Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. For certain airplanes, this proposed AD would require replacing the outboard stabilizing fitting and certain adjacent components of the main landing gear (MLG) support beam. This proposed AD would also require repetitive inspections for discrepancies of the outboard stabilizing fitting, walking beam hanger, and rear spar attachment, and corrective actions if necessary. For certain airplanes, this proposed AD would provide an alternative one-time inspection of the outboard stabilizing fitting for discrepancies and corrective actions if necessary, which would extend the compliance time for the replacement of the outboard stabilizing fitting. For certain other airplanes, this proposed AD would also require performing a torque check of the aft pin of the outboard stabilizing fitting, and corrective actions if necessary. This proposed AD results from reports of findings of fatigue cracking of the outboard stabilizing fitting and stress corrosion cracking of the bolts attaching the fitting to the wing rear spar. We are proposing this AD to detect and correct that cracking, which could result in disconnection of the MLG actuator from the rear spar and support beam, and consequent damage to the hydraulic system causing hydraulic fluid leakage and loss of control of the airplane.