Airworthiness Directives; British Aerospace Model HS 748 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace Model HS 748 series airplanes. This action requires revising the Airplane Flight Manual (AFM) to modify the limitation that prohibits the positioning of the power levers below the flight idle stop during flight, and to add a statement of the consequences of positioning the power levers below the flight idle stop during flight. This amendment is prompted by incidents and accidents involving airplanes equipped with turboprop engines in which the propeller ground beta range was used improperly during flight. The actions specified in this AD are intended to prevent loss of airplane controllability, or engine overspeed and consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.