Summary
This document revises an earlier supplemental notice of proposed rulemaking (NPRM), applicable to all Gulfstream Aerospace Corporation Model G-159 airplanes, that would have required repetitive non-destructive testing inspections to detect corrosion of the skin of certain structural assemblies, and corrective action if necessary. The first supplemental NPRM also would have required x-ray and ultrasonic inspections to detect corrosion and cracking of the splicing of certain structural assemblies, and repair if necessary. This new action revises the proposed rule by limiting the time certain repetitive inspections may be repeated before corrective action must be taken. The actions specified by this new proposed supplemental AD are intended to detect and correct corrosion and cracking of the lower wing plank splices and spot-welded skins of certain structural assemblies, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.