Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737 -300, -400, and -500 series airplanes. This proposed AD was prompted by reports of nuisance stick shaker activation while accelerating to cruise speed at the top of a climb due to frozen angle of airflow (AOA) sensor vanes. This proposed AD would require installing new external case heaters (ECHs) on the left and right AOA sensors, performing repetitive functional tests and applicable corrective actions, and accomplishing applicable concurrent actions. The FAA is proposing this AD to address the unsafe condition on these products.