Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 airplanes. That AD currently requires repetitive inspections to detect cracking of the main landing gear (MLG) shock strut pistons, and replacement of a cracked piston with a new or serviceable part. This action would remove certain airplanes but would require that the existing inspections, and corrective actions if necessary, be accomplished on additional MLG shock strut pistons. This action also would require replacing the MLG shock strut pistons with new improved parts, which would terminate the repetitive inspections. This action is necessary to prevent fatigue cracking of the MLG pistons, which could result in failure of the pistons and consequent damage to the airplane structure or injury to airplane occupants. This action is intended to address the identified unsafe condition.