One-Engine-Inoperative Performance
One-Engine-Inoperative Performance is a core knowledge area on the Multi-Engine FAA written exam. This hub collects our 7 in-depth, ACS-aligned one-engine-inoperative performance articles — each written in plain English and grounded in the official FAA handbooks. Work through them below, then drill the topic with practice questions.
Single-Engine Service Ceiling and Absolute Ceiling
Single-engine service ceiling and absolute ceiling define how high a twin can climb—and survive—after an engine fails, making them critical OEI performance benchmarks every multi-engine pilot must understand.
Feathered versus Windmilling Propeller: The Performance Difference
A feathered propeller produces far less drag than a windmilling one, and understanding that difference is essential for predicting OEI climb performance and aircraft control after engine failure on a multi-engine aircraft.
Accelerate-Stop and Accelerate-Go Distance for Light Twins
Accelerate-stop and accelerate-go distances tell a multi-engine pilot whether the runway ahead is long enough to either reject a takeoff or continue on one engine if a failure occurs at a critical moment—understanding both is essential for safe light-twin operations.
Density Altitude and Single-Engine Climb Capability
At high density altitudes, a multi-engine airplane's single-engine climb capability can vanish entirely—understanding why and how to plan for it is critical to safe twin operations.
Multi-Engine Takeoff Planning and the Takeoff Decision Speed
Multi-engine takeoff planning centers on understanding Vmc, Vmca, and the decision speeds that define whether a crew can safely continue or abort after an engine failure at or near rotation.
VYSE (Blue Line) and VXSE: Best Single-Engine Climb Speeds
VYSE (blue line) marks the airspeed for the best single-engine rate of climb in a twin, while VXSE gives the steepest angle. Together they define your performance envelope after an engine failure — knowing when and how to use each can mean the difference between climbing away safely and settling into terrain.
Engine-Out Climb Performance and the Windmilling Propeller Drag Penalty
When one engine fails on a light twin, a windmilling propeller creates enormous drag and climb performance collapses—understanding exactly why, and the speeds that govern survival, is essential for every multi-engine pilot.
More Multi-Engine subjects
Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.