Airworthiness Directives; McDonnell Douglas Model MD-90-30 Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes, that currently requires repetitive fluorescent penetrant and magnetic particle inspections to detect fatigue cracking of the main landing gear (MLG) piston, and repair if necessary. This amendment expands the applicability of the existing AD to require the currently required inspections, and corrective actions if necessary, on additional airplanes and MLG piston part numbers, and requires repetitive inspections for evidence of cracking in the paint topcoat of the MLG pistons. This amendment also requires replacement of certain MLG shock strut piston assemblies with new or serviceable improved assemblies, which terminates the requirements of this AD. The actions specified by this AD are intended to prevent fatigue cracking of MLG pistons, which could result in failure of the pistons, and consequent damage to the airplane structure and injury to flightcrew, passengers, or ground personnel. This action is intended to address the identified unsafe condition.