A “stall warning” can be produced synthetically by electronic means, by a system that may malfunction. What are the natural stall warnings confirming an approaching stall?
(1) Aerodynamic buffeting
(2) Increased aileron effectiveness
(3) Inability to arrest a rate of descent
(4) Stick pusher activation
Refer to figure.
STALL
A stall is an aerodynamic condition which occurs when smooth airflow over the airplane’s wings is disrupted, resulting in loss of lift. Specifically, a stall occurs when the AOA—the angle between the chord line of the wing and the relative wind—exceeds the wing’s critical AOA. It is possible to exceed the critical AOA at any airspeed, at any attitude, and at any power setting.
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Impending Stall—an impending stall occurs when the AOA causes a stall warning, but has not yet reached the critical AOA. Indications of an impending stall can include buffeting, stick shaker, or aural warning.
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Full Stall—a full stall occurs when the critical AOA is exceeded. Indications of a full stall are typically that an uncommanded nose-down pitch cannot be readily arrested, and this may be accompanied by an uncommanded rolling motion. The flying controls will feel unresponsive or “mushy”. For airplanes equipped with stick pushers, its activation is also a full stall indication.
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