How does an aircraft stall warning system work?

Stall warning alerts pilots before aerodynamic stall. Components: Angle of Attack (AOA) vanes or probes measuring local flow angle, Air data for configuration and speed corrections, Stick shaker motors that vibrate the control column, Stick pusher (some aircraft) that applies nose-down force. Logic: Warning activates at specified margin before stall AOA (typically 5-7 degrees), adjusted for configuration (flaps, gear), weight, and ice accretion. Aural warnings accompany stick shaker. Multiple AOA sensors with monitoring for validity. Integration with flight control laws (FBW) may include AOA limiting. System must be reliable (failure rate <10^-5 per flight hour) and nuisance-free. Testing validates margins across flight envelope.