by xiaok » 05 May 2021, 02:59
We recently encountered an in flight stick shaker event with A/P engage. Shortly after stick shaker activate, A/P disengage automatically. After decoded the QAR data , we found the vane angle-of-attack rapidly increases from approximately 2.8 degrees to approximately 17.9 degrees, where stick shaker activates momentarily. So we consider this was a nuisance stick shaker event which may be led by turbulence. I know the AOA trip point values change from 13.0 to 23.5 degrees depending on flap position, and SMYDs also use the other data for bias calculations. However, the AOA normal trip point schedule at each flap lever position did not state in AMM. Does anyone know the SMYD AOA trip threshold value at each flap lever position ?