Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 747 airplanes. The existing AD currently requires repetitive visual inspections around the bushings of the wing landing gear (WLG) beam outboard end fittings for corrosion, and rework if necessary; and ultrasonic inspections for cracks of the outboard end fittings of the WLG support beams, and rework if necessary. Since we issued that AD, there have been new reports of corrosion damage to the end fittings of the WLG support beams, and one report of subsequent cracking in the end fittings. This proposed AD would add airplanes and repetitive inspections of the outboard end fitting of the left and right WLG support beams for cracks and corrosion, and corrective actions if necessary. We are proposing this AD to detect and correct corrosion and subsequent cracking in the outboard end fittings, which could result in separation of the fitting and damage to adjacent flight control cables and hydraulic systems and consequent reduced controllability of the airplane.