Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This action requires repetitive inspections to find cracks, fractures, or corrosion of each carriage spindle of the left and right outboard mid-flaps; and corrective action, if necessary. This action also provides for an optional action of overhaul or replacement of the carriage spindles, which would extend the repetitive inspection interval. This action is necessary to prevent severe flap asymmetry due to fractures of the carriage spindles on an outboard mid- flap, which could result in reduced control or loss of controllability of the airplane. This action is intended to address the identified unsafe condition.