Airworthiness Directives; Boeing Model 737-600, -700, and 800 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, -700, and 800 series airplanes. This action requires a one-time inspection to detect loose nuts installed on the bolts at each end of the input rods connected to each elevator power control unit (PCU), and corrective action, if necessary. This amendment is prompted by reports of loose nuts on the bolts that connect the lower input crank arm and the vernier adjustment input rod of the elevator PCU. The actions specified in this AD are intended to detect and correct loose nuts on the bolts of the input crank arms of the elevator PCU, which could result in the loss of pivot bolts on the PCU and consequent loss of control of the airplane during takeoff and landing.