Airworthiness Directives; Boeing Model 737 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737 series airplanes, that requires a one-time inspection of the main landing gear (MLG) axle flange to detect cracking, and follow-on corrective actions. For certain airplanes, this amendment also requires replacement of the original brake mounting gasket with a more durable aluminum-nickel-bronze gasket, and installation of new shear studs, if necessary. For certain airplanes, this amendment requires modification of the mounting flange holes of the brake torque tube. This amendment is prompted by reports of cracking in the axle flange and by reports of deterioration of the brake mounting gasket. The actions specified by this AD are intended to prevent fracture of the MLG axle and separation of the wheel from the MLG, and consequent reduced controllability of the airplane.