In a multi-engine airplane, which engine is considered the critical engine?

• A. Upwind
• B. Downwind
• C. Left
• D. Right

Answer: (B)

The key idea is understanding what makes an engine “critical.” The critical engine is the one whose failure would cause the greatest loss of directional control for the airplane. In most two-engine airplanes, the downwind engine is considered the critical one because when it fails, the remaining engine’s thrust, combined with the engine’s location on the wing and the propeller’s rotation, creates the larger yaw and control difficulties. This means you’d have to work harder with rudder and bank to keep a straight heading than if the other engine failed. The other options describe location rather than which failure creates the bigger control challenge, so they don’t align with the typical behavior of a failed engine in a twin.