What does the term "critical engine-out performance" refer to?

The term "critical engine-out performance" specifically refers to an aircraft's ability to maintain control and performance with one engine inoperative. This concept is crucial in aviation, particularly for multi-engine aircraft, as it addresses the challenges and risks associated with an engine failure during various phases of flight, such as takeoff or climb. Understanding this performance is vital for pilots to ensure safety and operational effectiveness during such scenarios.

The focus on maintaining control means that the aircraft must have sufficient thrust from the remaining engine(s) to enable safe handling, and that the aircraft can be flown without excessive yaw or bank that would occur due to the asymmetrical thrust. Performance metrics in this context include climb rates, minimum control speeds, and the ability to navigate the desired flight path effectively even after losing an engine.