Airworthiness Directives; Boeing Model 737 Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737 airplanes. This AD requires modifying the elevator input torque tube assembly. This AD results from a report of a restriction in the pilot's elevator input control system. A design review performed on the elevator input torque tube assembly in the course of the investigation discovered possible failure modes that could lead to a jam of the elevator control system. We are issuing this AD to prevent loss of elevator control and consequent reduced controllability of the airplane.