Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 727 airplanes. This proposed AD would require repetitive inspections for cracking or corrosion of the threaded end of the lower segment of the main landing gear (MLG) side strut, and corrective actions if necessary. This proposed AD also would require prior or concurrent inspection for cracking or corrosion of the threads and thread relief area of the lower segment, corrective action if necessary, and re-assembly using corrosion inhibiting compound. This proposed AD results from reports of the threads cracking on the MLG side strut lower segment. We are proposing this AD to prevent a fractured side strut, which could result in collapse of the MLG.