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Aircraft systems and instrumentsQuestion 602 of 934

How does the use of carburetor heat affect the mixture?

  1. It enriches the mixture; the heated air is less dense
  2. It leans the mixture, because the heated air is denser
  3. It does not change the mixture, only the air temperature
  4. It leans the mixture, because more fuel flows
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Correct answer: It enriches the mixture; the heated air is less dense

Heated air is less dense, so the mixture becomes richer. Engine power can also decrease by up to 15 percent.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 7: Aircraft Systems — Induction Systems — Carburetor Heat, page 170

Practice aircraft systems and instruments

Questions last reviewed: 18 October 2026