Airworthiness Directives; The Boeing Company Airplanes

FAA / Federal Register · 2021-27957

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-200 and -200C series airplanes. This AD was prompted by reports of nuisance stick shaker activation while the airplane was accelerating to cruise speed at the top of a climb. Investigation revealed that the activation was caused when the angle of attack (AOA) (also known as angle of airflow) sensor vanes froze and malfunctioned due to insufficient heat in certain AOA sensors to prevent ice buildup. This AD requires inspecting the AOA sensors for certain part numbers or vane shapes, and replacing any affected AOA sensor with a new or serviceable sensor. The FAA is issuing this AD to address the unsafe condition on these products.