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Aircraft systems and instrumentsQuestion 622 of 934

During the pretakeoff check, the rpm drop exceeds the allowed limit on one magneto. What should the pilot do?

  1. Not fly until the problem is corrected
  2. Fly with the switch set to the good magneto
  3. Fly if the rpm returns to normal at cruise
  4. Lean the mixture, then take off and watch the rpm
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Correct answer: Not fly until the problem is corrected

The cause could be fouled plugs, broken or shorted wires, or improperly timed firing.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 7: Aircraft Systems — Ignition System, page 175

Practice aircraft systems and instruments

Questions last reviewed: 18 October 2026