
  2. Frise Ailerons: The leading edge of the Up-going aileron protrudes below the wing surface, creating parasite drag to counteract the induced drag of the other wing.
  3. Roll Spoilers: Spoilers on the down-going wing extend to kill lift AND add drag (yawing IN to the turn).
Written and reviewed by

Pablo Asensio · 2026-04-01

Aeronautical engineer. Passed the thirteen EASA ATPL(A) theoretical knowledge exams studying from these very notes. Writes and reviews each topic against the Part-FCL Learning Objectives.

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