Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 777 airplanes. This proposed AD was prompted by heat damage and cracks at the pivot joint location of the main landing gear (MLG) inner cylinder/truck beam. This proposed AD would require repetitive lubrication of the MLG pivot joints; repetitive detailed inspections of the outer diameter chrome on the center axles of the MLG for chicken-wire cracks, corrosion, and chrome plate distress; repetitive magnetic particle inspections of the outer diameter chrome on the center axles of the MLG for cracks; and related investigative and corrective actions if necessary. We are proposing this AD to detect and correct cracking in the MLG center axle and shock strut inner cylinder lugs (pivot joint), which could result in fracture of the MLG pivot joint components and consequent collapse of the MLG.