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Effect of wing washout on stall

Aviation Mechanic General (AMG) practice question 6 of 20 on Physics for Aviation. ACS element AM.I.J.K7 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONAn airplane wing is built with a greater angle of incidence at the root than at the tip. During the initial stages of a stall, what is the effect of this washout?

  1. AThe wingtip stalls before the root, so aileron control is lost early
  2. BThe wing root stalls before the tip, so aileron control is retained
  3. CThe entire wing stalls at the same moment, which reduces drag
Show the answer and explanation

Correct answer: B. The wing root stalls before the tip, so aileron control is retained

  • A — incorrect This is the opposite of the intended effect. The higher root incidence makes the root, not the tip, reach the stalling angle first.
  • B — correct Washout causes the inboard part of the wing to stall before the outboard part, which helps maintain aileron control during the initial stages of a wing stall.
  • C — incorrect Washout is designed specifically to make the stall progress from root to tip rather than occur all at once, and it is not a drag-reduction feature.

BACKGROUND

The angle of incidence is the angle formed by the wing chord line and the horizontal plane passing through the longitudinal axis of the aircraft. Many airplanes are designed with a greater angle of incidence at the root of the wing than at the tip, a feature called washout. Because the root reaches its stalling angle of attack first, the inboard part of the wing stalls before the outboard part. The ailerons, located outboard, remain in effective airflow, which helps the pilot maintain roll control during the initial stages of a stall. Leading edge slots placed ahead of the ailerons serve a similar purpose.

STUDY TIP

Associate washout with the phrase 'root stalls first, ailerons keep working'; it is a stall-behavior feature, not a lift or drag device.

KEY POINTS

  • Washout = greater angle of incidence at root than at tip
  • Inboard wing stalls before outboard wing
  • Purpose is to maintain aileron control during a stall

SOURCES

  • FAA-H-8083-30B ch05 "Airfoils" (angle of incidence and washout)
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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.