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AerodynamicsQuestion 446 of 934

A wing is at a height of one-tenth of its span above the ground. What is the reduction in induced drag?

  1. About 1.4 percent
  2. About 47.6 percent
  3. About 23.5 percent
  4. About 100 percent
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Correct answer: About 47.6 percent

At one-tenth of the span, the induced drag falls by 47.6 percent. The effect is large only when the wing is very close to the ground.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 5: Aerodynamics of Flight — Ground Effect, page 108

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Questions last reviewed: 18 October 2026