Multi-Engine Preparation · Source-checked
Asymmetric thrust and the critical engine
Learning goals
- Explain why one engine failing yaws and rolls the airplane
- Describe what makes an engine 'critical'
With one engine inoperative, thrust is offset from the centerline, so the airplane yaws toward the dead engine and, through the loss of propeller slipstream over that wing, tends to roll the same way.
On many conventional twins whose propellers turn the same direction, one engine's failure is more adverse than the other's. That engine is called the critical engine. The Airplane Flying Handbook explains the contributing factors. Some twins have counter-rotating propellers, which changes this picture — your aircraft's AFM/POH and instructor tell you which applies.
Assigned reading
Airplane Flying Handbook (FAA-H-8083-3C)
Chapter 13: Transition to Multiengine Airplanes — engine inoperative flight principles · Federal Aviation Administration · reviewed 2026-10-21
Self-check
Original practice questions for self-assessment only — not FAA test questions and not a certification.
Study preparation only. Not FAA-approved ground training, no endorsement, logbook or flight-time credit, and no guaranteed test result. Always follow your instructor and the approved AFM/POH for your aircraft.