A stall is what happens when an aerofoil can not make enough lift to keep the aircraft in level flight. Stalling is risky and can be dangerous during low-level flying.
Causes[change | change source]
The stall is most likely to happen because of low air speed. To make up for low speed, a pilot will raise the nose of the aircraft to increase angle of attack, increase Lift Coefficient and keep the same lift. However, after a critical angle of attack is passed (often around 16 degrees) the lift stops increasing and actually collapses, causing a stall.
The critical angle of attack will always stall the aircraft. It does not matter whether the aircraft is going fast or slow.
Signs of the stall[change | change source]
The signs of the developing stall are:
low air speed, high nose position, less effective controls, and 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 the chance of entering a spin if the wings are not level.
Recovery from a Stall[change | change source]
To recover from a stall, the pilot must push the nose down. Then he must increase the engine power using the throttle. When air speed increases again, the pilot can level his wings and pull up to return to his assigned flight level.
Deep Stall[change | change source]
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.
Stall Turn[change | change source]
A Stall Turn is an aerobatic maneuvre which uses the stall. The pilot dips his nose to get up some speed, then pulls up sharply, stalling his wings and destroying lift. The aircraft stops in the air with its nose pointing straight up, before toppling over sideways to the right or left.