The maximum speed of a plane that can be flown safely without stalling is known as the "stall speed." The stall speed of an aircraft depends on various factors, including its design, weight, wing configuration, and other aerodynamic characteristics.
Stall speed refers to the minimum speed at which an aircraft can maintain level flight without stalling, which is the loss of lift due to exceeding the critical angle of attack. The critical angle of attack is the angle at which the airflow over the wings becomes disrupted, resulting in a loss of lift.
The stall speed varies for different aircraft and can be influenced by factors such as the wing's shape, size, and camber, as well as the aircraft's weight, center of gravity, and configuration (such as the presence of flaps or slats).
For commercial airliners, the stall speed is typically around 130-160 knots (150-185 mph or 240-300 km/h). However, it's important to note that stall speeds can differ significantly between aircraft types and even within different configurations of the same aircraft.
To ensure safe flight, pilots are trained to operate the aircraft within specific speed limitations, including staying above the stall speed. Operating below the stall speed can lead to loss of control and potentially result in a stall or spin, which can be dangerous.
It's crucial for pilots to adhere to the specific guidelines and limitations provided by the aircraft manufacturer and aviation regulatory authorities to maintain safe and controlled flight.