Slow flight is a portion of an airplane

Fixed-wing aircraft

A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

's performance envelope above the speed at which the plane will stall

Stall (flight)

In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded...

, but below the aircraft's endurance speed. This part of the performance chart is also known as "the back side of the power curve" because when flying in this area, more power is required in order to go slower and still maintain straight and level flight

Flight

Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....

. A large angle of attack

Angle of attack

Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...

 is required in order to maintain the altitude of the aircraft.

At such low speeds, aircraft flight control surfaces begin to lose their effectiveness. Aileron

Aileron

Ailerons are hinged flight control surfaces attached to the trailing edge of the wing of a fixed-wing aircraft. The ailerons are used to control the aircraft in roll, which results in a change in heading due to the tilting of the lift vector...

s, in particular, are susceptible. The rudder

Rudder

A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...

 remains the most efficient flight surface and the adverse effect of yaw which alters pitch is useful for altering the direction of the aircraft without the need for aileron inputs. If the ailerons are used excessively it is probable one wing will stall (REVISION: Both wings must stall in order for an aircraft to spin. It's just that one wing is more stalled than the other) (due to the increased angle of attack) and send the aircraft into a spin

Spin (flight)

In aviation, a spin is an aggravated stall resulting in autorotation about the spin axis wherein the aircraft follows a corkscrew downward path. Spins can be entered intentionally or unintentionally, from any flight attitude and from practically any airspeed—all that is required is sufficient yaw...

. In modern aircraft, flight envelope protection

Flight envelope protection

right|thumb| 327 px| [[China Airlines Flight 006]] damaged by going outside its [[flight envelope]] to gain control after a drop in twenty seconds of 3,000 m...

 in the aircraft flight control system

Aircraft flight control systems

A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight...

prevents a pilot from controlling their aircraft into doing this.