What is critical engine-out speed?

Critical engine-out speed is defined as the speed necessary to maintain controlled flight when one engine becomes inoperative, particularly in multi-engine aircraft. This speed ensures that the aircraft can maintain altitude and control, which is essential for safe operation during an engine failure scenario.

When an engine fails, the aircraft will experience a yawing motion towards the inoperative engine due to the asymmetrical thrust. The critical engine-out speed is calculated to be above the minimum controllable airspeed, allowing the pilot to retain control over the aircraft and make necessary adjustments to the flight path.

Understanding this speed is crucial for pilots, as it directly affects their decision-making and safety during takeoff and climb-out phases, where engine losses are most critical. It is a vital part of flight training and operations for multi-engine aircraft reliability and pilot competency.