What is defined as the minimum speed for controlled flight in an aircraft?

The minimum speed for controlled flight in an aircraft is referred to as stall speed. This is the critical speed below which the wings cannot generate sufficient lift to keep the aircraft flying, leading to a loss of control in the air known as a stall. Each aircraft has a specific stall speed that varies depending on factors such as weight, configuration (flaps extended or retracted), and load factor.

Understanding stall speed is crucial for pilots as it defines the threshold for safe flight. If an aircraft is flown below this speed, it risks entering a stall condition, where recovery becomes challenging and can lead to dangerous situations, particularly close to the ground during takeoff or landing phases.

In contrast, climb speed, takeoff speed, and landing speed relate to specific phases of flight but do not represent the minimum speed for controlled flight. Climb speed is the speed at which an aircraft gains altitude efficiently, takeoff speed is the speed needed to lift off from the runway, and landing speed is the speed during descent before touchdown. Each of these speeds is higher than stall speed, and they focus on specific operational needs rather than the fundamental requirement for the aircraft to remain in controlled flight.