What is Stall (flight)?
A '''stall''' is what happens when an aerofoil can not make enough [[Lift (force)|lift]] to keep the aircraft in flight. Stalling can be risky and dangerous when caused unintentionally or with lack of enough vertical distance for recovery. [[File:1915ca abger fluegel (cropped and mirrored).jpg|thumb|Airflow separating from an [[airfoil]] at a high angle of attack, as occurs at a stall.]] == Cause == A stall is caused when the critical angle of attack, or AoA, is exceeded. The angle of attack, which is the angle between the chord line and relative wind of the aircraft's wing, is typically around 15 degrees. == Signs of the stall == The signs of the developing stall are: *stall warning horn (if equipped) *less effective controls *light buffet (shaking) in the stick and [[rudder]] pedals. The signs of a full stall are: *heavy buffet in the controls *nose drops *the aircraft descends (falls). There is a chance of entering a spin if the aircraft controls are not coordinated. == Recovery from a stall == To recover from a stall, the pilot must push the nose down. Then the pilot must increase the engine power using the throttle. When air speed increases again, the pilot can level the wings and pull up to return the aircraft to normal flight. == Deep stall == An aircraft with a T tail is at risk from deep stall, because the turbulent air coming back off the stalled wings covers the elevators and makes it very difficult to push the nose down and recover. == Training == In the United States the FAA requires private pilots to understand the theory and execute stalls at [[altitude]]. This, ideally, enables them to recognize the indicators of a stall and prevent an accidental stall at low altitude. === Power on stall (Departure stall) === Used to simulate a stall while executing a [[Takeoff|take off]], go around or climbing. The steps to execute a power on stall are: # Pick a safe altitude to allow for a timely recovery. # Execute a [[clearing turn]]. # Slow the aircraft down (optional). # Add full power while i