Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model MD-90-30 airplanes. This AD was prompted by reports of stick shaker activation at airspeeds that were above the stall protection system's stick shaker schedule. This AD requires installing angle-of-attack (AOA) sensor external case heaters on the existing AOA sensors, installing additional wires, and doing a functional test and applicable corrective actions. We are issuing this AD to address the unsafe condition on these products.